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| M TC646B/TC648B/TC649B PWM Fan Speed Controllers With Auto-Shutdown, Fan Restart and FanSenseTM Technology for Fault Detection Features * Temperature-Proportional Fan Speed for Acoustic Noise Reduction and Longer Fan Life * Efficient PWM Fan Drive * 3.0V to 5.5V Supply Range: - Fan Voltage Independent of TC646B/ TC648B/TC649B Supply Voltage - Supports any Fan Voltage * FanSenseTM Fault Detection Circuit Protects Against Fan Failure and Aids System Testing (TC646B/TC649B) * Automatic Shutdown Mode for "Green" Systems * Supports Low Cost NTC/PTC Thermistors * Over-Temperature Indication (TC646B/TC648B) * Fan Auto-Restart * Space-Saving 8-Pin MSOP Package Description The TC646B/TC648B/TC649B devices are new versions of the existing TC646/TC648/TC649 fan speed controllers. These devices are switch-mode fan speed controllers that incorporate a new fan auto-restart function. Temperature-proportional speed control is accomplished using pulse width modulation. A thermistor (or other voltage output temperature sensor) connected to the VIN input supplies the required control voltage of 1.20V to 2.60V (typical) for 0% to 100% PWM duty cycle. The auto-shutdown threshold/temperature is set by a simple resistor divider on the VAS input. An integrated Start-Up Timer ensures reliable fan motor startup at turn-on, coming out of shutdown mode, autoshutdown mode or following a transient fault. A logic low applied to VIN (pin 1) causes fan shutdown. The TC646B and TC649B also feature Microchip Technology's proprietary FanSense technology for increasing system reliability. In normal fan operation, a pulse train is present at SENSE (pin 5). A missingpulse detector monitors this pin during fan operation. A stalled, open or unconnected fan causes the TC646B/ TC649B device to turn the VOUT output on full (100% duty cycle). If the fan fault persists (a fan current pulse is not detected within a 32/f period), the FAULT output goes low. Even with the FAULT output low, the VOUT output is on full during the fan fault condition in order to attempt to restart the fan. FAULT (TC646B) or OTF (TC648B) is also asserted if the PWM reaches 100% duty cycle, indicating that maximum cooling capability has been reached and a possible overheating condition exists. The TC646B, TC648B and TC649B devices are available in 8-pin plastic MSOP, SOIC and PDIP packages. The specified temperature range of these devices is -40 to +85C. Applications * * * * * * Personal Computers & Servers LCD Projectors Datacom & Telecom Equipment Fan Trays File Servers General-Purpose Fan Speed Control Package Types MSOP, PDIP, SOIC VIN 1 CF 2 VAS 3 GND 4 TC646B TC649B 8 7 6 5 VDD VOUT FAULT SENSE VIN 1 CF 2 VAS 3 GND 4 TC648B 8 7 6 5 VDD VOUT OTF NC 2003 Microchip Technology Inc. DS21755B-page 1 TC646B/TC648B/TC649B Functional Block Diagram TC646B/TC649B VOTF VIN Note VDD Control Logic CF Clock Generator 3xT PWM Timer Start-up Timer VSHDN Missing Pulse Detect 10 k 70 mV (typ) Note: The V OTF comparator is for the TC646B device only. VOUT VAS FAULT SENSE GND TC648B VIN VOTF VDD Control Logic CF Clock Generator Start-up Timer VSHDN OTF VOUT VAS NC GND DS21755B-page 2 2003 Microchip Technology Inc. TC646B/TC648B/TC649B 1.0 ELECTRICAL CHARACTERISTICS PIN FUNCTION TABLE Name VIN CF VAS GND SENSE/NC FAULT/OTF VOUT VDD Function Analog Input Analog Output Analog Input Ground Analog Input. No Connect (NC) for TC648B Digital (Open-Drain) Output OTF for TC648B Digital Output Power Supply Input Absolute Maximum Ratings Supply Voltage (VDD ) .......................................................6.0V Input Voltage, Any Pin................(GND - 0.3V) to (VDD +0.3V) Operating Temperature Range ....................- 40C to +125C Maximum Junction Temperature, TJ ........................... +150C ESD Protection on all pins ........................................... > 3 kV Notice: Stresses above those listed under "Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS Electrical Specifications: Unless otherwise specified, all limits are specified for -40C < TA < +85C, VDD = 3.0V to 5.5V. Parameters Supply Voltage Supply Current, Operating Supply Current, Shutdown Mode VOUT Output Sink Current at VOUT Output Source Current at VOUT Output VIN , VAS Inputs Input Voltage at VIN for 100% PWM Duty Cycle Over-Temperature Indication Threshold Over-Temperature Indication Threshold Hysteresis VC(MAX) - VC(MIN) Hysteresis on Auto-Shutdown Comparator Auto-Shutdown Threshold Voltage Applied to VIN to Ensure Shutdown Mode Voltage Applied to VIN to Release Shutdown Mode Hysteresis on VSHDN , VREL VIN , VAS Input Leakage Note 1: 2: VC(MAX) VOTF VOTF-HYS VC(SPAN) VHAS VAS VSHDN VREL VHYST IIN 1.3 -- VC(MAX) VC(SPAN) -- VDD x 0.19 -- - 1.0 2.45 2.60 VC(MAX) + 20 mV 80 1.4 70 -- -- -- 0.03 X VDD -- 1.5 -- VC(MAX) VDD x 0.13 -- -- +1.0 2.75 V V mV V mV V V V V A Note 1 VDD = 5V For TC646B and TC648B For TC646B and TC648B IOL IOH 1.0 5.0 -- -- -- -- mA mA VOL = 10% of VDD VOH = 80% of VDD Sym VDD IDD IDD(SHDN) Min 3.0 -- -- Typ -- 200 30 Max 5.5 400 -- Units V A A Pins 6, 7 Open, CF = 1 F, VIN = VC(MAX) Pins 6, 7 Open, CF = 1 F, VIN = 0.35V Conditions Ensured by design, tested during characterization. For VDD < 3.7V, tSTARTUP and tMP timers are typically 13/f. 2003 Microchip Technology Inc. DS21755B-page 3 TC646B/TC648B/TC649B ELECTRICAL CHARACTERISTICS (CONTINUED) Electrical Specifications: Unless otherwise specified, all limits are specified for -40C < TA < +85C, VDD = 3.0V to 5.5V. Parameters Pulse-Width Modulator PWM Frequency SENSE Input (TC646B & TC649B) SENSE Input Threshold Voltage with Respect to GND Blanking time to ignore pulse due to VOUT turn-on FAULT / OTF Output Output Low Voltage Missing Pulse Detector Timer Start-up Timer Diagnostic Timer Note 1: 2: V OL tMP tSTARTUP tDIAG -- -- -- -- -- 32/f 32/f 3/f 0.3 -- -- -- V sec sec sec IOL = 2.5 mA TC646B and TC649B, Note 2 Note 2 TC646B and TC649B VTH(SENSE) tBLANK 50 -- 70 3.0 90 -- mV sec fPWM 26 30 34 Hz CF = 1.0 F Sym Min Typ Max Units Conditions Ensured by design, tested during characterization. For VDD < 3.7V, tSTARTUP and tMP timers are typically 13/f. TEMPERATURE SPECIFICATIONS Electrical Characteristics: Unless otherwise noted, all parameters apply at V DD = 3.0V to 5.5V Parameters Temperature Ranges Specified Temperature Range Operating Temperature Range Storage Temperature Range Thermal Package Resistances Thermal Package Resistance, 8-Pin MSOP Thermal Package Resistance, 8-Pin SOIC Thermal Package Resistance, 8-Pin PDIP JA JA JA -- -- -- 200 155 125 -- -- -- C/W C/W C/W TA TA TA -40 -40 -65 -- -- -- +85 +125 +150 C C C Sym Min Typ Max Units Conditions DS21755B-page 4 2003 Microchip Technology Inc. TC646B/TC648B/TC649B TIMING SPECIFICATIONS tSTARTUP VOUT FAULT / OTF SENSE (TC646B and TC649B) FIGURE 1-1: TC646B/TC648B/TC649B Start-up Timing. 33.3 msec (CF = 1 F) tMP tDIAG tMP VOUT FAULT SENSE FIGURE 1-2: Fan Fault Occurrence (TC646B and TC649B). tMP VOUT FAULT Minimum 16 pulses SENSE FIGURE 1-3: Recovery From Fan Fault (TC646B and TC649B). 2003 Microchip Technology Inc. DS21755B-page 5 TC646B/TC648B/TC649B C2 1 F 8 R1 + 1 C3 0.1 F VIN VDD VOUT 7 K3 R6 C8 0.1 F C1 0.1 F + - VDD VIN R2 + - 3 C4 0.1 F TC646B TC648B TC649B VAS FAULT / OTF 6 K4 + - Current limited voltage source R5 VDD VAS + 2 CF GND K1 C7 .01 F K2 C6 1 F C5 0.1 F 4 SENSE 5 R3 R4 Current limited voltage source VSENSE (pulse voltage source) TC646B and TC649B Note: C5 and C7 are adjusted to get the necessary 1 F value. FIGURE 1-4: TC646B/TC648B/TC649B Electrical Characteristics Test Circuit. DS21755B-page 6 2003 Microchip Technology Inc. TC646B/TC648B/TC649B 2.0 Note: TYPICAL PERFORMANCE CURVES The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range. Note: Unless otherwise indicated, VDD = 5V, TA = 25C. 165 160 155 Pins 6 & 7 Open CF = 1 F 30.50 VDD = 5.5V Oscillator Frequency (Hz) CF = 1.0 F VDD = 3.0V 30.00 VDD = 5.5V 29.50 IDD (A) 150 145 140 135 130 125 -40 -25 -10 5 20 35 50 65 80 95 110 125 VDD = 3.0V 29.00 28.50 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (C) Temperature (C) FIGURE 2-1: IDD vs. Temperature. FIGURE 2-4: Temperature. 