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| Order this document by MC13173/D Infrared Integrated Transceiver IC The MC13173 is a low power infrared integrated system (IRIS). It is a unique blend of a split IF wideband FM receiver and a specialized infrared LED transmitter. This device was designed to provide communications between portable computers via a half duplex infrared link at data rates up to 200 kbps. The receiver includes a mixer, IF amplifier and limiter and data slicer. The IF amplifier is split to accommodate two low cost cascaded filters. The RSSI output is derived by summing the output of both IF sections. The transmitter section includes a frequency synthesizer, FSK modulator, harmonic low pass filter and an IR LED driver. * Transmitter Operates in Two Modes: - On/Off Pulsing for Remote Control - FSK Modulation at 1.4 MHz for Data Communications * Over 70 dB of RSSI Range MC13173 INFRARED TRANSCEIVER SEMICONDUCTOR TECHNICAL DATA 32 1 * * * Split IF for Improved Filtering and Extended RSSI Range Digitally controlled Via a Six Line Interface Bus Individual Circuit Blocks Can Be Powered Down When Not In Use for Power Conservation Device MC13173FTB FTB SUFFIX PLASTIC PACKAGE CASE 873 (Thin QFP) ORDERING INFORMATION Operating Temperature Range TA = - 40 to +85C Package TQFP-32 Simplified Block Diagram 32 kHz Ref 32 12 M 1 Ma PLL 31 Tx PLL 30 14 MHz Ref 29 T 28 Data In 27 E 26 IR LED Driver 25 24 LED Driver Feedback V EE3 Data Out VEE2 Data Slicer In Demod Quad Coil Carrier Detect Master VCO/PLL FSK Modulator Mode Select Harmonic LPF Driver V EE1 2 R RF In1 3 23 22 Data Slicer 4 Mixer 5 21 20 RF In2 Mixer Out VReg1 6 IF Amplifier Limiter VReg2 19 18 17 9 IF Dec1 10 IF Dec2 11 IF Out 12 VCC2 13 Lim In 14 Lim Dec1 15 Lim Dec2 16 RSSI VCC1 7 IF In 8 This device contains 914 active transistors. (c) Motorola, Inc. 1996 Rev 0 MOTOROLA ANALOG IC DEVICE DATA 1 MC13173 MAXIMUM RATINGS Rating Power Supply Voltage Junction Temperature Storage Temperature Symbol VCC - VEE TJ Tstg Value 6.0 150 - 55 to +150 Unit Vdc C C NOTE: Devices should not be operated at or outside these values. The "Recommended Operating Conditions" table provides for actual device operation. RECOMMENDED OPERATING CONDITIONS Characteristic Power Supply Voltage Ambient Temperature Range Symbol VCC - VEE TA Value 2.7 to 5.5 - 40 to +85 Unit Vdc C DC ELECTRICAL CHARACTERISTICS (TA = +25C, VCC = 3.3 Vdc, fREF = 32.768 kHz. Measured using test circuit in Figure 1, unless otherwise noted.) Characteristic Supply Current (See Table 2) Control Pin Logic State T 0 1 1 0 R 1 0 0 0 E 0 0 1 0 31 IMA Pin 7, 12 Symbol ICC Min Typ Max Unit Receive Mode Communications Mode A/V Mode Standby Mode Master PLL Charge Current DATA SLICER Data Slicer Threshold Voltage Maximum Pull-Down Current CARRIER DETECT Carrier Detect Threshold Voltage Maximum Pull-Down Current TRANSMITTER Maximum Pull-Up Current Maximum Pull-Down Current DC Output Voltage Transmit PLL Charge Current - - - - - 6.5 4.75 1.5 <10 25 9.0 8.0 - - - mA nA A 20 22 VTH1 IDS VTH2 ICD 0.85 1.0 1.1 1.8 1.4 - Vdc mA 16 17 1.0 1.1 1.15 3.0 1.3 - Vdc mA 25 25 24 30 IOH IOL VO ITX 5.8 - - - 7.0 150 200 25 - 700 - - mA A mV A AC ELECTRICAL CHARACTERISTICS (TA = +25C, VCC = 3.3 Vdc, fREF = 32.768 kHz. Measured using test circuit in Figure 1, unless otherwise noted.) Characteristic TRANSMITTER Upper Sideband Frequency (Mark) Lower Sideband Frequency (Space) Upper and Lower Sideband Amplitude RECEIVER Receiver Sensitivity - 12 dB SINAD MIXER Mixer Conversion Gain Mixer Output Impedance 4, 5, 6 6 AV(Mix) ZO - - 23.5 330 - - dB 