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FEATURES External Temperature Measurement with Remote Diode (Two Channels) On-Chip Temperature Sensor Interrupt and Over-Temperature Outputs Fault Tolerant Fan Control Brownout Detection LDCM Support System Management Bus (SMBus) Standby Mode to Minimize Power Consumption Limit Comparison of all Monitored Values APPLICATIONS Network Servers and Personal Computers Microprocessor-Based Office Equipment Test Equipment and Measuring Instruments
Low-Cost PC Temperature Monitor and Fan Control ASIC ADM1022
GENERAL DESCRIPTION
The ADM1022 is a low cost temperature monitor and fan controller for microprocessor-based systems. The temperature of one or two remote sensor diodes may be measured, allowing monitoring of processor temperature in single- or dual-processor systems. Measured values can be read out via a serial System Management Bus, and values for limit comparisons can be programmed in over the same serial bus. The ADM1022 also contains a DAC for fan speed control. Automatic hardware temperature trip points are provided and the fan will be driven to full speed if they are exceeded. Finally, the chip has two supply voltage monitors for brownout detection. The ADM1022's 3.0 V to 5.5 V supply voltage range, low supply current, and SMBus interface make it ideal for a wide range of applications. These include hardware monitoring and protection applications in personal computers, electronic test equipment and office electronics.
FUNCTIONAL BLOCK DIAGRAM
VCC VMON
ADD/NTEST_OUT RST1 RESET GENERATOR 1
ADM1022
SERIAL BUS INTERFACE
SDA SCL
RST2
VCC 20k
RESET GENERATOR 2
ANALOG OUTPUT REGISTER AND 8-BIT DAC ADDRESS POINTER REGISTER VALUE AND LIMIT REGISTERS LIMIT COMPARATORS ADC INTERRUPT STATUS REGISTERS INT MASK REGISTER MASK GATING CONFIGURATION REGISTER
FAN_SPD/NTEST_IN
MR BANDGAP TEMPERATURE SENSOR D1+ D1- D2+/GPI D2-/THERM ANALOG MULTIPLEXER
2.5V BANDGAP REFERENCE
INT
FAN_OFF
GND
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Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 (c) Analog Devices, Inc., 2000
ADM1022-SPECIFICATIONS (T = T
A
MIN
to TMAX, VCC = VMIN to VMAX, unless otherwise noted.)
Typ1 3.30 1.4 Max 5.5 2.6 3 2 5 3 Unit V mA C C C C C C A A ms V % % LSB LSB LSB mA mA V mV s ns s k V ms s V V IOUT = 3.0 mA ISINK = 1.2 mA VCC = VTH(MAX) Test Conditions
Parameter POWER SUPPLY Supply Voltage, VCC Supply Current, ICC TEMPERATURE-TO-DIGITAL CONVERTER Internal Sensor Accuracy Resolution External Diode Sensor Accuracy Resolution Remote Sensor Source Current Total Monitoring Cycle Time, tC ANALOG OUTPUT Output Voltage Range Total Unadjusted Error, TUE Full-Scale Error Zero Error Differential Nonlinearity, DNL Integral Nonlinearity Output Source Current Output Sink Current VOLTAGE MONITOR THRESHOLDS Reset Threshold, VMON, VCC Hysteresis MR INPUT MR Minimum Pulsewidth, tMR MR Glitch Immunity MR to RST2 Propagation Delay, tMD MR Pull-Up Resistance RESET OUTPUTS, RST1, RST2 Reset Output Voltage, VOL Reset Active Timeout Period, tRP VCC to Reset Delay, tD DIGITAL OUTPUT ADD/NTEST_OUT2 Output High Voltage, VOH Output Low Voltage, VOL OPEN-DRAIN DIGITAL OUTPUTS (INT, THERM, RST2, RST1) Output Low Voltage, VOL High Level Output Leakage Current, IOH OPEN-DRAIN SERIAL DATA BUS OUTPUT (SDA) Output Low Voltage, VOL High Level Output Leakage Current, IOH SERIAL BUS DIGITAL INPUTS (SCL, SDA) Input High Voltage, VIH Input Low Voltage, VIL Input Leakage Current Hysteresis
Min 3.0
Interface Inactive, ADC Active
1 1
TA = 85C, Tested at Wafer Sort TA = 85C, Tested at Wafer Sort High Level (D+ = D- +0.65 V) Low Level (D+ = D- +0.65 V)
60 3.5
1 90 5.5
130 7.5 200 2.5 5 3 1
0 1 2 1 2 1 2.85 2.925 50
IL = 2 mA No Load Monotonic by Design
3.00
Measured with VCC Falling
10 100 0.5 20
10
30 0.3
140
180 20
560
2.4 0.4
0.1
0.4 1
V A
IOUT = -3.0 mA VOUT = VCC
0.1
0.4 1
V A
IOUT = -3.0 mA VOUT = VCC
2.1 0.8 5 500
V (min) V (max) A mV
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Parameter DIGITAL INPUT LOGIC LEVELS (FAN_SPD/NTEST_IN, ADD/NTEST_OUT, MR, GPI) Input High Voltage, VIH Input Low Voltage, VIL DIGITAL INPUT LEAKAGE CURRENT (ALL DIGITAL INPUTS) Input High Current, IIH Input Low Current, IIL Input Capacitance, CIN SERIAL BUS TIMING3 Clock Frequency, fSCLK Glitch Immunity, tSW Bus Free Time, tBUF Start Setup Time, tSU:STA Start Hold Time, tHD:STA Stop Condition Setup Time, tSU:STO SCL Low Time, tLOW SCL High Time, tHIGH SCL, SDA Rise Time, tR SCL, SDA Fall Time, tF Data Setup Time, tSU:DAT Data Hold Time, tHD:DAT Min Typ Max Unit Test Conditions
2.2 0.8
V V
-1
-0.005 +0.005 5
+1
A A pF kHz ns s ns ns ns s s ns ns ns ns
VIN = VCC VIN = 0
400 50 1.3 600 600 600 1.3 0.6 300 300 100 300
See Figure 1 See Figure 1 See Figure 1 See Figure 1 See Figure 1 See Figure 1 See Figure 1 See Figure 1 See Figure 1 See Figure 1 See Figure 1 See Figure 1
NOTES 1 Typicals are at T A = 25C and represent most likely parametric norm. Standby current typ is measured with V CC = 3.3 V. 2 ADD is a three-state input that may be pulled high, low or left open-circuit. 3 Timing specifications are tested at logic levels of V IL = 0.8 V for a falling edge and V IH = 2.2 V for a rising edge. Specifications subject to change without notice.