170 PWM Frequency vs. 16 14 12 VDD = 5.0V 165 160 155 Pins 6 & 7 Open CF = 1 F TA = +90C TA = +125C IOL (mA) IDD (A) 10 8 6 4 2 0 0 VDD = 5.5V VDD = 3.0V VDD = 4.0V 150 145 140 135 130 125 TA = -5C TA = -40C 50 100 150 200 250 300 350 400 450 500 550 600 3 3.5 4 4.5 5 5.5 VOL (mV) VDD (V) FIGURE 2-2: VOL. 16 14 12 PWM Sink Current (IOL) vs. FIGURE 2-5: IDD vs. VDD. 30 VDD = 5.0V VDD = 4.0V V DD = 5.5V VDD = 3.0V 27 24 VDD = 3.0V 21 18 15 0 100 200 300 400 500 600 700 800 -40 -25 -10 5 20 35 50 65 80 95 110 125 V DD = 5.5V IOH (mA) 10 8 6 4 2 0 IDD Shutdown (A) Pins 6 & 7 Open VIN = 0V VDD - VOH (mV) Temperature (C) FIGURE 2-3: vs. VDD - VOH. PWM Source Current (IOH) FIGURE 2-6: Temperature. IDD Shutdown vs. 2003 Microchip Technology Inc. DS21755B-page 7 TC646B/TC648B/TC649B Note: Unless otherwise indicated, VDD = 5V, TA = 25C. 70 60 50 VDD = 4.0V 40 30 20 10 -40 -25 -10 5 20 35 50 65 80 95 110 125 VDD = 5.5V VDD = 5.0V 74.0 73.5 VDD = 3.0V 73.0 VDD = 3.0V VDD = 4.0V IOL = 2.5 mA FAULT / OTF VOL (mV) VTH(SENSE) (mV) 72.5 72.0 71.5 71.0 70.5 70.0 69.5 -40 -25 -10 5 20 35 50 65 80 VDD = 5.5V VDD = 5.0V 95 110 125 Temperature (C) Temperature (C) FIGURE 2-7: Temperature. 2.610 FAULT / OTF VOL vs. FIGURE 2-10: Sense Threshold (VTH(SENSE)) vs. Temperature. 22 2.600 VDD = 5.5V VDD = 5.0V FAULT / OTF IOL (mA) 20 18 16 14 12 10 8 6 4 2 0 0 50 100 150 200 250 300 350 400 VDD = 5.5V VDD = 3.0V VDD = 5.0V VDD = 4.0V VC(MAX) (V) 2.590 VDD = 3.0V 2.580 CF = 1 F 2.570 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (C) VOL (mV) FIGURE 2-8: 1.220 VC(MAX) vs. Temperature. CF = 1 F FIGURE 2-11: 45.00 40.00 FAULT / OTF IOL vs. VOL. VOH = 0.8VDD VDD = 5.5V VDD = 5.0V VOUT IOH (mA) 1.210 35.00 30.00 25.00 20.00 15.00 10.00 VDD = 3.0V VC(MIN) (V) 1.200 VDD = 5.0V 1.190 VDD = 3.0V VDD = 4.0V 1.180 -40 -25 -10 5 20 35 50 65 80 95 110 125 5.00 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (C) Temperature (C) FIGURE 2-9: VC(MIN) vs. Temperature. FIGURE 2-12: vs. Temperature. PWM Source Current (IOH) DS21755B-page 8 2003 Microchip Technology Inc. TC646B/TC648B/TC649B Note: Unless otherwise indicated, VDD = 5V, TA = 25C. 30 25 VDD = 5.5V VDD = 5.0V VDD = 4.0V 15 10 VDD = 3.0V 5 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 VOL = 0.1VDD 2.630 2.625 2.620 VDD = 5.5V VDD = 5.0V VDD = 3.0V VOUT IOL (mA) 20 VOTF (V) 2.615 2.610 2.605 2.600 2.595 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (C) Temperature (C) FIGURE 2-13: Temperature. 0.80 0.75 0.70 0.65 VDD = 5.0V PWM Sink Current (IOL) vs. FIGURE 2-16: Temperature. 100 VOTF Threshold vs. VOTF Hysteresis (mV) VDD = 5.5V 95 90 VDD = 5.5V 85 80 75 70 VDD = 3.0V VSHDN (V) 0.60 0.55 0.50 0.45 0.40 0.35 0.30 -40 -25 -10 5 20 35 50 65 80 95 110 125 VDD = 3.0V VDD = 4.0V -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (C) Temperature (C) FIGURE 2-14: Temperature. 1.00 0.95 0.90 0.85 0.80 0.75 0.70 0.65 0.60 0.55 0.50 0.45 0.40 VSHDN Threshold vs. FIGURE 2-17: Over-Temperature Hysteresis (VOTF-HYS) vs. Temperature. VDD = 5.5V VDD = 5.0V VREL (V) V DD = 4.0V V DD = 3.0V -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (C) FIGURE 2-15: Temperature. VREL Threshold vs. 2003 Microchip Technology Inc. DS21755B-page 9 TC646B/TC648B/TC649B 3.0 PIN FUNCTIONS The descriptions of the pins are given in Table 3-1. TABLE 3-1: Pin 1 2 3 4 5 6 7 8 PIN FUNCTION TABLE Name VIN CF VAS GND Analog Input Analog Output Analog Input Ground Analog Input/No Connect. NC for TC648B. Digital (Open-Drain) Output OTF for TC648B Digital Output Power Supply Input Function SENSE/NC FAULT/OTF VOUT VDD 3.1 Analog Input (VIN) 3.5 The thermistor network (or other temperature sensor) connects to VIN. A voltage range of 1.20V to 2.60V (typical) on this pin drives an active duty cycle of 0% to 100% on the VOUT pin. The TC646B, TC648B and TC649B devices enter shutdown mode when 0 VIN VSHDN. During shutdown, the FAULT/OTF output is inactive and supply current falls to 30 A (typical). Digital (Open-Drain) Output (FAULT/OTF) 3.2 Analog Output (CF) FAULT/OTF goes low to indicate a fault condition. When FAULT goes low due to a fan fault (TC646B and TC649B devices), the output will remain low until the fan fault condition has been removed (16 pulses have been detected at the SENSE pin in a 32/f period). For the TC646B and TC648B devices, the FAULT/OTF output will also be asserted when the VIN voltage reaches the VOTF threshold of 2.62V (typical). This gives an over-temperature/100% fan speed indication. CF is the positive terminal for the PWM ramp generator timing capacitor. The recommended value for the CF capacitor is 1.0 F for 30 Hz PWM operation. 3.6 Digital Output (VOUT) 3.3 Analog Input (VAS) An external resistor divider connected to VAS sets the auto-shutdown threshold. Auto-shutdown occurs when VIN < VAS. The fan is automatically restarted when VIN > (VAS + VHAS). During auto-shutdown, the FAULT/OTF output is inactive and supply current falls to 30 A (typical). VOUT is an active-high complimentary output that drives the base of an external NPN transistor (via an appropriate base resistor) or the gate of an N-channel MOSFET. This output has asymmetrical drive. During a fan fault condition, the VOUT output is continuously on. 3.7 Power Supply Input (VDD) The VDD pin with respect to GND provides power to the device. This bias supply voltage may be independent of the fan power supply. 3.4 Analog Input (SENSE) 3.8 Ground (GND) Pulses are detected at SENSE as fan rotation chops the current through a sense resistor. The absence of pulses indicates a fan fault condition. Ground terminal. 3.9 No Connect (NC) No internal connection. DS21755B-page 10 2003 Microchip Technology Inc. TC646B/TC648B/TC649B 4.0 DEVICE OPERATION The TC646B/TC648B/TC649B devices are a family of temperature-proportional, PWM mode, fan speed controllers. Features of the family include minimum fan speed, fan auto-shutdown, fan auto-restart, remote shutdown, over-temperature indication and fan fault detection. The TC64XB family is slightly different from the original TC64X family, which includes the TC642, TC646, TC647, TC648 and TC649 devices. Changes have been made to adjust the operation of the device during a fan fault condition. The key change to the TC64XB family of devices (TC642B, TC647B, TC646B, TC648B, TC649B) is that the FAULT and VOUT outputs no longer "latch" to a state during a fan fault condition. The TC646B/ TC648B/TC649B family will continue to monitor the operation of the fan so that when the fan returns to normal operation, the fan speed controller will also return to normal operation (PWM mode). The operation and features of these devices are discussed in the following sections. The PWM approach to fan speed control results in much less power dissipation in the drive element. This allows smaller devices to be used and will not require special heatsinking to remove the power being dissipated in the package. The other advantage of the PWM approach is that the voltage being applied to the fan is always near 12V. This eliminates any concern about not supplying a high enough voltage to run the internal fan components, which is very relevant in linear fan speed control. 4.2 PWM Fan Speed Control The TC646B, TC648B and TC649B devices implement PWM fan speed control by varying the duty cycle of a fixed-frequency pulse train. The duty cycle of a waveform is the on time divided by the total period of the pulse. For example, if we take a 100 Hz waveform (10 ms) with an on time of 5.0 ms, the duty cycle of this waveform is 50% (5.0 ms / 10.0 ms). This example is shown in Figure 4-1. t 4.1 Fan Speed Control Methods The speed of a DC brushless fan is proportional to the voltage across it. This relationship will vary from fan-tofan and should be characterized on an individual basis. The speed versus applied voltage relationship can then be used to set up the fan speed control algorithm. There are two main methods for fan speed control. The first is pulse width modulation (PWM) and the second is linear. Using either method, the total system power requirement to run the fan is equal. The difference between the two methods is where the power is consumed. The following example compares the two methods for a 12V, 120 mA fan running at 50% speed. With 6V applied across the fan, the fan draws an average current of 68 mA. Using a linear control method, there is 6V across the fan and 6V across the drive element. With 6V and 68 mA, the drive element is dissipating 410 mW of power. Using the PWM approach, the fan voltage is modulated at a 50% duty cycle, with most of the 12V being dropped across the fan. With 50% duty cycle, the fan draws a RMS current of 110 mA and an average current of 72 mA. Using a MOSFET with a 1 RDS(on) (a fairly typical value for this low current), the power dissipation in the drive element would be: 12 mW (Irms2 * RDS(on)). Using a standard 2N2222A NPN transistor (assuming a Vce-sat of 0.8V), the power dissipation would be 58 mW (Iavg* Vce-sat). ton toff t = Period t = 1/f f = Frequency D = Duty Cycle D = ton / t FIGURE 4-1: Waveform. Duty Cycle of a PWM The TC646B/TC648B/TC649B devices generate a pulse train with a typical frequency of 30 Hz (CF = 1 F). The duty cycle can be varied from 0% to 100%. The pulse train generated by the TC646B/ TC648B/TC649B device drives the gate of an external N-channel MOSFET or the base of an NPN transistor. (shown in Figure 4-2). See Section 5.5, "Output Drive Device Selection", for more information on output drive device selection. 