4, 19 VSIN - 5.0 - V 24 24 24 fHI fLO VSB - - 40 1.427 1.317 54 - - 70 MHz MHz mVrms Pin Symbol Min Typ Max Unit 2 MOTOROLA ANALOG IC DEVICE DATA MC13173 AC ELECTRICAL CHARACTERISTICS (continued) (TA = +25C, VCC = 3.3 Vdc, fREF = 32.768 kHz. Measured using test circuit in Figure 1, unless otherwise noted.) Characteristic IF AMPLIFIER IF Amplifier Gain IF Amplifier RSSI Slope Input Impedance Output Impedance RSSI Current Range RSSI Dynamic Range LIMITING AMPLIFIER Input Impedance Limiter RSSI Slope RSSI Current Range RSSI Dynamic Range 13 16 16 16 ZIN - - - - - - - 330 360 20 58 - - - - nA/dB A dB 8, 11 16 8 11 16 16 - - ZIN ZO - - - - - - - - 54 275 330 330 20 70 - - - - - - dB nA/dB A dB Pin Symbol Min Typ Max Unit Figure 1. Test Circuit MC33202 10 k 127 k 0.1 F 0.001 F 100 k 100 k VEE 100 nF VCC VCC - 1V 10 k 10 nF VCC 0.3 H MV209 VCC - 1V 200 k 100 k 100 k 10 k VCC VCC 0.001 F MV209 VCC 32 0.001 F VCC VCC 10 k 10 k 200 LPF ATTEN VCC F1 VCC 8 330 V CC 50 0.1 F 100 n 1.0 n 1.0 n VCC 330 VCC 9 VCC 0.1 F 0.1 F 100 n 1.0 n VCC 1.0 n 16 17 0.1 H 1 25 24 100 n VEE VCC + V 33 F EE MC13173 10 k 6.81 k VEE 150 p 1.0 H VCC 0.1 F VEE 100 n VCC 0.1 F 100 2N2222A 10 k VCC 0.1 H VCC 50 0.1 F VCC VCC 10 p VCC 100 p 100 p VCC 10 k VCC VCC 100 p 36 k 24.9 k 20 p 100 pF V CC 50 VCC MOTOROLA ANALOG IC DEVICE DATA 3 MC13173 CIRCUIT DESCRIPTION General The MC13173 infrared transceiver integrates a split IF wideband FM receiver and an IR LED transmitter into a single IC. The transmitter is comprised of an FSK modulator, harmonic low pass filter, and IR LED driver. The receiver consists of a mixer, IF amplifier and limiting IF, detector, and data slicer. It includes RSSI and carrier detect functions. The transmitter is capable of two modes of operation. It was primarily designed for use in the Communications Mode, which enables point-to-point data links, such as the communication from keyboard to computer, or for the exchange of data between portable computers. In this mode it is capable of 200 kbps half duplex FSK operation. The transmitter can also operate in an "A/V" Mode, which pulses the LED on and off with no carrier. (See Figure 11). Digital Interface Bus The MC13173 is controlled via a six line 3.3 V digital interface bus. That includes three control pins, data in and out pins, and a carrier detect pin. Listed below is a brief description of each pin and its function. Table 1. Digital Interface Pin Descriptions Pin 28 27 3 22 17 26 Pin Name Transmit Enable Data In Receive Enable Data Out Carrier Detect Transmit Modulation Enable Symbol T DI R DO CD E I/O I I I O O I Description High - Transmitter is enabled Low - Transmitter is disabled Data Input - 38.2 kbps Communication Mode High - Receiver is enabled Low - Receiver is disabled Demodulated Output Signal High - Carrier is present Low - Carrier is not present High - Transmitter is in A/V Mode Low - Transmitter is in Communications Mode This transceiver was designed for use in battery powered, hand-held consumer products. To minimize power consumption, the digital interface enables individual system blocks to be powered down while not in use. The following diagram shows the mode of the IC and the power state of each circuit block for a given set of control levels. Table 2. Power State Table Control Pins* T 0 0 0 1 1 1 1 R 0 0 1 1 1 0 0 E 0 1 X 1 0 0 1 OFF OFF Receive Receive Transmit - Comm Mode Transmit - Comm Mode Transmit - A/V Mode Md Mode Master VCO Off Off On On On On Off Circuit Block Power States (See Figures 2 and 3) FSK Modulator Off Off Off Off On On Off Receiver Off Off On On On Off Off