tHD;STA tLOW
SCL
tR
tF
tHD;STA
SDA
tHD;DAT
tHIGH
tSU;DAT
tSU;STA
tSU;STO
tBUF
P S S P
Figure 1. Diagram for Serial Bus Timing
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ADM1022
ABSOLUTE MAXIMUM RATINGS*
Positive Supply Voltage (VCC) . . . . . . . . . . . . . . . . . . . . . 6.5 V Voltage On Digital Inputs Except Therm . . . -0.3 V to +6.5 V Voltage On Therm Pin . . . . . . . . . . . . .-0.3 V to VCC + 0.3 V Voltage on Any Other Input or Output Pin . . . . . . . . . . . . . . . . . . .-0.3 V to VCC + 0.3 V Input Current at Any Pin . . . . . . . . . . . . . . . . . . . . . . . 5 mA Package Input Current . . . . . . . . . . . . . . . . . . . . . . . 20 mA Maximum Junction Temperature (TJ max) . . . . . . . . . . 150C Storage Temperature Range . . . . . . . . . . . . -65C to +150C Lead Temperature, Soldering Vapor Phase 60 sec . . . . . . . . . . . . . . . . . . . . . . . . . . . 215C Infrared 15 sec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200C ESD Rating (Human Body Model) . . . . . . . . . . . . . . . 4000 V
*Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
THERMAL CHARACTERISTICS
16-Lead QSOP Package JA = 105C/W JA = 39C/W
ORDERING GUIDE
Model
Temperature Range
Package Description 16-Lead QSOP
Package Option RQ-16
ADM1022ARQ 0C to 85C
PIN CONFIGURATION
FAN_OFF 1 MR 2 RST1 3 GND 4
16 SDA 15 SCL 14 INT
13 ADD/NTEST_OUT TOP VIEW VCC 5 (Not to Scale) 12 D2+/GPI 11
ADM1022
VMON 6 RST2 7 FAN_SPD/NTEST_IN 8
D2-/THERM
10 D1+ 9
D1-
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PIN FUNCTION DESCRIPTION
Pin No. Mnemonic 1 FAN_OFF
Description Digital Output (Open-Drain) Fan Off Request. When asserted low this indicates a request to shut off the fan independent of the FAN_SPD output. When negated (output FET off) it indicates that the fan may be turned on. Digital Input, Manual Reset. A logic low on this input causes RST2 to be asserted. Once this input is negated that output will remain asserted for tRP. This input has an internal 20 k pull-up resistor. Leave unconnected if not used. Digital I/O (Open-Drain). This pin is asserted low while VCC remains below the reset threshold. It remains asserted for tRP after the reset condition is terminated. It is bidirectional so the ADM1022 can be optionally reset; external logic must be used to prevent system auxiliary reset from occurring when used as an input. GROUND. Power and Signal Ground. POWER 3.3 V. Power source and voltage monitor input for first reset generator. Analog Input. Voltage monitor input for second reset generator. Digital Output (Open-Drain). This pin is asserted low under any of the following conditions: - VMON or VCC remains below the reset threshold - while MR is held low - while RST1 is asserted. It remains asserted for tRP after the reset conditions are terminated. Analog Output/Test Input. An active-high input that enables NAND board-level connectivity testing. Refer to section on NAND testing. Used as an analog output for fan speed control when NAND test is not selected. Remote Thermal Diode Negative Input. This is the negative input (current sink) from the remote thermal diode. This also serves as the negative input into the A/D. Remote Thermal Diode Positive Input. This is the positive input (current source) from the remote thermal diode. This serves as the positive input into the A/D. Analog Input/Digital I/O (Open-Drain). Can be programmed as negative input for a second diode temperature sensor, or as a digital I/O pin. In this case it is an active low thermal overload output that indicates a violation of a temperature set point (over-temperature). Also acts as an input to provide external fan control. When this pin is pulled low by an external signal, a status bit is set and the fan speed is set to full on. Analog/Digital Input. Can be programmed as the positive input for a second diode sensor, or as a general-purpose logic input. In this case it can be programmed as an active high or active low input that sets Bit 4 of the Status Registers. This bit can only be reset by reading the status registers, provided GPI is in the inactive state. Digital I/O. The lowest order programmable bit of the SMBus Address. ADD is sampled at powerup and changing it while powered on will have no immediate effect. This pin also functions as an output when doing a NAND test. Digital Output (Open Drain), System Interrupt Output. This signal indicates a violation of a set trip point. The output is enabled when Bit 1 of the Configuration Register is set to 1. The default state is disabled. Digital Input SMBus Clock. Digital I/O (Open-Drain) SMBus Bidirectional Data.
2
MR
3
RST1
4 5 6 7
GND VCC VMON RST2
8
FAN_SPD/NTEST_IN
9 10 11
D1- D1+ D2-/THERM
12
D2+/GPI
13
ADD/NTEST_OUT
14
INT
15 16
SCL SDA
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ADM1022 -Typical Performance Characteristics
30 20
120 100 90
TEMPERATURE ERROR - C
10 DXP TO GND 0 -10 DXP TO VCC (5V) -20 -30 -40 -50 -60
READING
80 70 60 50 40 30 20 10 0
1
10 30 3.3 LEAKAGE RESISTANCE - M
100
0
10
20
60 70 80 30 40 50 MEASURED TEMPERATURE
90
100
110
Figure 2. Temperature Error vs. PC Leakage Resistance
Figure 5. Pentium(R) III Temperature Measurement vs. ADM1022 Reading
6
30 25
TEMPERATURE ERROR - C
5
TEMPERATURE ERROR - C
4 250mV p-p REMOTE 3 2
20
15 ERROR 10
1 100mV p-p REMOTE 0 -1
5 0 -5 1.0
50
500
5k
500k 50k FREQUENCY - Hz
5M
50M
2.2
3.2 4.7 10.0 14.0 7.0 DXP-DXN CAPACITANCE - nF
22.0
29.0
Figure 3. Temperature Error vs. Power Supply Noise Frequency
Figure 6. Temperature Error vs. Capacitance Between D+ and D-
25
80 70
100mV p-p
20
TEMPERATURE ERROR - C
15
SUPPLY CURRENT - A
60 50 40 VCC = 5V 30 20 10 VCC = 3V
10 50mV p-p 5
0
25mV p-p
-5 50 500 5k 50k 500k FREQUENCY - Hz 5M 50M
0 0 1k 5k 10k 25k 50k 75k 100k 250k 500k 750k 1M SCLK FREQUENCY - Hz
Figure 4. Temperature Error vs. Common-Mode Noise Frequency
Figure 7. Standby Current vs. Clock Frequency
Pentium is a registered trademark of Intel Corporation.