2003 Microchip Technology Inc. DS21755B-page 11 TC646B/TC648B/TC649B 12V start-up timer is activated again. If pulses are not detected at the SENSE pin during this additional period, the FAULT output will go low to indicate that a fan fault condition has occurred. See Section 4.7, "FAULT/OTF Output", for more details. VDD FAN 4.4 D TC646B VOUT TC648B TC649B GND G S PWM Frequency & Duty Cycle Control (CF & VIN Pins) QDRIVE FIGURE 4-2: PWM Fan Drive. By modulating the voltage applied to the gate of the MOSFET (QDRIVE), the voltage that is applied to the fan is also modulated. When the VOUT pulse is high, the gate of the MOSFET is turned on, pulling the voltage at the drain of QDRIVE to zero volts. This places the full 12V across the fan for the ton period of the pulse. When the duty cycle of the drive pulse is 100% (full on, ton = t), the fan will run at full speed. As the duty cycle is decreased (pulse on time "ton" is lowered), the fan will slow down proportionally. With the TC646B, TC648B and TC649B devices, the duty cycle is controlled by the VIN input and can also be terminated by the VAS input (auto-shutdown). This is described in more detail in Section 5.5, "Output Drive Device Selection". The frequency of the PWM pulse train is controlled by the C F pin. By attaching a capacitor to the C F pin, the frequency of the PWM pulse train can be set to the desired value. The typical PWM frequency for a 1.0 F capacitor is 30 Hz. The frequency can be adjusted by raising or lowering the value of the capacitor. The CF pin functions as a ramp generator. The voltage at this pin will ramp from 1.20V to 2.60V (typically) as a sawtooth waveform. An example of this is shown in Figure 4-3. 2.8 2.6 2.4 CF = 1 F VCMAX CF Voltage (V) 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0 20 40 60 80 100 VCMIN Time (msec) 4.3 Fan Start-up FIGURE 4-3: CF Pin Voltage. Often overlooked in fan speed control is the actual start-up control period. When starting a fan from a nonoperating condition (fan speed is zero revolutions per minute (RPM)), the desired PWM duty cycle or average fan voltage cannot be applied immediately. Since the fan is at a rest position, the fan's inertia must be overcome to get it started. The best way to accomplish this is to apply the full rated voltage to the fan for a minimum of one second. This will ensure that in all operating environments, the fan will start and operate properly. An example of the start-up timing is shown in Figure 1-1. A key feature of the TC646B/TC648B/TC649B devices is the start-up timer. When power is first applied to the device, or when the device is brought out of the shutdown/auto-shutdown modes of operation, the VOUT output will go to a high state for 32 PWM cycles (one second for CF = 1 F). This will drive the fan to full speed for this time frame. During the start-up period for the TC646B and TC649B devices, the SENSE pin is being monitored for fan pulses. If pulses are detected during this period, the fan speed controller will then move to PWM operation. If pulses are not detected during the start-up period, the The duty cycle of the PWM output is controlled by the voltage at the VIN input pin. The duty cycle of the PWM output is produced by comparing the voltage at the VIN pin to the voltage ramp at the CF pin. When the voltage at the VIN pin is 1.20V, the duty cycle will be 0%. When the voltage at the V IN pin is 2.60V, the PWM duty cycle will be 100% (these are both typical values). The VIN-to-PWM duty cycle relationship is shown in Figure 4-4. The lower value of 1.20V is referred to as "VCMIN" and the 2.60V threshold is referred to as "VCMAX". A calculation for duty cycle is shown in the equation below. The voltage range between VCMIN and VCMAX is characterized as "VCSPAN" and has a typical value of 1.4V, with minimum and maximum values of 1.3V and 1.5V, respectively. EQUATION PWM DUTY CYCLE (VIN - VCMIN) * 100 VCMAX - VCMIN Duty Cycle (%) = DS21755B-page 12 2003 Microchip Technology Inc. TC646B/TC648B/TC649B For the TC646B, TC648B and TC649B devices, the V IN pin is also used as the shutdown pin. The VSHDN and VREL threshold voltages are characterized in the "Electrical Characteristics Table" of Section 1.0. If the VIN pin voltage is pulled below the VSHDN threshold, the device will shut down (VOUT output goes to a low state, the FAULT/OTF pin is inactive). If the voltage on the VIN pin then rises above the release threshold (VREL), the device will go through a power-up sequence (assuming that the V IN voltage is also higher than the voltage at the VAS pin). The power-up sequence is shown later in the "Behavioral Algorithm Flowcharts" of Section 4.9. 100 90 80 When the device is in shutdown/auto-shutdown mode, the VOUT output is actively held low. The output can be varied from 0% (full off) to 100% duty cycle (full on). As previously discussed, the duty cycle of the VOUT output is controlled via the VIN input voltage and can be terminated based on the VAS voltage. A base current-limiting resistor is required when using a transistor as the external drive device in order to limit the amount of drive current that is drawn from the VOUT output. The VOUT output can be directly connected to the gate of an external MOSFET. One concern when doing this, though, is that the fast turn-off time of the fan drive MOSFET can cause a problem because the fan motor looks like an inductor. When the MOSFET is turned off quickly, the current in the fan wants to continue to flow in the same direction. This causes the voltage at the drain of the MOSFET to rise. If there aren't any clamp diodes internal to the fan, this voltage can rise above the drain-to-source voltage rating of the MOSFET. For this reason, an external clamp diode is suggested. This is shown in Figure 4-5. Duty Cycle (%) 70 60 50 40 30 20 10 0 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 VIN (V) FIGURE 4-4: Cycle (Typical). VIN Voltage vs. PWM Duty Clamp Diode FAN 4.5 Auto-Shutdown Mode (VAS) Q1 For the TC646B, TC648B and TC649B devices, pin 3 is the VAS pin and is used for setting the auto-shutdown threshold voltage. The auto-shutdown function provides a way to set a threshold voltage (temperature) at which the fan will be shut off. This way, if the temperature in the system reaches a threshold at which the fan(s) no longer needs to operate, the fan can be shutdown automatically. The voltage range for the VAS pin is the same as the voltage range for the VIN pin (1.20V to 2.60V). The voltage at the VAS pin is set in this range so that when the voltage at the VIN pin decreases below the voltage at the VAS pin (signifying that the threshold temperature has been reached), the VOUT output is shut off (goes to a low state). In auto-shutdown, the FAULT/OTF output is inactive (high-impedance). Auto-shutdown mode is exited when the VIN voltage exceeds the VAS voltage by the auto-shutdown hysteresis voltage (VHAS). Upon exiting auto-shutdown mode, the start-up timer is triggered and the device returns to normal operation. VOUT RSENSE GND Q1: N-Channel MOSFET FIGURE 4-5: Clamp Diode for Fan. 4.7 FAULT/OTF Output 4.6 VOUT Output (PWM Output) The VOUT output is a digital output designed for driving the base of a transistor or the gate of a MOSFET. The VOUT output is designed to be able to quickly raise the base current or the gate voltage of the external drive device to its final value. The FAULT/OTF output is an open-drain, active-low output. For the TC646B and TC649B devices, pin 6 is labeled as the FAULT output and indicates when a fan fault condition has occurred. For the TC646B device, the FAULT output also indicates when an over-temperature (OTF) condition has occurred. For the TC648B device, pin 6 is the OTF output that indicates an overtemperature (OTF) condition has occurred. 