LED Driver Off Off Off On On On On Supply Current (Typical) 10 nA 70 A 6.5 mA 7.5 mA 9.0 mA 4.75 mA 1.5 mA * With Data In Pin Low 4 MOTOROLA ANALOG IC DEVICE DATA MC13173 Master VCO/PLL The master VCO provides the reference frequency for the FSK modulator and the LO frequency for the receiver downconverter. With a 32.768 kHz input frequency to the master VCO on Pin 1, the LO frequency for the receiver will be at 12.075 MHz. The reference frequency for the FSK modulator will be at approximately 1.1 MHz. The master VCO and FSK modulator are not used when the transmitter is used in A/V mode, and both are powered down. Receiver Description The single conversion receiver portion of the MC13173 is low power and wideband, and incorporates a split IF. This section includes a mixer, IF amplifier, limiting IF, quadrature detector and data slicer. Mixer The mixer is a double balanced four quadrant multiplier. It can be driven either differentially or single-ended by connecting the unused input to the positive supply rail. The buffered output is internally loaded for an output impedance of 330 for use with a standard ceramic filter. IF Amplifier The first IF amplifier section is composed of three differential stages with the second and third stages contributing to the RSSI. This section has internal DC feedback and external input decoupling for improved symmetry and stability. The total gain of the IF amplifier block is approximately 40 dB. The fixed internal input impedance is 330 for use with a 10.7 MHz ceramic filter. The output of the IF amplifier is buffered and the impedance is 330 . Limiter The limiter section is similar to the IF amplifier section, except that four stages are used with the last three contributing to the RSSI. This IF limiting amplifier section drives the quadrature detector internally. RSSI/Carrier Detect The received signal strength indicator (RSSI) outputs a current proportional to the log of the received signal amplitude. The RSSI current output is derived by summing the currents from the IF and limiting amplifier stages. An external resistor sets the output voltage range. The carrier detect threshold is set at approximately 1.2 Vdc. When the RSSI level exceeds that threshold, the carrier detect output will go high. A large resistor may be added externally between the comparator output and the positive input for hysteresis. Quadrature Detector The demodulator is a conventional quadrature type with an external LC tank driven through an internal 5 pF capacitor. The output is buffered to give an output impedance of less than 1.0 k at an average DC level of around 1.1 V. Data Slicer The data slicer is designed to square up the data signal. It is self centering at about 1.1 V, and clips at about 0.75 V and 1.45 V. There is a short time constant for large peak-to-peak voltage swings or when there is a change in DC level at the detector output. The time constant is longer for small signals or for continuous bits of the same polarity which drift close to the threshold voltage. Transmission Description The MC13173 uses a dual modulus PLL to frequency shift key (FSK) modulate the baseband digital input signal, producing the necessary logic high and low frequencies for transmission. The transmit frequency for a logic high is 1.427 MHz, and the frequency for a low is 1.317 MHz with a 32.768 kHz reference frequency. FSK Modulator In the communications mode, the FSK modulator uses the reference frequency from the Master VCO to produce the two frequencies required for a logic high and a logic low. In the A/V mode, the FSK modulator