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10 9
TEMPERATURE ERROR - C
GENERAL DESCRIPTION
8 7 10mV SQ. WAVE 6 5 4 3 2 1 0 50 500 5k 100k 500k 50k FREQUENCY - Hz 5M 25M 50M
The ADM1022 is a low-cost temperature monitor and fan controller for microprocessor-based systems. The temperature of one or two remote sensor diodes may be measured, allowing monitoring of processor temperature in single- or dual-processor systems. The chip also contains an on-chip sensor to allow ambient temperature to be monitored. Measured values can be read out via a serial System Management Bus, and values for limit comparisons can be programmed in over the same serial bus. The ADM1022 also contains a DAC for fan speed control. Automatic hardware temperature trip points are provided for fault tolerant fan control and the fan will be driven to full speed if they are exceeded. Two interrupt outputs are provided, which will be asserted if the software or hardware limits are exceeded. Finally, the chip has two supply voltage monitors for brownout detection. These drive two reset pins, one of which is bidirectional. A manual reset input is also provided.
INTERNAL REGISTERS OF THE ADM1022
Figure 8. Temperature Error vs. Differential-Mode Noise Frequency
2.3
2.2 VDD = 5.5V
SUPPLY CURRENT - mA
A brief description of the ADM1022's principal internal registers is given below. More detailed information on the function of each register is given in Tables IV to IX. Configuration Register: Provides control and configuration. Address Pointer Register: This register contains the address that selects one of the other internal registers. When writing to the ADM1022, the first byte of data is always a register address, which is written to the Address Pointer Register.
2.1
2.0
1.9 VDD = 3.3V 1.8 VDD = 3.0V 1.7 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 TEMPERATURE - C
Interrupt (INT) Status Register: This register provides status of each Interrupt event. It is also mirrored by a second register at address 4Ch. Interrupt (INT) Mask Register: Allows masking of individual interrupt sources. Value and Limit Registers: The results of temperature measurements are stored in these registers, along with their limit values. Analog Output Register: The code controlling the analog output DAC is stored in this register.
SERIAL BUS INTERFACE
Figure 9. Standby Supply Current vs. Supply Voltage
400
POWER RESET TIMEOUT - ms
350 RST2 300
Control of the ADM1022 is carried out via the serial bus. The ADM1022 is connected to this bus as a slave device, under the control of a master device, e.g., the PIIX4. The ADM1022 has a 7-bit serial bus address. When the device is powered up, it will do so with a default serial bus address. The five MSBs of the address are set to 01011, the two LSBs are determined by the logical states of Pin 13 (ADD/NTEST_OUT). This is a three-state input that can be grounded, connected to VCC or left open-circuit to give three different addresses. The state of the ADD pin is only sampled at power-up, so changing ADD with power-on will have no effect until the device is powered off then on again.
Table I. ADD Pin Truth Table
250
200
150 RST1 100 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 TEMPERATURE - C
Figure 10. Power-up Reset vs. Temperature
ADD Pin GND No Connect VCC REV. 0 -7-
A1 1 0 0
A0 0 0 1
ADM1022
If ADD is left open-circuit the default address will be 0101100. The facility to make hardwired changes to A1 and A0 allows the user to avoid conflicts with other devices sharing the same serial bus; for example, if more than one ADM1022 is used in a system. The serial bus protocol operates as follows: 1. The master initiates data transfer by establishing a START condition, defined as a high-to-low transition on the serial data line SDA while the serial clock line SCL remains high. This indicates that an address/data stream will follow. All slave peripherals connected to the serial bus respond to the START condition, and shift in the next eight bits, consisting of a 7-bit address (MSB first) plus an R/W bit, which determines the direction of the data transfer, i.e., whether data will be written to or read from the slave device. The peripheral whose address corresponds to the transmitted address responds by pulling the data line low during the low period before the ninth clock pulse, known as the Acknowledge Bit. All other devices on the bus now remain idle while the selected device waits for data to be read from or written to it. If the R/W bit is a 0, the master will write to the slave device. If the R/W bit is a one, the master will read from the slave device. 2. Data is sent over the serial bus in sequences of nine clock pulses, eight bits of data followed by an Acknowledge Bit from the slave device. Transitions on the data line must occur during the low period of the clock signal and remain stable during the high period, as a low-to-high transition when the clock is high may be interpreted as a STOP signal. The number of data bytes that can be transmitted over the serial bus in a single READ or WRITE operation is limited only by what the master and slave devices can handle. 3. When all data bytes have been read or written, stop conditions are established. In WRITE mode, the master will pull the data line high during the 10th clock pulse to assert a STOP condition. In READ mode, the master device will override the acknowledge bit by pulling the data line high during the low period before the 9th clock pulse. This is known as No Acknowledge. The master will then take the data line low during the low period before the 10th clock pulse, then high during the 10th clock pulse to assert a STOP condition. Any number of bytes of data may be transferred over the serial bus in one operation, but it is not possible to mix read and write in one operation, because the type of operation is determined at the beginning and cannot subsequently be changed without starting a new operation. In the case of the ADM1022, write operations contain either one or two bytes, and read operations contain one byte, and perform the following functions: To write data to one of the device data registers or read data from it, the Address Pointer Register must be set so that the correct data register is addressed, then data can be written into that register or read from it. The first byte of a write operation always contains an address that is stored in the Address Pointer Register. If data is to be written to the device, then the write operation contains a second data byte that is written to the register selected by the address pointer register. This is illustrated in Figure 11a. The device address is sent over the bus followed by R/W set to 0. This is followed by two data bytes. The first data byte is the address of the internal data register to be written to, which is stored in the Address Pointer Register. The second data byte is the data to be written to the internal data register. When reading data from a register there are two possibilities: 1. If the ADM1022's Address Pointer Register value is unknown or not the desired value, it is first necessary to set it to the correct value before data can be read from the desired data register. This is done by performing a write to the ADM1022 as before, but only the data byte containing the register address is sent, as data is not to be written to the register. This is shown in Figure 11b. A read operation is then performed consisting of the serial bus address, R/W bit set to 1, followed by the data byte read from the data register. This is shown in Figure 11c. 2. If the Address Pointer Register is known to be already at the desired address, data can be read from the corresponding data register without first writing to the Address Pointer Register, so Figure 11b can be omitted. NOTES 1. Although it is possible to read a data byte from a data register without first writing to the Address Pointer Register, if the Address Pointer Register is already at the correct value, it is not possible to write data to a register without writing to the Address Pointer Register, because the first data byte of a write is always written to the Address Pointer Register. 2. In Figures 11a to 11c, the serial bus address is shown as the default value 01011(A1)(A0), where A1 and A0 are set by the three-state ADD pin. 3. The ADM1022 also supports the Read Byte protocol, as described in the System Management Bus specification.