2003 Microchip Technology Inc. DS21755B-page 13 TC646B/TC648B/TC649B For the TC646B and TC648B devices, an over-temperature condition is indicated when the VIN input reaches the V OTF threshold voltage (the VOTF threshold voltage is typically 20 mV higher than the VCMAX threshold and has 80 mV of hysteresis). This indicates that maximum cooling capacity has been reached (the fan is at full speed) and that an overheating situation can occur. When the voltage at the VIN input falls below the VOTF threshold voltage by the hysteresis value (VOTF-HYS), the FAULT/OTF output will return to the high state (a pull-up resistor is needed on the FAULT/OTF output). For the TC646B/TC649B devices, a fan fault condition is indicated when fan current pulses are no longer detected at the SENSE pin. Pulses at the SENSE pin indicate that the fan is spinning and conducting current. If pulses are not detected at the SENSE pin for 32 PWM cycles, the 3-cycle diagnostic timer is fired. This means that the VOUT output is high for 3 PWM cycles. If pulses are detected in this 3-cycle period, normal PWM operation is resumed and no fan fault is indicated. If no pulses are detected in the 3-cycle period, the start-up timer is activated and the VOUT output is driven high for 32 PWM cycles. If pulses are detected during this time-frame, normal PWM operation is resumed. If no pulses are detected during this timeperiod, a fan fault condition exists and the FAULT output is pulled low. During a fan fault condition, the FAULT output will remain low until the fault condition has been removed. During this time, the VOUT output is driven high continuously to attempt to restart the fan and the SENSE pin is monitored for fan pulses. If a minimum of 16 pulses are detected at the SENSE input over a 32 cycle timeperiod (one second for C F = 1.0 F), the fan fault condition no longer exists. Therefore, The FAULT output is released and the V OUT output returns to normal PWM operation, as dictated by the VIN and VAS inputs. If the VIN voltage is pulled below the VSHDN level during a fan fault condition, the FAULT output will be released and the VOUT output will be shutdown (VOUT = 0V). If the VIN voltage then increases above the VREL threshold and is above the VAS voltage, the device will go through the normal start-up routine. If, during a fan fault condition, the voltage at the V IN pin drops below the VAS voltage level, the TC646B/ TC649B device will continue to hold the FAULT line low and drive the V OUT output to 100% duty cycle. If the fan fault condition is then removed, the FAULT output will be released and the TC646B/TC649B device will enter auto-shutdown mode until the V IN voltage is brought above the VAS voltage by the auto-shutdown hysteresis value (VHAS). The TC646B/TC649B device will then resume normal PWM mode operation. The sink current capability of the FAULT output is listed in the "Electrical Characteristics Table" of Section 1.0. 4.8 Sensing Fan Operation (SENSE) The SENSE input is an analog input used to monitor the fan's operation (the TC648B device does not incorporate the fan sensing feature). It does this by sensing fan current pulses that represent fan rotation. When a fan rotates, commutation of the fan current occurs as the fan poles pass the armatures of the motor. The commutation of the fan current makes the current waveshape appear as pulses. There are two typical current waveforms of brushless DC fan motors, illustrated in Figures 4-6 and 4-7. FIGURE 4-6: Fan Current With DC Offset And Positive Commutation Current. FIGURE 4-7: Fan Current With Commutation Pulses To Zero. DS21755B-page 14 2003 Microchip Technology Inc. TC646B/TC648B/TC649B The SENSE pin senses positive voltage pulses that have an amplitude of 70 mV (typical value). Each time a pulse is detected, the missing pulse detector timer (tMP) is reset. As previously stated, if the missing pulse detector timer reaches the time for 32 cycles, the loop for diagnosing a fan fault is engaged (diagnostic timer, then the start-up timer). Both of the fan current waveshapes shown in Figures 4-6 and 4-7 can be sensed with the sensing scheme shown in Figure 4-8. The initial pulse blanker is also implemented to stop false sensing of fan current pulses. When a fan is in a locked rotor condition, the fan current no longer commutates, it simply flows through one fan winding and is a DC current. When a fan is in a locked rotor condition and the TC646B/TC649B device is in PWM mode, it will see one current pulse each time the VOUT output is turned on. The initial pulse blanker allows the TC646B/TC649B device to ignore this pulse and recognize that the fan is in a fault condition. 4.9 FAN TC64XB VOUT SENSE GND CSENSE (0.1 F typical) RSENSE Behavioral Algorithms The behavioral algorithms for the TC646B/TC649B and TC648B devices are shown in Figure 4-9 and Figure 4-10, respectively. The behavioral algorithms show the step-by-step decision-making process for the fan speed controller operation. The TC646B and TC649B devices are very similar with one exception: the TC649B device does not implement the over-temperature portion of the algorithm. RISO FIGURE 4-8: Current. Sensing Scheme For Fan The fan current flowing through RSENSE generates a voltage that is proportional to the current. The CSENSE capacitor removes any DC portion of the voltage across R SENSE and presents only the voltage pulse portion to the SENSE pin of the TC646B/TC649B devices. The RSENSE and CSENSE values need to be selected so that the voltage pulse provided to the SENSE pin is 70 mV (typical) in amplitude. Be sure to check the sense pulse amplitude over all operating conditions (duty cycles) as the current pulse amplitude will vary with duty cycle. See Section 5.0, "Applications Information", for more details on selecting values for RSENSE and CSENSE. Key features of the SENSE pin circuitry are an initial blanking period after every VOUT pulse and an initial pulse blanker. The TC646B/TC649B sense circuitry has a blanking period that occurs at the turn-on of each VOUT pulse. During this blanking period, the sense circuitry ignores any pulse information that is seen at the SENSE pin input. This stops the TC646B/TC649B device from falsely sensing a current pulse that is due to the fan drive device turn-on. 2003 Microchip Technology Inc. DS21755B-page 15 TC646B/TC648B/TC649B Power-Up Normal Operation Power-on Reset FAULT = 1 Yes VIN < VSHDN? No Clear Missing Pulse Detector Shutdown VOUT = 0 VIN > VREL ? Yes Yes No Yes VIN < VSHDN? No Yes VIN < VAS? No No Yes Auto Shutdown VOUT = 0 Shutdown VOUT = 0 VIN > VREL? Yes Power-Up No VIN < VAS? No AutoShutdown VOUT = 0 VIN> (VAS+ VHAS) VIN > No (VAS + VHAS) Yes FAULT = 0 VIN > VOTF? Hot Start Fire Start-up Timer (1 sec) Fire Start-up Timer (1 sec) Yes No VOUT Proportional to VIN Hot Start TC646B Only Fan Pulse Detected? Yes No Yes Yes Normal Operation Fan Pulse Detected? No Fan Fault Fan Pulse Detected? No No M.P.D. Expired? Yes Fire Diagnostic Timer (100 msec) No Fire Start-up Timer (1 sec) Fan Fault Yes FAULT = Low, VOUT = High Fan Pulse Detected? Yes Yes Fan Pulse Detected? No Fan Fault VIN < VSHDN? No Shutdown VOUT = 0 No No 16 Pulses Detected? Yes Normal Operation VIN > VREL? Yes Power-Up FIGURE 4-9: TC646B/TC649B Behavioral Algorithm. DS21755B-page 16 2003 Microchip Technology Inc. TC646B/TC648B/TC649B Power-Up Normal Operation Power-on Reset OTF = 1 VOUT Proportional to VIN VAS = 0V No Yes Minimum Speed Mode Yes VIN > VOTF ? No OTF = 0 Yes VIN < VAS? No AutoShutdown VOUT = 0 VIN > (VAS+ VHAS) Yes Fire Start-up Timer (1 sec) Normal Operation No Auto Shutdown VOUT = 0 Yes OTF = 1 VIN < VAS? No Minimum Speed Mode VOUT = 0 Yes VIN = 0V No No VIN > 1.20V No VIN > 1.20V Yes VOUT = 0 Power-Up Yes VOUT Proportional to VIN Yes VIN > VOTF? No OTF = 0 OTF = 1 FIGURE 4-10: TC648B Behavioral Algorithm. 2003 Microchip Technology Inc. DS21755B-page 17 TC646B/TC648B/TC649B 5.0 5.1 APPLICATIONS INFORMATION Setting the PWM Frequency One of the simplest ways of sensing temperature over a given range is to use a thermistor. By using a NTC thermistor, as shown in Figure 5-1, a temperaturevariant voltage can be created. VDD IDIV The PWM frequency of the VOUT output is set by the capacitor value attached to the CF pin. The PWM frequency will be 30 Hz (typical) for a 1 F capacitor. The relationship between frequency and capacitor value is linear, making alternate frequency selections easy. As stated in previous sections, the PWM frequency should be kept in the range of 15 Hz to 35 Hz. This will eliminate the possibility of having audible frequencies when varying the duty cycle of the fan drive. A very important factor to consider when selecting the PWM frequency for the TC646B/TC648B/TC649B devices is the RPM rating of the selected fan and the minimum duty cycle that you will be operating at. For fans that have a full-speed rating of 3000 RPM or less, it is desirable to use a lower PWM frequency. A lower PWM frequency allows for a longer time-period to monitor the fan current pulses. The goal is to be able to monitor at least two fan current pulses during the ontime of the VOUT output. Example: The system design requirement is to operate the fan at 50% duty cycle when ambient temperatures are below 