is not used and is powered down. LED Driver Stage A low pass filter following the FSK modulator removes the undesired harmonic frequencies from the square-wave output of the divider circuits in PLLs. The resulting sinusoidal waveforms are fed into a unity gain difference amplifier, which drives the base of an external transistor, modulating the IR LED. In A/V mode, the data is input directly into the inverting input of the op amp, and the low pass filter is not used. MOTOROLA ANALOG IC DEVICE DATA 5 MC13173 DOCUMENT CONTAINS SCANNED IMAGES WHICH COULD NOT BE PROCESSED FOR PDF FILES. FOR COMPLETE DOCUMENT WITH IMAGES PLEASE ORDER FROM MFAX OR THE LITERATURE DISTRIBUTION CENTER 6 MOTOROLA ANALOG IC DEVICE DATA MC13173 Figure 2. Transmitter Block Diagram VCC fR PFD/ Charge Pump PFD/ Charge Pump VCC /2 LED Driver Stage Harmonic LPF /10 LED Driver fM1 fM2 FSK Modulator Master VCO /67 fLO /11 /12 /13 VCC Data In (Comm Mode) Data In (A/V Mode) fR = 32.768 kHz fLO = 67 X 11 fR 2 Data High: fM1 = 13 f 11 X 10 LO 12 Data Low: fM2 = f 11 X 10 LO Figure 3. Receiver Block Diagram fR /2 PFD/ Charge Pump Master VCO fLO Receiver /11 /67 VReg1 Carrier Detect VCC Mixer RF Input IF Amplifier Limiter VReg2 Detector RSSI Data Output VCC MOTOROLA ANALOG IC DEVICE DATA 7 MC13173 Table 3. PIN FUNCTION DESCRIPTION (TA = 25C, VCC = 5.0 Vdc, fREF = 32.768 kHz, fMOD = 32.768 kHz) Pin 1 Symbol 12 M Description VCO for Master PLL. (Measured using a low capacitance FET probe. Standard oscilloscope probes can pull oscillator off frequency. See Figure 14.) Internal Equivalent Circuit VCC Waveform 1 VEE 2, 21, 23 3 4, 5 VEE DC ground. Should be connected to a continuous ground plane on the PCB. Receive Enable Pin. See Tables 1 & 2. RF Input to the mixer. 1.375 MHz average carrier frequency with 50 kHz deviation. 4 5 VCC R RF In1 RF In2 VEE 6 Mixer Out 10.7 MHz IF ZO = 330 RF In = - 20 dBm Modulation = 32.768 kHz 6 VCC VEE 7, 12 8 VCC Supply voltage and RF ground, should be decoupled to VEE. IF input impedance is 330 . RF In = - 20 dBm Modulation = 32.768 kHz 10 8 9 VCC IF In VEE 8 MOTOROLA ANALOG IC DEVICE DATA MC13173 Table 3. PIN FUNCTION DESCRIPTION (continued) (TA = 25C, VCC = 5.0 Vdc, fREF = 32.768 kHz, fMOD = 32.768 kHz) Pin 9, 10 11 Symbol IF Dec IF Out Description IF decoupling as shown in Figure 15. IF Output. ZO = 330 . -20 dBm RF input level. Output is sinusoidal with lower drive levels. Internal Equivalent Circuit See Circuit for Pin 8. Waveform VCC 11 VEE 13 Lim In Limiter input. ZIn = 330 . 15 13 14, 15 Lim Dec External limiter decoupling as shown in application circuit. 14 VCC VEE 16 RSSI Received Signal Strength Indicator Output. (See Figure 13) Logic output of the carrier detect comparator. VEE 18 Quad Coil Quadrature tuning circuit. Modulated 10.7 MHz IF. Measured with a low capacitance FET probe. 5p 18 VCC 17 17 Carrier Detect VEE 19 Demod Demodulated signal output measured at the pin (before filtering). Modulation = 32.768 kHz sine wave. VCC 19 VEE MOTOROLA ANALOG IC DEVICE DATA 9 MC13173 Table 3. PIN FUNCTION DESCRIPTION (continued) (TA = 25C, VCC = 5.0 Vdc, fREF = 32.768 kHz, fMOD = 32.768 kHz) Pin 20 Symbol Data Slicer In Data Out Description Input from the receiver demodulated output. Output from the receiver data slicer. Modulation = 32.768 kHz sine wave. RF input driven by frequency generator. See also Figure 10. Internal Equivalent Circuit Waveform 22 24 LED Driver Feedback IR LED Driver Feedback for the LED driver op amp. 25 Output of the unity gain output buffer in Communications Mode. See Figure 11 for transmit output in A/V mode. Modulation = 32.768 kHz square wave. . VCC 24 25 25 k VEE 26 E Transmit Modulation Enable. See Tables 1 & 2. Modulation input for transmit data. Transmit Enable pin. See Tables 1 & 2. VCO for FSK Modulator phase locked loop. (Measured using a low capacitance FET probe. Standard oscilloscope probes can pull oscillator off frequency. See Figure 14.) No modulation (Data In low). VEE VCC 27 28 29 Data In T 14 MHz Ref 29 10 MOTOROLA ANALOG IC DEVICE DATA MC13173 Table 3. PIN FUNCTION DESCRIPTION (continued) (TA = 25C, VCC = 5.0 Vdc, fREF = 32.768 kHz, fMOD = 32.768 kHz) Pin 30 Symbol Tx PLL Description Phase detector output for the FSK Modulator. (With loop closed and locked.) No modulation (Data In low). VCC Internal Equivalent Circuit Waveform 30 With 32.768 kHz square wave modulation. Note: Probing the output of the phase detectors directly may disturb the loop. It is best to probe the output of the op amp when evaluating loop response. VEE 31 Ma PLL Output of the phase detector charge pump for the Master PLL. (With loop closed and locked.) VCC 31 VEE 32 32 kHz Ref Input to 32.768 kHz reference. Filtered from TTL oscillator using application circuit in Figure 15. Approximately 1.0 Vp-p triangle wave at 32.768 kHz. 32 VCC VEE MOTOROLA ANALOG IC DEVICE DATA 11 MC13173 Typical Performance Over Temperature (Measured using test circuit in Figure 1) Figure 4. Normalized Mixer Gain versus Temperature 1.0 NORMALIZED IF AMP GAIN NORMALIZED MIXER GAIN 1.0 Figure 5. Normalized IF Amp Gain versus Temperature 0.5 0.5 0 0 -0.5 -0.5 -1.0 - 50 0 50 100 -1.0 - 50 0 50 100 TA, AMBIENT TEMPERATURE (C) TA, AMBIENT TEMPERATURE (C) IO , MAXIMUM PULL-UP CURRENT (mA) 7.0 IO , MAXIMUM PULL-DOWN CURRENT ( A) Figure 6. Maximum Pull-Up Current versus Temperature (Pin 25) Figure 7. Maximum Pull-Down Current versus Temperature (Pin 25) 140 130 120 110 100 90 80 70 60 - 50 0 50 100 6.5 6.0 5.5 - 50 0 50 100 TA, AMBIENT TEMPERATURE (C) TA, AMBIENT TEMPERATURE (C) Figure 8. Supply Current versus Temperature - 4.5 - 5.0 Transmit Communications Mode - 5.5 - 6.0 Receive Mode - 6.5 -7.0 - 50 VTH, THRESHOLD VOLTAGE (V) ICC , SUPPLY CURRENT (mA) 1.5 Figure 9. Data Slicer and Carrier Detect Threshold Voltages versus Temperature 1.25 Carrier Detect Data Slicer 1.0 0 50 100 0.75 - 50 0 50 100 TA, AMBIENT TEMPERATURE (C) TA, AMBIENT TEMPERATURE (C) 12 MOTOROLA ANALOG IC DEVICE DATA MC13173 APPLICATIONS INFORMATION The MC13173 transceiver is specially designed to operate from a 32.768 kHz reference which is readily available in most computer applications. The frequency synthesizer on chip generates a receiver local oscillator frequency and the transmit mark and space frequencies from this fixed reference frequency, eliminating the need for additional crystals or manual tuning. Large divide ratios are needed to generate these frequencies, however. For example, the receiver LO frequency is 368.5 times the 32.768 kHz reference frequency. This requires that the reference frequency be both accurate and stable. A two percent error in the reference frequency would pull the LO off frequency by over 240 kHz, putting the IF frequency out of the usable bandwidth of the filters and discriminator. For this reason, a 32.768 kHz oscillator circuit has been included on the demonstration board design. Although TTL crystal oscillators are available, this oscillator circuit uses an inexpensive tuning fork crystal and a hex inverter to generate a square wave reference frequency, which is then filtered and level adjusted to a 1.0 Vp-p triangle wave to drive pin 32. A TTL Clock Oscillator could also be used with