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1 SCL 9 1 9
SDA START BY MASTER
0
1
0
1
1
A1
A0
R/W ACK. BY ADM1022
D7
D6
D5
D4
D3
D2
D1
D0 ACK. BY ADM1022
FRAME 1 SERIAL BUS ADDRESS BYTE 1 SCL (CONTINUED)
FRAME 2 ADDRESS POINTER REGISTER BYTE 9
SDA (CONTINUED)
D7
D6
D5
D4
D3
D2
D1
D0 ACK. BY STOP BY ADM1022 MASTER
FRAME 3 DATA BYTE
Figure 11a. Writing a Register Address to the Address Pointer Register, then Writing Data to the Selected Register
1 SCL 9 1 9
SDA START BY MASTER
0
1
0
1
1
A1
A0
R/W ACK. BY ADM1022
D7
D6
D5
D4
D3
D2
D1
D0 ACK. BY ADM1022 STOP BY MASTER
FRAME 1 SERIAL BUS ADDRESS BYTE
FRAME 2 ADDRESS POINTER REGISTER BYTE
Figure 11b. Writing to the Address Pointer Register Only
1 SCL 9 1 9
SDA START BY MASTER
0
1
0
1
1
A1
A0
R/W ACK. BY ADM1022
D7
D6
D5
D4
D3
D2
D1
D0 STOP BY NO ACK. BY MASTER MASTER
FRAME 1 SERIAL BUS ADDRESS BYTE
FRAME 2 DATA BYTE FROM ADM1022
Figure 11c. Reading Data from a Previously Selected Register
TEMPERATURE MEASUREMENT SYSTEM Internal Temperature Measurement
The ADM1022 contains an on-chip bandgap temperature sensor. The on-chip ADC performs conversions on the output of this sensor and outputs the temperature data in 8-bit twos complement format. The format of the temperature data is shown in Table II.
External Temperature Measurement
of VBE, varies from device to device, and individual calibration is required to null this out, so the technique is unsuitable for mass-production. The technique used in the ADM1022 is to measure the change in VBE when the device is operated at two different currents. This is given by: VBE = KT/q x ln(N) where: K is Boltzmann's constant q is charge on the carrier T is absolute temperature in Kelvins N is ratio of the two currents Figure 12 shows the input signal conditioning used to measure the output of an external temperature sensor. This figure shows the external sensor as a substrate transistor, provided for temperature monitoring on some microprocessors, but it could equally well be a discrete transistor.
The ADM1022 can measure the temperature of two external diode sensors or diode-connected transistors, connected to Pins 9 and 10 or 11 and 12. Pins 9 and 10 are a dedicated temperature input channel. The default function of Pins 11 and 12 is the THERM input/output and a general purpose logic input (GPI), but they can be configured to measure a diode sensor by setting Bit 7 of the Configuration Register to 1. The forward voltage of a diode or diode-connected transistor, operated at a constant current, exhibits a negative temperature coefficient of about -2 mV/C. Unfortunately, the absolute value
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VDD I N I IBIAS
LAYOUT CONSIDERATIONS
Digital boards can be electrically noisy environments, and care must be taken to protect the analog inputs from noise, particularly when measuring the very small voltages from a remote diode sensor. The following precautions should be taken:
VOUT+ TO ADC
D+ REMOTE SENSING TRANSISTOR
D-
BIAS DIODE
VOUT- LOW-PASS FILTER fC = 65kHz
1. Place the ADM1022 as close as possible to the remote sensing diode. Provided that the worst noise sources such as clock generators, data/address buses and CRTs are avoided, this distance can be four to eight inches. 2. Route the D+ and D- tracks close together, in parallel, with grounded guard tracks on each side. Provide a ground plane under the tracks if possible. 3. Use wide tracks to minimize inductance and reduce noise pickup. 10 mil track minimum width and spacing is recommended.
GND 10MIL 10MIL
Figure 12. Signal Conditioning
If a discrete transistor is used, the collector will not be grounded, and should be linked to the base. If a PNP transistor is used the base is connected to the D- input and the emitter to the D+ input. If an NPN transistor is used, the emitter is connected to the D- input and the base to the D+ input.
Table II. Temperature Data Format
D+
10MIL 10MIL
Temperature -128C -125C -100C -75C -50C -25C -1C 0C +1C +10C +25C +50C +75C +100C +125C +127C
Digital Output 1000 0000 1000 0011 1001 1100 1011 0101 1100 1110 1110 0111 1111 1111 0000 0000 0000 0001 0000 1010 0001 1001 0011 0010 0100 1011 0110 0100 0111 1101 0111 1111
D-
10MIL 10MIL
GND
10MIL
Figure 13. Arrangement of Signal Tracks
4. Try to minimize the number of copper/solder joints, which can cause thermocouple effects. Where copper/solder joints are used, make sure that they are in both the D+ and D- path and at the same temperature. Thermocouple effects should not be a major problem as 1C corresponds to about 200 V, and thermocouple voltages are about 3 V/oC of temperature difference. Unless there are two thermocouples with a big temperature differential between them, thermocouple voltages should be much less than 200 V. 5. Place 0.1 F bypass and 1000 pF input filter capacitors close to the ADM1022. 6. If the distance to the remote sensor is more than eight inches, the use of twisted pair cable is recommended. This will work up to about 6 to 12 feet. 7. For really long distances (up to 100 feet) use a shielded twisted pair such as Belden #8451 microphone cable. Connect the twisted pair to D+ and D- and the shield to GND close to the ADM1022. Leave the remote end of the shield unconnected to avoid ground loops. Because the measurement technique uses switched current sources, excessive cable and/or filter capacitance can affect the measurement. When using long cables, the filter capacitor C1 may be reduced or removed. In any case, the total shunt capacitance should not exceed 1000 pF. Cable resistance can also introduce errors. 1 series resistance introduces about 0.5C error.
To prevent ground noise interfering with the measurement, the more negative terminal of the sensor is not referenced to ground, but is biased above ground by an internal diode at the D- input. If the sensor is used in a very noisy environment, a capacitor of value up to 1000 pF may be placed between the D+ and D- inputs to filter the noise. To measure VBE, the sensor is switched between operating currents of I and N x I. The resulting waveform is passed through a 65 kHz low-pass filter to remove noise, thence to a chopperstabilized amplifier that performs the functions of amplification and rectification of the waveform to produce a dc voltage proportional to VBE. This voltage is measured by the ADC to give a temperature output in 8-bit twos complement format. To further reduce the effects of noise, digital filtering is performed by averaging the results of 16 measurement cycles. An external temperature measurement takes nominally 9.6 ms.