20C. The fan full-speed RPM rating is 3000 RPM and has four current pulses per rotation. At 50% duty cycle, the fan will be operating at approximately 1500 RPM. RT R1 VIN R2 FIGURE 5-1: Circuit. Temperature Sensing EQUATION Time for one revolution (msec.) = 60 x 1000 = 40 ----------------------1500 If one fan revolution occurs in 40 msec, each fan pulse occurs 10 msec apart. In order to detect two fan current pulses, the on-time of the VOUT pulse must be at least 20 msec. With the duty cycle at 50%, the total period of one cycle must be at least 40 msec, which makes the PWM frequency 25 Hz. For this example, a PWM frequency of 20 Hz is recommended. This would define a CF capacitor value of 1.5 F. Figure 5-1 represents a temperature-dependent, voltage divider circuit. RT is a conventional NTC thermistor, R 1 and R2 are standard resistors. R1 and RT form a parallel resistor combination that will be referred to as RTEMP (RTEMP = R1 * RT / R1 + RT). As the temperature increases, the value of RT decreases and the value of RTEMP will decrease with it. Accordingly, the voltage at VIN increases as temperature increases, giving the desired relationship for the VIN input. R1 helps to linearize the response of the SENSE network and aids in obtaining the proper VIN voltages over the desired temperature range. An example of this is shown in Figure 5-2. If less current draw from VDD is desired, a larger value thermistor should be chosen. The voltage at the VIN pin can also be generated by a voltage output temperature sensor device. The key is to get the desired VIN voltage-to-system (or component) temperature relationship. The following equations apply to the circuit in Figure 5-1. 5.2 Temperature Sensor Design EQUATION V DD x R 2 V ( T1 ) = --------------------------------------------R TEMP ( T1 ) + R 2 V DD x R 2 V ( T2 ) = --------------------------------------------R TEMP ( T2 ) + R 2 In order to solve for the values of R1, R2, VIN and the temperatures at which they are to occur, need to be selected. The variables T1 and T2 represent the selected temperatures. The value of the thermistor at these two temperatures can be found in the thermistor As discussed in previous sections, the VIN analog input has a range of 1.20V to 2.60V (typical), which represents a duty cycle range on the VOUT output of 0% to 100%, respectively. The VIN voltages can be thought of as representing temperatures. The 1.20V level is the low temperature at which the system requires very little cooling. The 2.60V level is the high temperature, for which the system needs maximum cooling capability (100% fan speed). DS21755B-page 18 2003 Microchip Technology Inc. TC646B/TC648B/TC649B data sheet. With the values for the thermistor and the values for VIN, you now have two equations from which the values for R 1 and R 2 can be found. Example: The following design goals are desired: * Duty Cycle = 50% (VIN = 1.90V) with Temperature (T1) = 30C * Duty Cycle = 100% (VIN = 2.60V) with Temperature (T2) = 60C Using a 100 k thermistor (25C value), we look up the thermistor values at the desired temperatures: * RT (T1) = 79428 @ 30C * RT (T2) = 22593 @ 60C Substituting these numbers into the given equations produces the following numbers for R 1 and R 2. * R1 = 34.8 k * R2 = 14.7 k 140 Network Resistance (k ) 120 100 80 60 40 20 0 20 30 40 50 60 70 80 90 RTEMP NTC Thermistor 100 k @ 25C VIN Voltage 4.000 3.500 3.000 2.500 2.000 1.500 1.000 0.500 0.000 100 VIN (V) 5.4 FanSense Network (RSENSE and CSENSE) The SENSE network (comprised of RSENSE and CSENSE) allows the TC646B and TC649B devices to detect commutation of the fan motor. RSENSE converts the fan current into a voltage. CSENSE AC couples this voltage signal to the SENSE pin. The goal of the SENSE network is to provide a voltage pulse to the SENSE pin that has a minimum amplitude of 90 mV. This will ensure that the current pulse caused by the fan commutation is recognized by the TC646B/ TC649B device. A 0.1 F ceramic capacitor is recommended for CSENSE. Smaller values will require that larger sense resistors be used. Using a 0.1 F capacitor results in reasonable values for RSENSE. Figure 5-3 illustrates a typical SENSE network. FAN RISO 715 VOUT SENSE CSENSE (0.1 F typical) RSENSE Temperature (C) Note: See Table 5-1 for R SENSE values. FIGURE 5-2: How Thermistor Resistance, VIN, and RTEMP Vary With Temperature. Figure 5-2 graphs RT, RTEMP (R1 in parallel with RT) and VIN, versus temperature for the example shown above. FIGURE 5-3: Typical Sense Network. 5.3 Thermistor Selection As with any component, there are a number of sources for thermistors. A listing of companies that manufacture thermistors can be found at www.temperatures.com/ thermivendors.html. This website lists over forty suppliers of thermistor products. A brief list is shown here: Thermometrics(R) Ametherm (R) - Quality ThermistorTM Sensor ScientificTM Vishay(R) muRata(R) U.S. SensorTM Advanced Thermal ProductsTM The required value of RSENSE will change with the current rating of the fan and the fan current waveshape. A key point is that the current rating of the fan specified by the manufacturer may be a worst-case rating, with the actual current drawn by the fan being lower than this rating. For the purposes of setting the value for RSENSE, the operating fan current should be measured to get the nominal value. This can be done by using an oscilloscope current probe or using a voltage probe with a low-value resistor (0.5). Another good tool for this exercise is the TC642 Evaluation Board. This board allows the RSENSE and CSENSE values to be easily changed while allowing the voltage waveforms to be monitored to ensure the proper levels are being reached. Table 5-1 shows values of RSENSE according to the nominal operating current of the fan. The fan currents are average values. If the fan current falls between two of the values listed, use the higher resistor value. 2003 Microchip Technology Inc. DS21755B-page 19 TC646B/TC648B/TC649B TABLE 5-1: FAN CURRENT VS. R SENSE RSENSE () 9.1 4.7 3.0 2.4 2.0 1.8 1.5 1.3 1.2 1.0 Nominal Fan Current (mA) 50 100 150 200 250 300 350 400 450 500 Another important factor to consider when selecting the R SENSE value is the fan current value during a lockedrotor condition. When a fan is in a locked-rotor condition (fan blades are stopped even though power is being applied to the fan), the fan current can increase dramatically (often 2.5 to 3.0 times the normal operating fan current). This will effect the power rating of the R SENSE resistor selected. When selecting the fan for the application, the current draw of the fan during a locked-rotor condition should be considered. Especially if multiple fans are being used in the application. There are two main types of fan designs when looking at fan current draw during a locked-rotor condition. The first is a fan that will simply draw high DC currents when put into a locked-rotor condition. Many older fans were designed this way. An example of this is a fan that draws an average current of 100 mA during normal operation. In a locked-rotor condition, this fan will draw 250 mA of average current. For this design, the R SENSE power rating must be sized to handle the 250 mA condition. The fan bias supply must also take this into account. The second style design, which represents many of the newer fan designs today, acts to limit the current in a locked-rotor condition by going into a pulse mode of operation. An example of the fan current waveshape for this style fan is shown in Figure 5-5. The fan represented in Figure 5-5 is a Panasonic(R), 12V, 220 mA fan. During the on-time of the waveform, the fan current is peaking up to 550 mA. Due to the pulse mode operation, the actual RMS current of the fan is very near the 220 mA rating. Because of this, the power rating for the R SENSE resistor does not have to be oversized for this application. The values listed in Table 5-1 are for fans that have the fan current waveshape shown in Figure 4-7. With this waveshape, the average fan current is closer to the peak value, which requires the resistor value to be higher. When using a fan that has the fan current waveshape shown in Figure 4-6, the resistor value can often be decreased since the current peaks are higher than the average and it is the AC portion of the voltage that gets coupled to the SENSE pin. The key point when selecting an RSENSE value is to try to minimize the value in order to minimize the power dissipation in the resistor. In order to do this, it is critical to know the waveshape of the fan current and not just the average value. Figure 5-4 shows some typical waveforms for the fan current and the voltage at the SENSE pin. FIGURE 5-4: Typical Fan Current and SENSE Pin Waveforms. DS21755B-page 20 2003 Microchip Technology Inc. TC646B/TC648B/TC649B FIGURE 5-5: Fan Current During a Locked Rotor Condition. The following is recommended: * Ask how the fan is designed. If the fan has clamp diodes internally, this problem will not be seen. If the fan does not have internal clamp diodes, it is a good idea to install one externally (Figure 5-6). Putting a resistor between VOUT and the gate of the MOSFET will also help slow down the turn-off and limit this condition. 