the filter circuit as shown. Frequency Synthesizer The recommended op amp for the external loop filter is the MC33202. For low voltage operation, (VCC 3.3 V) an op amp that is rail-to-rail on both the input and output is advisable to obtain the widest possible output voltage range without distortion. Sufficient distortion from the op amp such as phase reversal on the output caused by overdriving the inputs could prevent the loop from locking to the reference. In debugging the loop filter, it is important to note that the FSK Modulator phase locked loop will not lock until the Master VCO is locked to the reference. If the application circuit in Figure 15 is used, both loops should lock without the need for any additional tweaking. Since the VCO has 2.0 MHz of range using the MV209 varactor diode (see Figure 11), neither precision components nor tuning should be required. To ensure both loops are operating properly, first evaluate each VCO with the loop open and a voltage equal to VCC/2 applied to the resistor in series with the varactor. Since there is a relatively small capacitance (<40 pF) in series with the LC tank circuit, the VCO pin is sensitive to any parasitic capacitance. Thus when using a standard oscilloscope probe having 10 to 20 pF capacitance it is difficult to measure the VCO frequency without shifting its frequency. A low capacitance FET probe used with a frequency counter will enable you to accurately measure the VCO frequency without altering it in the process. The free running frequency of the VCO should be approximately on frequency when the loop is open and the varactor is biased at mid-supply. The VCO for the Master PLL should run at 12.05 MHz. The free running frequency of the FSK Modulator should be at 13.72 MHz, midway between the two VCO frequencies needed to generate the transmit mark and space frequencies. The FSK Modulator loop is only active when the transmitter is enabled and the device is in the communications mode (see Tables 1 & 2). If either the "T" pin is low or the "E" pin is high, the VCO will be off and you will see no oscillation on Pin 29. Once the loops are closed, the VCO frequencies should track the reference frequency within the hold-in range of the loop. Although the FSK Modulator loop is dependent on the Master VCO, the Master VCO is completely independent of the FSK Modulator. In fact, the FSK Modulator can be powered down (see Table 2) without affecting the Master VCO operation. In the application circuit in Figure 15 a single reference voltage for both op amps in the loop filters is provided by two diodes to VCC. If the Master VCO is affected by the FSK Modulator loop, this generally indicates a problem with the common reference voltage to the op amp, and may mean the diodes are in backwards. Once the loops are closed you should see a phase detector output such as is shown in the Pin Function Description in Table 3. If the VCO was on frequency when the loop was open, the phase detector outputs should swing around mid supply and not hit against either the positive or negative rail. Latching to VCC or VEE may indicate the loop filter circuitry is not implemented correctly. Due to the digital design of the phase detectors, the transmitter can only transition between mark and space frequencies on a clock edge. On the receive side this may be seen as a double image on the detector output, with a discrete time delay which does not vary with the frequency of the data input (see Figure 10). This is a normal consequence of using a digital phase detector and should not be confused with jitter from