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ANALOG OUTPUT
12V
The ADM1022 has a single analog output (FAN_SPD) from an unsigned 8-bit DAC that produces 0 V-2.5 V. The analog output register defaults to 00 during power-on reset, which produces minimum fan speed. The analog output may be amplified and buffered with external circuitry such as an op amp and transistor to provide fan speed control. Suitable fan drive circuits are given in Figures 14a to 14e. When using any of these circuits, the following points should be noted: 1. All of these circuits will provide an output range from zero to almost +VFAN. 2. To amplify the 2.5 V range of the analog output up to +VFAN, the gain of these circuits needs to be set as shown. 3. Care must be taken when choosing the op amp to ensure that its input common-mode range and output voltage swing are suitable. 4. The op amp may be powered from the +V rail alone. If it is powered from +V then the input common-mode range should include ground to accommodate the minimum output voltage of the DAC, and the output voltage should swing below 0.6 V to ensure that the transistor can be turned fully off. 5. In all these circuits, the output transistor must have an ICMAX greater than the maximum fan current, and be capable of dissipating power due to the voltage dropped across it when the fan is not operating at full speed. 6. If the fan motor produces a large back ElectroMotive Force (EMF) when switched off, it may be necessary to add clamp diodes to protect the output transistors in the event that the output goes from full-scale to zero very quickly. 7. Pulling FAN_SPD/NTEST_IN high externally on power-up causes NAND Test Mode to be invoked on the ADM1022. Therefore, a 4.7 k pull-down resistor should be added externally to the FAN_SPD pin to prevent ADM1022 inadvertently entering the NAND Tree Test Mode. Figure 14c shows how the FAN_OFF signal may be used (with any of the control circuits) to gate the fan on and off independent of the value on the FAN_SPD/NTEST_IN pin.
5V
FAN_SPD AD8519
R4 1k
+
R2 39k R1 10k
R3 1k
Q1 BD136 2SA968
Figure 14b. 12 V Fan Circuit with Op Amp and PNP Transistor
12V
FAN_SPD AD8519
R3 100k
+
R2 39k R1 10k FAN_OFF
Q1 NDT452 P
3.3V R4 1k Q2 NDT3055L
Figure 14c. 12 V Fan Circuit with Op Amp and P-Channel MOSFET
12V
R3 100k
R4 100k Q3 NDT452 P
R2 3.9k FAN_SPD R5 5k Q1/Q2 MBT3904 DUAL R1 1k
FAN_SPD AD8541
Figure 14d. Discrete 12 V Fan Drive Circuit with P-Channel MOSFET, Single Supply
+
R2 15k R1 10k 5V FAN Q1 NDT452 P
12V
R5 100k
R4 100k Q3 BC556 2N3906 R2 3.9k
Q4 BD132 TIP32A
Figure 14a. 5 V Fan Circuit with Op Amp
FAN_SPD R6 5k Q1/Q2 MBT3904 DUAL R3 100
R1 1k
Figure 14e. Discrete 12 V Fan Drive Circuit with Bipolar Output Single Supply
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ADM1022
FAULT TOLERANT FAN CONTROL
The ADM1022 incorporates a fault tolerant fan control capability that is tied to operation of the THERM output. It can override the setting of the analog output and force it to maximum to give full fan speed in the event of a critical over-temperature problem, even if, for some reason, this has not been handled by the system software. There are four temperature set point registers that will activate the fault tolerant fan control. Two of these limits are programmable by the user and two are hardware (read-only) registers that will operate if the user does not program any limits. The fault tolerant fan control is activated if a limit is exceeded for three or more consecutive readings. These limits are separate from the normal high and low temperature limits for the INT output, which do not affect the fault tolerant fan control or THERM output. A hardware limit of 70C for the on-chip temperature sensor is programmed into the register at address 13h. For the remote sensors, a hardware limit of 100C is programmed in to the register at address 17h. These are the default limits and the analog output will be forced to full-scale if the on-chip sensor reads more than 70C or either of the remote sensors reads more than 100C. This makes the fault tolerant fan control fail-safe in that it will operate at these temperatures even if the user has programmed no other limits, or in the event of a software malfunction. The user may override these default limits by programming new limits into registers at address 14h for the on-chip sensor and 18h for the remote sensors. The default values in these registers are the same as for the read-only registers (70C and 100C), but they may be programmed with higher or lower values. Once registers 13h and 14h have been programmed, or if the default is acceptable, Bit 1 of the configuration register must be set to "1." This bit is a write-once bit that can only be written to "1" and it has two effects: 1. It makes the values in registers 13h and 14h the active limits, and disables read-only registers 17h and 18h. 2. It locks the data into registers 13h and 14h, so they cannot be changed until the lock bit is reset, which is when RST2 is asserted or a Power-On Reset occurs. Once the hardware override of the analog output is triggered, it will only return to normal operation after three consecutive measurements that are five degrees lower than each of the above limits. The analog output can also be forced to full-scale by pulling the THERM pin (Pin 11) low. Bit 6 of the Status Register is also set. Whenever FAN_SPD output is forced to full-scale, the FAN_OFF output is negated.
THE ADM1022 INTERRUPT SYSTEM
Operation of the INT output is illustrated in Figure 15. Assuming that the temperature starts off within the programmed limits and that temperature interrupt sources are not masked, INT will go low if the temperature measured by any of the internal or external sensors goes outside the programmed high or low temperature limit for that sensor. INT also goes low whenever THERM is low.
100 C 90 C 80 C 70 C 60 C 50 C 40 C INT ACPI CONTROL METHODS CLEAR EVENT *ACPI AND DEFAULT CONTROL METHODS ADJUST TEMPERATURE LIMIT VALUES * * LOW LIMIT TEMP * * * * HIGH LIMIT
Figure 15. Operation of INT Output
Once the interrupt has been cleared, it will not be reasserted even if the temperature remains outside the limit previously exceeded. However, INT will be reasserted if: a) the temperature goes outside the other limit for the sensor or b) the previously exceeded limit is reprogrammed and the temperature is then outside the new limit on the next conversion cycle or c) an interrupt is generated by another source.
INTERRUPT MASKING
Any of the bits in the Interrupt Status Register can be masked out by setting the corresponding mask bit in the Interrupt Mask Register. That interrupt source will then no longer generate an interrupt. However, the bits in the status register will be set as normal.
INTERRUPT CLEARING
Reading the Interrupt Status Register will output the contents of the Register, then clear it. It will remain cleared until the monitoring cycle updates it, so the next read operation should not be performed on the register until this has happened, or the result will be invalid. The INT output is cleared with the INT_Clear bit, which is Bit 2 of the Configuration Register, without affecting the contents of the Interrupt (INT) Status Registers.
INTERRUPT STATUS MIRROR REGISTER
The ADM1022 has two interrupt outputs, INT and THERM. These have different functions. INT responds to violations of software programmed temperature limits and its interrupt sources are maskable, as described in more detail later. THERM is intended as a "fail-safe" interrupt output that cannot be masked. Interrupts and status bits are only set if a limit is exceeded for at least three consecutive conversions.