5.5 Output Drive Device Selection The TC646B/TC648B/TC649B is designed to drive an external NPN transistor or N-channel MOSFET as the fan speed modulating element. These two arrangements are shown in Figure 5-7. For lower-current fans, NPN transistors are a very economical choice for the fan drive device. It is recommended that, for higher current fans (300 mA and above), MOSFETs be used as the fan drive device. Table 5-2 provides some possible part numbers for use as the fan drive element. When using a NPN transistor as the fan drive element, a base current-limiting resistor must be used. This is shown in Figure 5-7. When using MOSFETs as the fan drive element, it is very easy to turn the MOSFETs on and off at very high rates. Because the gate capacitances of these small MOSFETs are very low, the TC646B/TC648B/TC649B can charge and discharge them very quickly, leading to very fast edges. Of key concern is the turn-off edge of the MOSFET. Since the fan motor winding is essentially an inductor, once the MOSFET is turned off the current that was flowing through the motor wants to continue to flow. If the fan does not have internal clamp diodes around the windings of the motor, there is no path for this current to flow through and the voltage at the drain of the MOSFET may rise until the drain-to-source rating of the MOSFET is exceeded. This will most likely cause the MOSFET to go into avalanche mode. Since there is very little energy in this occurrence, it will probably not fail the device, but it would be a long-term reliability issue. FAN VOUT Q1 RSENSE GND Q1: N-Channel MOSFET FIGURE 5-6: Off. Clamp Diode For Fan Turn- 2003 Microchip Technology Inc. DS21755B-page 21 TC646B/TC648B/TC649B Fan Bias Fan Bias FAN FAN VOUT RBASE Q1 VOUT Q1 RSENSE RSENSE GND a) Single Bipolar Transistor GND b) N-Channel MOSFET FIGURE 5-7: TABLE 5-2: Device MMBT2222A MPS2222A MPS6602 SI2302 MGSF1N02E SI4410 SI2308 Note 1: 2: Output Drive Device Configurations. FAN DRIVE DEVICE SELECTION TABLE (NOTE 2) Package SOT-23 TO-92 TO-92 SOT-23 SOT-23 SO-8 SOT-23 Max Vbe sat / Vgs(V) 1.2 1.2 1.2 2.5 2.5 4.5 4.5 Min hfe 50 50 50 NA NA NA NA VCE/VDS (V) 40 40 40 20 20 30 60 Fan Current (mA) 150 150 500 500 500 1000 500 Suggested Rbase () 800 800 301 Note 1 Note 1 Note 1 Note 1 A series gate resistor may be used in order to control the MOSFET turn-on and turn-off times. These drive devices are suggestions only. Fan currents listed are for individual fans. 5.6 Bias Supply Bypassing and Noise Filtering 5.7 Design Example/Typical Application The bias supply (VDD) for the TC646B/TC648B/ TC649B devices should be bypassed with a 1.0 F ceramic capacitor. This capacitor will help supply the peak currents that are required to drive the base/gate of the external fan drive devices. As the VIN pin controls the duty cycle in a linear fashion, any noise on this pin can cause duty cycle jittering. For this reason, the VIN pin should be bypassed with a 0.01 F capacitor. In order to keep fan noise off of the TC646B/TC648B/ TC649B device ground, individual ground returns for the TC646B/TC648B/TC649B and the low side of the fan current sense resistor should be used. The system has been designed with the following components and criteria: System inlet air ambient temperature ranges from 0C to 50C. At 20C, system cooling is no longer required, so the fan is to be turned off. Prior to turn-off, the fan should be run at 40% of its full fan speed. Full fan speed should be reached when the ambient air is 40C. The system has a surface mount, NTC-style thermistor in a 1206 package. The thermistor is mounted on a daughtercard that is directly in the inlet air stream. The thermistor is a NTC, 100 k @ 25C, Thermometrics(R) part number NHQ104B425R5. The given Beta for the thermistor is 4250. The system bias voltage to run the fan controller is 5V, while the fan voltage is 12V. DS21755B-page 22 2003 Microchip Technology Inc. TC646B/TC648B/TC649B The fan used in the system is a Panasonic(R), Panaflo(R)series fan, model number FBA06T12H. A fault indication is desired when the fan is in a lockedrotor condition. This signal is used to indicate to the system that cooling is not available and a warning should be issued to the user. No fault indication from the fan controller is necessary for an over-temperature condition as this is being reported elsewhere. Step 1: Gathering Information. The first step in the design process is to gather the needed data on the fan and thermistor. For the fan, it is also a good idea to look at the fan current waveform, as indicated earlier in the data sheet. Fan Information: Panasonic number: FBA06T12H - Voltage = 12V - Current = 145 mA (data sheet number) FIGURE 5-9: Fan Current. FBA06T12H Locked-Rotor From Figure 5-9, it is seen that in a locked-rotor fault condition, the fan goes into a pulsed current mode of operation. During this mode, when the fan is conducting current, the peak current value is 360 mA for periods of 200 msec. This is significantly higher than the average full fan speed current shown in Figure 5-8. However, because of the pulse mode, the average fan current in a locked-rotor condition is lower and was measured at 68 mA. The RMS current during this mode, which is necessary for current sense resistor (RSENSE) value selection, was measured at 154 mA. This is slightly higher than the RMS value during full fan speed operation. FIGURE 5-8: Waveform. FBA06T12H Fan Current Thermistor Information: Thermometrics part number: NHQ104B425R5 - Resistance Value: 100 k @ 25C - Beta Value (): 4250 From this information, the thermistor values at 20C and 40C must be found. This information is needed in order to select the proper resistor values for R1 and R2 (see Figure 5-13), which sets the VIN voltage. The equation for determining the thermistor values is shown below: From the waveform in Figure 5-8, the fan current has an average value of 120 mA, with peaks up to 150 mA. This information will help in the selection of the RSENSE and CSENSE values later on. Also of interest for the RSENSE selection value is what the fan current does in a locked-rotor condition. EQUATION ( TO - T ) R T = R TO exp -----------------------T * TO RT0 is the thermistor value at 25C. T0 is 298.15 and T is the temperature of interest. All temperatures are in degrees kelvin. Using this equation, the values for the thermistor are found to be: - RT (20C) = 127,462 - RT (40C) = 50,520 2003 Microchip Technology Inc. DS21755B-page 23 TC646B/TC648B/TC649B Step 2: Selecting the Fan Controller. The requirements for the fan controller are that it have auto-shutdown capability at 20C and also indicate a fan fault condition. No over-temperature indication is necessary. From these specifications, the proper selection is the TC649B device. Step 3: Setting the PWM Frequency. The fan is rated at 4200 RPM with a 12V input. The goal is to run to a 40% duty cycle (roughly 40% fan speed), which equates to approximately 1700 RPM. At 1700 RPM, one full fan revolution occurs every 35 msec. The fan being used is a four-pole fan that gives four current pulses per revolution. With this information, and viewing test results at 40% duty cycle, two fan current pulses were always seen during the PWM on time with a PWM frequency of 30 Hz. For this reason, the CF value is selected to be 1.0 F. Step 4: Setting the VIN Voltage. From the design criteria, the desired duty cycle at 20C is 40% and full fan speed should be reached at 40C. Based on a VIN voltage range of 1.20V to 2.60V, which represents 0% to 100% duty cycle, the 40% duty cycle voltage can be found using the following equation: Using standard 1% resistor values, the selected R1 and R 2 values are: - R1 = 237 k - R2 = 45.3 k A graph of the VIN voltage, thermistor resistance and RTEMP resistance versus temperature for this configuration is shown in Figure 5-10. 