the data slicer. Figure 10. Receive Data Output (Data Transmitted from Companion MC13173) Transmitter The light emitting diode (LED) driver in the transmitter is capable of 6.0 to 10 mA of pull-up current. Selection of the external transistor and biasing resistor will depend on the LEDs used. Typical infrared LEDs require 50 to 100 mA of current and have a forward voltage of 1.5V. Sufficient current is needed to obtain the maximum power output without distorting the output by overdriving the LED. Key specifications include rise and fall time, wavelength, beam width (generally given in half-angle), maximum power output and efficiency. Choice of wavelengths is generally determined by cost and power efficiency, which may vary between vendors. The LEDs used in this application are at 880 nm and were chosen for best efficiency. However LEDs in general are very inefficient, converting only 1 or 2 percent of the electrical power into optical power. Multiple LEDs can be used to increase transceiver range. MOTOROLA ANALOG IC DEVICE DATA 13 MC13173 Disabling the transmitter via the data bus turns off the output of the LED driver, removing the base current from the external transistor and thereby turning off the IR LED. Because of the high current drawn by the LED, this offers considerable power savings when the transmitter is not in use and can be easily controlled by a microcontroller with no additional circuitry. In the "A/V" transmit mode, the data output is on/off keyed, with the LED on for a data high, and off for a data low. It is a baseband signal, with no carrier present (see Figure 11). Figure 11. LED Driver Output in A/V Mode harmonics. In the application circuit in Figure 15, Toko filters with a bandwidth of 330 kHz or 360 kHz are recommended to accommodate higher data rates. If the IF filters are too narrow, the recovered signal may have noise on the peaks (see Figure 12). Figure 12. Receive Data Output Receiver The receiver portion of the MC13173 is similar to the design of Motorola's MC13156 Wideband FM Receiver. Instead of using the mixer to downconvert from a higher RF frequency, this application is designed to upconvert the 1.372 MHz input to a 10.7 MHz IF. The wide deviation, relative to the RF input frequency, requires a low Q tuned circuit to recover this bandwidth: Q [ BWfc 3 dB , where f c + 1.372 MHz The RSSI has over 70 dB of dynamic range and 20 A of current range. The RSSI output provides the input to the carrier detect comparator (see Figure 13) and a logarithmic output proportional to the input signal level. It can, therefore, be used to recover amplitude shift keyed (ASK) data. The key specifications for the infrared detectors are response time, sensitivity, acceptance angle, and wavelength. Some vendors offer detectors in a black package with a built-in daylight filter. Although the transparent packages offer better sensitivity, the detectors with the daylight filter offer a much better signal to noise ratio. Response time (or maximum frequency) of the system is generally limited by the capability of the emitters rather than the detectors. For this application, a rise and fall time of 500 ns is sufficient. Design and Layout Considerations Although the frequencies in this design are low by RF standards, careful layout and good decoupling are still good practice. The high gain limiter and IF blocks should be decoupled as shown in the application circuit as near the IC as possible for best receiver performance. Also the TTL levels from the reference oscillator and the wide current swing applied to the IR LEDs can easily