Whenever a bit in the Interrupt Status Register is set, the corresponding bit is also set in the mirror register at address 4Ch. This register allows a second management system to access the status data without worrying about clearing the data. The data in this register is for reading only and has no effect on the interrupt output. The contents of this register are cleared when read. REV. 0
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ADM1022
THERM INPUT/OUTPUT
Pin 11 may be configured as an input for a second temperature sensor by setting Bit 7 of the Configuration Register, or it may be used as an interrupt output by clearing Bit 7 of the Configuration Register, which is its default condition. The Thermal Management Input/Output (THERM) is a logic input/opendrain output. It can also function as a logic input. If THERM is taken low by an external source, the analog output will be forced to FFh to switch a controlled fan to maximum speed and FAN_OFF will be negated.
THERM OPERATING MODE
temperature falls five degrees below the limit for three consecutive measurements. While THERM is low, the analog output will go to FFh to boost a controlled fan to full speed and FAN_OFF will be negated. When the Fault Tolerant Fan Control state is exited, the analog FAN_SPD output returns to its previously programmed value, which may have been changed during the time that the FAN_SPD output was forced to FFh.
INTERRUPT STRUCTURE
THERM responds only to the "hardware" temperature limits at addresses 13h, 14h, 17h and 18h, not to the software programmed limits. The function of these registers was described earlier with regard to fault tolerant fan speed control.
HARDWARE TRIP POINT 5 TEMP
The Interrupt Structure of the ADM1022 is shown in more detail in Figure 17. As each measurement value is obtained and stored in the appropriate value register, the value and the limits from the corresponding limit registers are fed to the high and low limit comparators. The result of each comparison (1 = out of limit, 0 = in limit) is routed to the corresponding bit input of the Interrupt Status Register via a data demultiplexer, and used to set that bit high or low as appropriate. The Interrupt Mask Register has bits corresponding to each of the Interrupt Status Register Bits. Setting an Interrupt Mask Bit high forces the corresponding Status Bit output low, while setting an Interrupt Mask Bit low allows the corresponding Status Bit to be asserted. After masking, the status bits are all OR'd together to produce the INT output, which will pull low if any unmasked status bit goes high, i.e., when any measured value goes out of limit. The INT output is enabled when Bit 1 of the Configuration Register (INT_Enable) is high, and Bit 2 (INT_Clear) is low. The THERM output cannot be cleared nor its interrupt sources masked.
THERM PROGRAMMED VALUE
ANALOG OUTPUT
FFH
FFH
EXT THERM INPUT
Figure 16. Operation of THERM Output
THERM will go low if the hardware temperature limit is exceeded for three consecutive measurements. It will remain low until the
GPI INT. TEMP HIGH LIMIT FROM VALUE VALUE AND LIMIT REGISTERS LOW LIMIT INTERRUPT MASK REGISTER HIGH AND LOW LIMIT COMPARATORS EXT. TEMP2 1 = OUT OF DATA LIMIT DEMULTIPLEXER DIODE 2 FAULT RESERVED GPI EXT. TEMP1 THERM DIODE 1 FAULT 0 1 2 INTERRUPT 3 STATUS 4 REGISTER 5 6 7 MASK GATING STATUS BIT MASK BIT 8 INT
MASKING DATA FROM BUS 8 MASK BITS (SAME BIT ORDER AS STATUS REGISTER)
INT_ENABLE
INT_CLEAR
CONFIGURATION REGISTER
THIS CONNECTION ONLY RELEVANT IF THERM IS PULLED LOW EXTERNALLY. D2-/THERM
Figure 17. Interrupt Register Structure
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ADM1022
GENERAL PURPOSE LOGIC INPUT (GPI)
Pin 12 may be configured as an input for a second temperature sensor input by setting Bit 7 of the Configuration Register, or it may be used as a general purpose logic input by clearing Bit 7 of the Configuration Register, which is its default condition. The GPI input may be programmed to be active high or active low by clearing or setting Bit 6 of the Configuration Register. The default value is active high. Bit 4 of the Interrupt Status Register follows the state (or inverted state) of GPI and will generate an interrupt when it is set to one, like any other input to the Interrupt Status Register. However, the GPI bit is not latched in the Status Register and always reflects the current state (or inverted state) of the GPI input. If it is one it will not be cleared by reading the Status Register.
RESETS
Operation of the reset outputs at power-up, and for a manual reset input, is shown in Figure 18. It should be noted that the resets will only be asserted once VCC rises above 1 V. Below this voltage there is insufficient gate drive voltage to turn on the output FETs. If the device being reset and its pull-up resistor is supplied from VCC, the reset voltage will rise with VCC to 1 V before being pulled low. If the device being reset and its pull-up resistor use a separate supply voltage, the reset output will follow that voltage until reset is asserted. The ADM1022 can also be reset by taking RST1 low as an input. The above-mentioned registers will be reset to their default values and the ADC will remain inactive as long as RST1 is below the reset threshold.
VCC -1V
The ADM1022 has a manual reset input, (Pin 2 - MR), a bidirectional reset pin, (Pin 3 - RST1) and a reset output (Pin 7 - RST2). These operate as follows: Taking MR low forces a system reset and takes the RST2 output low. It will remain low for tRP after MR goes high again. The MR input has a 20 k pull-up resistor, and may be left unconnected if not used. MR is typically used to generate a system reset from a front-panel push-button. The RST1 pin is a bidirectional I/O. It is asserted low as an output if VCC falls below the reset threshold. It can also operate as a reset input to the ADM1022 in the same way as MR. At powerup, RST2 will remain asserted for tRP after RST1 goes high. The RST2 output is asserted low under any of the following conditions: the MR input is low, as previously described, - RST1 is asserted low as an output or pulled low as an input, VMON is below the reset threshold.
POWER-ON RESET
RST1
RST2
tRP
tRP
POWER-ON RESET
MR
RST2
t
tRP
MANUAL RESET (FOR EXAMPLE)
Figure 18. Operation of Reset Outputs
RST1 AS I/O
When the ADM1022 is powered up, it will initiate a power-on reset sequence when the supply voltage VCC rises above the power-on reset threshold, with registers being reset to their power-on values. Normal operation will begin when the supply voltage rises above the reset threshold. Registers whose poweron values are not shown have power on conditions that are indeterminate (this includes the Value and Limit Registers). In most applications, usually the first action after power-on would be to write limits into the Limit Registers. Power-on reset clears or initializes the following registers (the initialized values are shown in Table IV): - - - - - - - Configuration Register Interrupt Status Register Interrupt Status Mirror Register Interrupt Mask Register Test Register Analog Output Register Programmable Trip Point Registers
If RST1 is used as a reset input to the ADM1022 while also being used as a system reset output, it will be necessary to separate the two functions so that a reset from the system to the ADM1022 does not also reset the system. This can be achieved using the circuit of Figure 19. If ALT_RST is high, then reset outputs from the ADM1022 can pass through N2 to reset the system. If, however, ALT_RST is low, the ADM1022 will be reset, but SYS_RST will be held high by the high input from N1 to N2.