400 350 5.00 4.50 VIN 4.00 3.50 Network Resistance (k ) 300 250 200 150 100 50 0 0 10 20 30 40 50 2.50 NTC Thermistor 100 k @ 25C 2.00 1.50 1.00 RTEMP 60 70 80 90 0.50 0.00 Temperature (C) FIGURE 5-10: Thermistor Resistance, VIN and RTEMP vs. Temperature Step 5: Setting the Auto-Shutdown Voltage (VAS). Setting the voltage for the auto-shutdown is done using a simple resistor voltage divider. The criteria for the voltage divider in this design is that it draw no more than 100 A of current. The required auto-shutdown voltage was determined earlier in the selection of the VIN voltage at 40% duty cycle, since this was also set at the temperature that auto-shutdown is to occur (20C). - VAS = 1.76V Given this desired setpoint and knowing the desired divider current, the following equations can be used to solve for the resistor values for R3 and R4: EQUATION VIN = (DC * 1.4V) + 1.20V DC = Desired Duty Cycle Using the above equation, the VIN values are calculated to be: - VIN (40%) = 1.76V - VIN (100%) = 2.60V Using these values along with the thermistor resistance values calculated earlier, the R 1 and R2 resistor values can now be calculated using the following equation: EQUATION V DD x R 2 V ( T1 ) = ----------------------------------------R TEMP ( T1 ) + R 2 V DD x R 2 V ( T2 ) = ----------------------------------------R TEMP ( T2 ) + R 2 RTEMP is the parallel combination of R 1 and the thermistor. V(T1) represents the VIN voltage at 20C and V(T2) represents the VIN voltage at 40C. Solving the equations simultaneously yields the following values (VDD = 5V): - R1 = 238,455 - R2 = 45,161 EQUATION IDIV = VAS = 5V R3 + R 4 5V * R4 R3 + R 4 Using the equations above, the resistor values for R3 and R4 are found to be: - R3 = 32.4 k - R4 = 17.6 k Using standard 1% resistor values yields the following values: - R3 = 32.4 k - R4 = 17.8 k DS21755B-page 24 2003 Microchip Technology Inc. VIN (V) 3.00 TC646B/TC648B/TC649B Step 6: Selecting the Fan Drive Device (Q 1). Since the fan operating current is below 200 mA, a transistor or MOSFET can be used as the fan drive device. In order to reduce component count and current draw, the drive device for this design is chosen to be a N-channel MOSFET. Selecting from Table 5-2, there are two MOSFETs that are good choices, the MGSF1N02E and the SI2302. These devices have the same pinout and are interchangeable for this design. Step 7: Selecting the R SENSE and CSENSE Values. The goal again for selecting these values is to ensure that the signal at the SENSE pin is 90 mV in amplitude under all operating conditions. This will ensure that the pulses are detected by the TC649B device and that the fan operation is detected. The fan current waveform is shown in Figure 5-8, and as discussed previously, with a waveform of this shape, the current sense resistor values shown in Table 5-1 are good reference values. Given the average fan operating current was measured to be 120 mA, this falls between two of the values listed in the table. For reference purposes, both values have been tested and these results are shown in Figures 5-11 (4.7) and 5-12 (3.0). The selected CSENSE value is 0.1 F, as this provides the appropriate coupling of the voltage to the SENSE pin. FIGURE 5-12: SENSE pin voltage with 3.0 sense resistor. Since the 3.0 value of sense resistor provides the proper voltage to the SENSE pin, it is the correct choice for this solution as it will also provide the lowest power dissipation and the maximum amount of voltage to the fan. Using the RMS fan current which was measured previously, the power dissipation in the resistor during a fan fault condition is 71 mW (Irms2 * RSENSE). This number will set the wattage rating of the resistor that is selected. The selected value will vary depending upon the derating guidelines that are used. Now that all the values have been selected, the schematic representation of this design can be seen in Figure 5-13. FIGURE 5-11: SENSE pin voltage with 4.7 sense resistor. 2003 Microchip Technology Inc. DS21755B-page 25 TC646B/TC648B/TC649B +5V R1 237 k Thermometrics 100 k @25C NHQ104B425R5 CB 0.01 F 1V IN (R) +C 1.0 F 8 VDD FAULT 6 R5 10 k Panasonic(R) Fan 12V, 140 mA FBA06T12H VDD +12V R2 45.3k +5V R3 32.4 k 3V AS CB 0.01 F 2C F CF 1.0 F TC649B VOUT 7 Q1 SI2302 or MGSF1N02E CSENSE 0.1 F SENSE GND 4 5 RSENSE 3.0 R4 17.8 k FIGURE 5-13: Design Example Schematic. Bypass capacitor CVDD is added to the design to decouple the bias voltage. This is good to have, especially when using a MOSFET as the drive device. This helps to give a localized low-impedance source for the current required to charge the gate capacitance of Q1. Two other bypass capacitors (labeled as C B) were also added to decouple the V IN and VAS nodes. These were added simply to remove any noise present that might cause false triggerings or PWM jitter. R 5 is the pull-up resistor for the FAULT output. The value for this resistor is system-dependent. DS21755B-page 26 2003 Microchip Technology Inc. TC646B/TC648B/TC649B 6.0 6.1 PACKAGING INFORMATION Package Marking Information 8-Lead PDIP (300 mil) Example: XXXXXXXXX NNN YYWW TC646BCPA 025 0215 8-Lead SOIC (150 mil) Example: XXXXXX XXXYYWW NNN TC646B COA0215 025 8-Lead MSOP Example: XXXXXX YWWNNN TC646B 215025 Legend: XX...X Y YY WW NNN Customer specific information* Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week `01') Alphanumeric traceability code Note: In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line thus limiting the number of available characters for customer specific information. * Standard device marking consists of Microchip part number, year code, week code, and traceability code. 2003 Microchip Technology Inc. DS21755B-page 27 TC646B/TC648B/TC649B 8-Lead Plastic Dual In-line (PA) - 300 mil (PDIP) E1 D 2 n 1 E A A2 c L A1 eB B1 p B Number of Pins Pitch Top to Seating Plane Molded Package Thickness Base to Seating Plane Shoulder to Shoulder Width Molded Package Width Overall Length Tip to Seating Plane Lead Thickness Upper Lead Width Lower Lead Width Overall Row Spacing Mold Draft Angle Top Mold Draft Angle Bottom * Controlling Parameter Significant Characteristic Units Dimension Limits n p A A2 A1 E E1 D L c B1 B eB MIN INCHES* NOM 8 .100 .155 .130 .313 .250 .373 .130 .012 .058 .018 .370 10 10 MAX MIN .140 .115 .015 .300 .240 .360 .125 .008 .045 .014 .310 5 5 .170 .145 .325 .260 .385 .135 .015 .070 .022 .430 15 15 MILLIMETERS NOM 8 2.54 3.56 3.94 2.92 3.30 0.38 7.62 7.94 6.10 6.35 9.14 9.46 3.18 3.30 0.20 0.29 1.14 1.46 0.36 0.46 7.87 9.40 5 10 5 10 MAX 4.32 3.68 8.26 6.60 9.78 3.43 0.38 1.78 0.56 10.92 15 15 Notes: Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" (0.254mm) per side. JEDEC Equivalent: MS-001 Drawing No. C04-018 DS21755B-page 28 2003 Microchip Technology Inc. TC646B/TC648B/TC649B 8-Lead Plastic Small Outline (OA) - Narrow, 150 mil (SOIC) E E1 p D 2 B n 1 h 45x c A A2 f L A1 Number of Pins Pitch Overall Height Molded Package Thickness Standoff Overall Width Molded Package Width Overall Length Chamfer Distance Foot Length Foot Angle Lead Thickness Lead Width Mold Draft Angle Top Mold Draft Angle Bottom * Controlling Parameter Significant Characteristic Units Dimension Limits n p A A2 A1 E E1 D h L f c B MIN .053 .052 .004 .228 .146 .189 .010 .019 0 .008 .013 0 0 INCHES* NOM 8 .050 .061 .056 .007 .237 .154 .193 .015 .025 4 .009 .017 12 12 MAX MIN .069 .061 .010 .244 .157 .197 .020 .030 8 .010 .020 15 15 MILLIMETERS NOM 8 1.27 1.35 1.55 1.32 1.42 0.10 0.18 5.79 6.02 3.71 3.91 4.80 4.90 0.25 0.38 0.48 0.62 0 4 0.20 0.23 0.33 0.42 0 12 0 12 MAX 1.75 1.55 0.25 6.20 3.99 5.00 0.51 0.76 8 0.25 0.51 15 15 Notes: Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" (0.254mm) per side. JEDEC Equivalent: MS-012 Drawing No. C04-057 2003 Microchip Technology Inc. DS21755B-page 29 TC646B/TC648B/TC649B 8-Lead Plastic Micro Small Outline Package (UA) (MSOP) E E1 p D 2 B n 1 A c A1 (F) A2 L 8 Number of Pins .026 BSC Pitch A .043 Overall Height A2 .030 .033 .037 Molded Package Thickness A1 .000 .006 Standoff E .193 TYP. Overall Width E1 .118 BSC Molded Package Width D .118 BSC Overall Length L .016 .024 .031 Foot Length Footprint (Reference) F .037 REF Foot Angle 0 8 c Lead Thickness .003 .006 .009 B .009 .012 .016 Lead Width 5 15 Mold Draft Angle Top 5 15 Mold Draft Angle Bottom *Controlling Parameter Notes: Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010" (0.254mm) per side. Units Dimension Limits n p MIN INCHES NOM MAX MIN MILLIMETERS* NOM 8 0.65 BSC 0.75 0.85 0.00 4.90 BSC 3.00 BSC 3.00 BSC 0.40 0.60 0.95 REF 0 0.08 0.22 5 5 - MAX 1.10 0.95 0.15 0.80 8 0.23 0.40 15 15 JEDEC Equivalent: MO-187 Drawing No. C04-111 DS21755B-page 30 2003 Microchip Technology Inc. TC646B/TC648B/TC649B 6.2 Taping Form Component Taping Orientation for 8-Pin MSOP Devices User Direction of Feed PIN 1 W P Standard Reel Component Orientation for 713 or TR Suffix Device Carrier Tape, Number of Components Per Reel and Reel Size: Package 8-Pin MSOP Carrier Width (W) 12 mm Pitch (P) 8 mm Part Per Full Reel 2500 Reel Size 13 in. Component Taping Orientation for 8-Pin SOIC Devices User Direction of Feed PIN 1 W P Standard Reel Component Orientation for 713 or TR Suffix Device Carrier Tape, Number of Components Per Reel and Reel Size: Package 8-Pin SOIC Carrier Width (W) 12 mm Pitch (P) 8 mm Part Per Full Reel 2500 Reel Size 13 in. 2003 Microchip Technology Inc. DS21755B-page 31 TC646B/TC648B/TC649B NOTES: DS21755B-page 32 2003 Microchip Technology Inc. TC646B/TC648B/TC649B PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO. Device X Temperature Range /XX Package Examples: a) b) c) d) a) b) c) d) a) b) c) d) Device: TC646B: PWM Fan Speed Controller with Fan Restart, Auto-Shutdown, Fan Fault and Over-Temp Detection TC648B: PWM Fan Speed Controller with AutoShutdown and Over-Temp Detection TC649B: PWM Fan Speed Controller with Fan Restart, Auto-Shutdown and Fan Fault Detection E = -40C to +85C TC646BEOA: SOIC package. TC646BEOA713: Tape and Reel, SOIC package. TC646BEPA: PDIP package. TC646BEUA: MSOP package. TC648BEOA: SOIC package. TC648BEPA: PDIP package. TC648BEUA: MSOP package. TC648BEUA713: Tape and Reel, MSOP package. TC649BEOA: SOIC package. TC649BEOATR: Tape and Reel, SOIC package. TC649BEPA: PDIP package. TC649BEUA: MSOP package Temperature Range: Package: OA PA UA 713 Plastic SOIC, (150 mil Body), 8-lead Plastic DIP (300 mil Body), 8-lead Plastic Micro Small Outline (MSOP), 8-lead Tape and Reel (SOIC and MSOP) (TC646B and TC648B only) TR = Tape and Reel (SOIC and MSOP) (TC649B only) = = = = Sales and Support Data Sheets Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recommended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following: 1. 2. 3. Your local Microchip sales office The Microchip Corporate Literature Center U.S. FAX: (480) 792-7277 The Microchip Worldwide Site (www.microchip.com) Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using. Customer Notification System Register on our web site (www.microchip.com/cn) to receive the most current information on our products. 2003 Microchip Technology Inc. DS21755B-page 33 TC646B/TC648B/TC649B NOTES: DS21755B-page 34 2003 Microchip Technology Inc. Note the following details of the code protection feature on Microchip devices: * * * Microchip products meet the specification contained in their particular Microchip Data Sheet. Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. Microchip is willing to work with the customer who is concerned about the integrity of their code. Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as "unbreakable." * * Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break microchip's code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Use of Microchip's products as critical components in life support systems is not authorized except with express written approval by Microchip. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, KEELOQ, MPLAB, PIC, PICmicro, PICSTART, PRO MATE and PowerSmart are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. FilterLab, microID, MXDEV, MXLAB, PICMASTER, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Accuron, Application Maestro, dsPIC, dsPICDEM, dsPICDEM.net, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, PICC, PICkit, PICDEM, PICDEM.net, PowerCal, PowerInfo, PowerMate, PowerTool, rfLAB, rfPIC, Select Mode, SmartSensor, SmartShunt, SmartTel and Total Endurance are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. Serialized Quick Turn Programming (SQTP) is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. (c) 2003, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. Microchip received QS-9000 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona in July 1999 and Mountain View, California in March 2002. The Company's quality system processes and procedures are QS-9000 compliant for its PICmicro(R) 8-bit MCUs, KEELOQ(R) code hopping devices, Serial EEPROMs, microperipherals, non-volatile memory and analog products. In addition, Microchip's quality system for the design and manufacture of development systems is ISO 9001 certified. DS21755B-page 35 2003 Microchip Technology Inc. M WORLDWIDE SALES AND SERVICE AMERICAS Corporate Office 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: 480-792-7627 Web Address: http://www.microchip.com ASIA/PACIFIC Australia Microchip Technology Australia Pty Ltd Marketing Support Division Suite 22, 41 Rawson Street Epping 2121, NSW Australia Tel: 61-2-9868-6733 Fax: 61-2-9868-6755 Japan Microchip Technology Japan K.K. Benex S-1 6F 3-18-20, Shinyokohama Kohoku-Ku, Yokohama-shi Kanagawa, 222-0033, Japan Tel: 81-45-471- 6166 Fax: 81-45-471-6122 Atlanta 3780 Mansell Road, Suite 130 Alpharetta, GA 30022 Tel: 770-640-0034 Fax: 770-640-0307 Korea Microchip Technology Korea 168-1, Youngbo Bldg. 3 Floor Samsung-Dong, Kangnam-Ku Seoul, Korea 135-882 Tel: 82-2-554-7200 Fax: 82-2-558-5934 China - Beijing Microchip Technology Consulting (Shanghai) Co., Ltd., Beijing Liaison Office Unit 915 Bei Hai Wan Tai Bldg. No. 6 Chaoyangmen Beidajie Beijing, 100027, No. China Tel: 86-10-85282100 Fax: 86-10-85282104 Boston 2 Lan Drive, Suite 120 Westford, MA 01886 Tel: 978-692-3848 Fax: 978-692-3821 Singapore Microchip Technology Singapore Pte Ltd. 200 Middle Road #07-02 Prime Centre Singapore, 188980 Tel: 65-6334-8870 Fax: 65-6334-8850 Chicago 333 Pierce Road, Suite 180 Itasca, IL 60143 Tel: 630-285-0071 Fax: 630-285-0075 China - Chengdu Microchip Technology Consulting (Shanghai) Co., Ltd., Chengdu Liaison Office Rm. 2401-2402, 24th Floor, Ming Xing Financial Tower No. 88 TIDU Street Chengdu 610016, China Tel: 86-28-86766200 Fax: 86-28-86766599 Taiwan Microchip Technology (Barbados) Inc., Taiwan Branch 11F-3, No. 207 Tung Hua North Road Taipei, 105, Taiwan Tel: 886-2-2717-7175 Fax: 886-2-2545-0139 Dallas 4570 Westgrove Drive, Suite 160 Addison, TX 75001 Tel: 972-818-7423 Fax: 972-818-2924 Detroit Tri-Atria Office Building 32255 Northwestern Highway, Suite 190 Farmington Hills, MI 48334 Tel: 248-538-2250 Fax: 248-538-2260 China - Fuzhou Microchip Technology Consulting (Shanghai) Co., Ltd., Fuzhou Liaison Office Unit 28F, World Trade Plaza No. 71 Wusi Road Fuzhou 350001, China Tel: 86-591-7503506 Fax: 86-591-7503521 EUROPE Austria Microchip Technology Austria GmbH Durisolstrasse 2 A-4600 Wels Austria Tel: 43-7242-2244-399 Fax: 43-7242-2244-393 Kokomo 2767 S. Albright Road Kokomo, IN 46902 Tel: 765-864-8360 Fax: 765-864-8387 China - Hong Kong SAR Microchip Technology Hongkong Ltd. Unit 901-6, Tower 2, Metroplaza 223 Hing Fong Road Kwai Fong, N.T., Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431 Los Angeles 18201 Von Karman, Suite 1090 Irvine, CA 92612 Tel: 949-263-1888 Fax: 949-263-1338 Denmark Microchip Technology Nordic ApS Regus Business Centre Lautrup hoj 1-3 Ballerup DK-2750 Denmark Tel: 45-4420-9895 Fax: 45-4420-9910 China - Shanghai Microchip Technology Consulting (Shanghai) Co., Ltd. Room 701, Bldg. B Far East International Plaza No. 317 Xian Xia Road Shanghai, 200051 Tel: 86-21-6275-5700 Fax: 86-21-6275-5060 Phoenix 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7966 Fax: 480-792-4338 France Microchip Technology SARL Parc d'Activite du Moulin de Massy 43 Rue du Saule Trapu Batiment A - ler Etage 91300 Massy, France Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79 San Jose Microchip Technology Inc. 2107 North First Street, Suite 590 San Jose, CA 95131 Tel: 408-436-7950 Fax: 408-436-7955 China - Shenzhen Microchip Technology Consulting (Shanghai) Co., Ltd., Shenzhen Liaison Office Rm. 1812, 18/F, Building A, United Plaza No. 5022 Binhe Road, Futian District Shenzhen 518033, China Tel: 86-755-82901380 Fax: 86-755-82966626 Toronto 6285 Northam Drive, Suite 108 Mississauga, Ontario L4V 1X5, Canada Tel: 905-673-0699 Fax: 905-673-6509 Germany Microchip Technology GmbH Steinheilstrasse 10 D-85737 Ismaning, Germany Tel: 49-89-627-144-0 Fax: 49-89-627-144-44 China - Qingdao Rm. B505A, Fullhope Plaza, No. 12 Hong Kong Central Rd. Qingdao 266071, China Tel: 86-532-5027355 Fax: 86-532-5027205 Italy Microchip Technology SRL Via Quasimodo, 12 20025 Legnano (MI) Milan, Italy Tel: 39-0331-742611 Fax: 39-0331-466781 India Microchip Technology Inc. India Liaison Office Marketing Support Division Divyasree Chambers 1 Floor, Wing A (A3/A4) No. 11, O'Shaugnessey Road Bangalore, 560 025, India Tel: 91-80-2290061 Fax: 91-80-2290062 United Kingdom Microchip Ltd. 505 Eskdale Road Winnersh Triangle Wokingham Berkshire, England RG41 5TU Tel: 44-118-921-5869 Fax: 44-118-921-5820 03/25/03 DS21755B-page 36 2003 Microchip Technology Inc. |
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