VCC
ADM1022
100k RST1
ALT_RST
N1
N2
SYS_RST
Figure 19. Separation of RST1 Input from RST1 Output
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REV. 0
ADM1022
5 V OPERATION
The ADM1022 may be operated with VCC and/or VMON connected to any supply voltage between 3.0 V and 5.5 V, but it should be noted that the reset threshold voltages are fixed and optimized for 3.3 V operation. If the VCC supply voltage is 5 V, for example, the VMON input can still be used to monitor another 3.3 V supply without problems. However, the reset threshold for the 5 V, VCC supply, may be below that at which 5 V logic will operate reliably and may not give a reliable indication of brownout on the 5 V supply. Alternatively, VMON may be configured to monitor a supply voltage higher than 3.3 V by adding an input attenuator. The ratio of R1 to R2 is given by: R1/R2 = (VR - 2.93)/2.93 Where VR is the desired reset voltage and 2.93 V is the nominal reset voltage of the VMON input.
The structure of the NAND Tree is shown in Figure 21. To perform a NAND Tree test, all pins are initially driven low. The test vectors set all inputs low, then one-by-one toggles them high (keeping them high). Exercising the test circuit with this "walking one" pattern, starting with the input closest to the output of the tree, cycling towards the farthest, causes the output of the tree to toggle with each input change. Allow for a typical propagation delay of 500 ns.
POWER-ON RESET CLK FAN_SPD/ NTEST_IN D LATCH Q ENABLE GPI SCL SDA MR ADD/NTEST_OUT
VIN
R1
VMON
Figure 21. NAND Tree
Table III. Test Vectors
R2
GPI
Figure 20. Scaling VMON to a Higher Reset Voltage
SCL 0 0 0 1 1
SDA 0 0 1 1 1
MR 0 1 1 1 1
ADD/NTEST_OUT 1 0 1 0 1
The input resistance of the VMON input is approximately 100 k, with a tolerance of around 30%, so the parallel combination of R1 and R2 should be much lower than 100 k to minimize errors due to variations in this input resistance.
INITIALIZATION (SOFT RESET)
0 0 0 0 1
CONFIGURING THE INTERRUPT
Soft reset performs a similar, but not identical, function to power-on reset. The Test Register and Analog Output register are not initialized. Soft reset is accomplished by setting Bit 4 of the Configuration Register high. This bit automatically clears after being set.
NAND TREE TEST
On power-up, the Interrupt functionality of the device is disabled. The Configuration Register (0x40) must be written to, in order to enable the Interrupt output. The INT_Clear bit (Bit 2) should be cleared to 0 and the INT_Enable bit (Bit 1) of the Register should be set to 1. If the INT_Enable bit is set, and the INT_Clear bit is not cleared to 0, then any interrupts generated will be reflected in the Interrupt Status Register, but will not toggle the Interrupt pin externally.
A NAND tree is provided in the ADM1022 for Automated Test Equipment (ATE) board level connectivity testing. The device is placed into NAND tree test mode by powering up with pin FAN_SPD/NTEST_IN (Pin 8) held high. This pin is sampled and its state at power-up is latched. If it is connected high, the NAND tree test mode is invoked. NAND tree test mode will only be exited once the ADM1022 is powered down. In NAND tree test mode, all digital inputs may be tested as illustrated in Table III. ADD/NTEST_OUT will become the NAND tree output pin.
REV. 0
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ADM1022
Table IV. Registers
Register Name Value Registers Company ID Revision
Address A7-A0 in Hex 0x13-0x3A 0x3E 0x3F
Comments See Table V. This location will contain the company identification number. This register is read only. This location will contain the revision number of the part in the lower four bits of the register [3:0]. The upper four bits reflect the ADM1022 Version Number [7:4]. The first version is 1100. The next version of ADM1022 would be 1101, etc. For instance, if the stepping were A0 and this part is an ADM1022, this register would read 1100 0000. This register is read only. See Table VI. Power-On Value = 0010 0101. See Table VII. Power-On Value = 0000 0000. See Table VIII. Power-On Value = 0000 0000.
Configuration Register Interrupt Status Register Reserved for Future Use Interrupt Mask Register Reserved for Future Use Reserved for Future Use Reserved for Future Use Interrupt Status Register Mirror
0x40 0x41 0x42 0x43 0x44 0x47 0x4A 0x4C
See Table IX. Power-On Value = 0000 0000.
Table V. Registers 0x13-0x3A Value Registers
Address 0x13 0x14
Read/Write Read/Write Read/Write
Description Programmable Local Temp Sensor Automatic Trip Point--Default 70C. This register can only be written to if the write once bit in the configuration register (0x40, Bit 3) has not been set. Programmable Remote Thermal Diode Automatic Trip Point--Default 100C. This register can only be written to if the write once bit in the configuration register (0x40, Bit 3) has not been set. Test Register for manufacturer's use only. Do not write to this register. Default Local Temp Sensor Automatic Trip Point--Default 70C. Cannot be changed. Disabled when Bit 3 of Configuration Register is set. Default Remote Thermal Diode Automatic Trip Point--Default 100C. Cannot be changed. Disabled when Bit 3 of Configuration Register is set. Analog Output, FAN_SPD (Defaults to 0x00h). External Temperature Value Diode 2. External Temperature Value Diode 1. Internal Temperature. External Temperature Diode 2 High Limit. External Temperature Diode 2 Low Limit. External Temperature Diode 1 High Limit. External Temperature Diode 1 Low Limit. Internal Temperature High Limit. Internal Temperature Low Limit.
0x15 0x17 0x18 0x19 0x20 0x26 0x27 0x2B 0x2C 0x37 0x38 0x39 0x3A
Read/Write Read Only Read Only Read/Write Read Only Read Only Read Only Read/Write Read/Write Read/Write Read/Write Read/Write Read/Write
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ADM1022
Table VI. Register 0x40 Configuration Register
Bit 0
Name START
Read/Write Read/Write
Description Setting this bit to a "1" enables startup of ADM1022; clearing this bit to a "0" places ADM1022 in standby mode. Caution: The INT output will not be cleared if the user clears this bit after an interrupt has occurred (see "INT Clear" bit). At startup temperature monitoring and limit checking functions begin. Note, all limit values should be programmed into ADM1022 prior to using the standard thermal interrupt mechanism based upon high and low limits. (Power-Up Default = 1.) Setting this bit to a "1" enables the INT output. 1 = Enabled 0 = Disabled (Power-Up Default = 0). This bit clears the INT output when set (1) without affecting the contents of the Interrupt Status Register. (Power-Up Default = 1.) Setting this bit to a "1" will lock in the value set into the Programmable Local and Remote Automatic Trip Point Registers (Value Register locations 0x13 and 0x14). Furthermore, when this bit is set, the values in the Default Local and Remote Automatic Trip Point Registers (Value Register locations 0x17 and 0x18) will no longer have an effect on the THERM, FAN_SPD or FAN-OFF outputs. This bit cannot be written again until after RST2 has been asserted or Power-On Reset occurs. (Power-Up Default = 0.) Setting this bit to a "1" will restore power-up default values to the Configuration Register, Interrupt Status Register, Interrupt Status Register Mirror, Interrupt Mask Register. This bit automatically clears itself since the power-on default is zero. Setting this bit to a "1" will cause the FAN OFF pin to be floated. Clearing this bit to "0" will cause the FAN OFF pin to be driven low, which requests that the fan be turned off. This bit will be unconditionally set if the THERM pin is ever asserted. Reading this bit reflects the state of the FAN-OFF output buffer. Due to the open-drain nature of this pin the value read does not represent the actual state of the external circuit connected to it. (Power-Up Default = 1.) Setting this bit to a "1" will invert the GPI input for the purpose of level detection and interrupt generation. Clearing this bit to a "0" leaves the GPI input unmodified. (PowerUp Default = 0.) Setting this bit configures Pins 11 and 12 as inputs for a second diode temperature sensor. Clearing this bit configures Pin 11 as THERM output and Pin 12 as general purpose logic input (GPI). (Power-Up Default = 0.)
1 2 3
INT Enable INT Clear Programmable Automatic Trip Point Lock Bit
Read/Write Read/Write Read/Write Once
4
Soft Reset FAN OFF
Read/Write
5
Read/Write
6
GPI Invert
Read/Write
7
D2
Read/Write
Table VII. Register 0x41 Interrupt Status Register. Power-On Default <7:0> = 00h
Bit 0 1 2 3 4
Name Int. Temp Error Ext. Temp2 Error Diode 2 Fault Reserved GPI Input
Read/Write Read Only Read Only Read Only Read Only Read Only
Description A one indicates that one of the internal temperature sensor limits has been exceeded. A one indicates that one of the limits for the second external temperature sensor has been exceeded. A one indicates either a short- or open-circuit fault on remote sensor diode 2. Undefined. A "1" indicates that the GPI pin is asserted. The polarity of the GPI pin is determined by GPI Invert (Bit 6) in the Configuration Register. For example, if GPI Invert is cleared, this bit will be "1" when the GPI pin is high ("1"); this bit will be "0" when the GPI pin is low ("0"). If GPI Invert is set, this bit will be "1" when the GPI pin is low ("0"); this bit will be "0" when the GPI pin is high ("1"). Note that the state of GPI is not latched; this bit simply reflects the state or inverted state of the GPI pin. Note: if this bit is "1" reading this register will NOT clear it to "0." A one indicates that one of the limits for the first external temperature sensor has been exceeded. A one indicates that the thermal overload (THERM) line has been asserted externally. A one indicates either a short- or open-circuit fault on remote sensor diode 1.
5 6 7
Ext. Temp1 Error THERM Input Diode 1 Fault
Read Only Read Only Read Only
NOTE: An error that causes continuous interrupts to be generated may be masked in its respective mask register until the error can be alleviated.
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ADM1022
Table VIII. 0x43 Interrupt Mask Register. Power-On Default <7:0> = 00h
Bit 0 1 2 3 4 5 6 7
Name Int. Temp Error Ext. Temp2 Error Diode 2 Fault Reserved GPI Input Ext. Temp1 Error THERM Input Diode 1 Fault
Read/Write Read Only Read Only Read Only Read Only Read/Write Read/Write Read/Write Read/Write
Description A one disables the corresponding interrupt status bit for the INT output. A one disables the corresponding interrupt status bit for the INT output. A one disables the corresponding interrupt status bit for the INT output. Undefined. A one disables the corresponding interrupt status bit for the INT output. A one disables the corresponding interrupt status bit for the INT output. A one disables the corresponding interrupt status bit for the INT output. A one disables the corresponding interrupt status bit for the INT output.
Table IX. Register 0x4C Interrupt Status Register Mirror. Power-On Default <7:0> = 00h
Bit 0 1 2 3 4
Name Int. Temp Error Ext. Temp2 Error Diode 2 Fault Reserved GPI Input
Read/Write Read Only Read Only Read Only Read Only Read Only
Description A one indicates that one of the internal temperature sensor limits has been exceeded. A one indicates that one of the limits for the second external temperature sensor has been exceeded. A one indicates either a short- or open-circuit fault on remote sensor diode 2. Undefined A "1" indicates that the GPI pin is asserted. The polarity of the GPI pin is determined by GPI Invert (Bit 6) in the Configuration Register. For example, if GPI Invert is cleared, this bit will be "1" when the GPI pin is high ("1"); this bit will be "0" when the GPI pin is low ("0.") If GPI Invert is set, this bit will be "1" when the GPI pin is low ("0"); this bit will be "0" when the GPI pin is high ("1"). Note that the state of GPI is not latched; this bit simply reflects the state or inverted state of the GPI pin. Note: if this bit is "1" reading this register will NOT clear it to "0." A one indicates that one of the limits for the first external temperature sensor has been exceeded. A one indicates that the thermal overload (THERM) line has been asserted externally. A one indicates either a short- or open-circuit fault on remote sensor diode 1.
5 6 7
Ext. Temp1 Error THERM Input Diode 1 Fault
Read Only Read Only Read Only
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ADM1022
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
16-Lead QSOP (RQ-16)
0.197 (5.00) 0.189 (4.80)
16
9
0.157 (3.99) 0.150 (3.81)
1 8
0.244 (6.20) 0.228 (5.79)
PIN 1 0.059 (1.50) MAX
0.069 (1.75) 0.053 (1.35)
0.010 (0.25) 0.004 (0.10)
0.025 (0.64) BSC
8 0 0.012 (0.30) SEATING 0.010 (0.20) 0.008 (0.20) PLANE 0.007 (0.18)
0.050 (1.27) 0.016 (0.41)
REF: JEDEC 0.150" SSOP - DRAWING NUMBER MO-137
REV. 0
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PRINTED IN U.S.A.
C3617-2.5-4/00 (rev. 0) 00057

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