be picked up on VCC, creating problems for the sensitive phase detector circuits and receiver RF inputs. Avoid long parallel traces and use plenty of decoupling to keep the supply rail clean. By Carson's Rule, the BW = 2(fdev + fmod). Since for mark/space frequencies of 1.317 MHz and 1.427 MHz the deviation is fixed at 50 kHz, the bandwidth for a 50 kHz square wave (100 kbps) would be 200 kHz, and the tuned input requires a Q of less than 7. The low Q of the tank circuit reduces both the selectivity and the sensitivity of the receiver. For a Q of 7, the resistor required across the 56 H inductor can be calculated: R = QXL = (7) * (2) * (1.372 E6) * (56 E-6) R = 3.3 k The 10.7 MHz ceramic filters also need to be wide enough to pass the full frequency range which will include some 14 MOTOROLA ANALOG IC DEVICE DATA MC13173 Typical Performance (Measured using Application Circuit in Figure 15) Figure 13. RSSI Output Current versus RF Input Level 30 RSSI OUTPUT CURRENT ( Adc) 25 20 15 10 5.0 - 140 16 15 VCO FREQUENCY, (MHz) 14 Figure 14. VCO Frequency versus Varactor Voltage FSK Modulator 13 12 Master PLL 11 10 -120 - 100 - 80 - 60 - 40 - 20 0 20 9.0 - 0.5 0 0.5 1.0 1.5 2.0 2.5 3.00 3.5 RF INPUT LEVEL (dBm) VARACTOR VOLTAGE (V) Figure 15. Application Circuit MC33202 VCC 110 k 10 nF 1.0 nF 100 k X1 2.0 M 220 k 24 k 220 k 10 k VEE 100 nF VCC 1N4001 VCC 10 p 3.9 H 270 p VCC 36 k VCC 0.68 + F MV209 VCC 470 p 4.7 H VCC 10 k 10 k 100 p 8.2 k SFH206K 33 n 56 H 3.6 k 180 p 2.0 k 2.2 n NOTES: 1) F1 & F2 - 10.7 MHz ceramic filter, Toko 107MA-AE-10 1.0 n (360 kHz), Toko 107M0 AE-10 (330 kHz) or equivalent. 2) Tunable shielded inductors: 56 H Toko A119ANS-T1042Z 1.0 H Toko 292KNS-T1372Z 82 H Toko A119ANS-T1044Z 1.5 H Toko 292KNS-T1373Z 3) Crystal - 32.768 kHz C - Type tuning fork crystal. Digikey part number SE3201 or equivalent. 4) LEDs and Detectors SFH484-2, SFH485-2 and SFH206K are made by Siemens. 5) Optimum bias resistor depends on the LEDs used. 6) May be fixed or tunable. 1.0 n VCC 510 VCC 82 H 390 p 220 p MPF102 VCC F1 8 9 16 17 VCC VCC 110 k 1.0 nF 100 k 24 k 1.0 k VCC MV209 VCC 10 k SFH484-2 SFH485-2 1.0 n 10 k 100 H (See Note 6) 10 + VCC 100 nF VCC 1.0 + MC74HCU04 10 nF VCC 20 k VCC 200 p 10 k 20 k 62 k 32 1 25 24 MPS3904 VV 100 n CC CC 3.0 k VCC 100 n 2.2 M 15 k 33 n 10 k VCC VCC VCC 2.2 k 10 k 100 n 10 (See Note 5) 1.0 F MC13173 150 p 1.5 110 k VCC 47 k 100 n VCC F2 1.0 n 100 n 1.0 n 0.01 F MOTOROLA ANALOG IC DEVICE DATA 15 MC13173 Figure 16. Detailed Internal Block Diagram 32K 32 CLK_DIV2 D_en 12M 1 D 27 E 26 MaPLL 31 PFD DIV67 2 VEE1 3R 4 RFin1 5 RFin2 6 MIXout MXR OSC DIV11 PFD 7 VCC1 8 IFin 9 IFdec1 10 IFdec2 E_en TxPLL 30 IF DIV12_13 DIV10 LPF_DRV OSC 11 IFout 12 VCC2 13 LIMin 14 LIMdec1 15 LIMdec2 LIM 16 RSSI RSSI LED Feedback 24 LED Driver 25 T 28 14M 29 17 Carrier Detect DET 18 Quad Coil 19 Demod 20 DSin 21 VEE2 DS 22 DATAout 23 VEE3 16 MOTOROLA ANALOG IC DEVICE DATA MC13173 OUTLINE DIMENSIONS FTB SUFFIX PLASTIC TQFP PACKAGE CASE 873-01 L 24 25 17 16 S D S 0.20 (0.008) M C A-B 0.05 (0.002) A-B -A- L -B- B 0.20 (0.008) M V H A-B S D S DETAIL A 32 1 8 9 B P B -D- A 0.20 (0.008) M C A-B 0.05 (0.002) A-B S 0.20 (0.008) M -A-,-B-,-D- S D S DETAIL A F H A-B S D S BASE METAL M DETAIL C J N D 0.20 (0.008) M CE -C- SEATING PLANE -H- H G M DATUM PLANE 0.01 (0.004) C A-B S D S SECTION B-B VIEW ROTATED 90 CLOCKWISE U T -H- DATUM PLANE R K X DETAIL C Q NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DATUM PLANE -H- IS LOCATED AT BOTTOM OF LEAD AND IS COINCIDENT WITH THE LEAD WHERE THE LEAD EXITS THE PLASTIC BODY AT THE BOTTOM OF THE PARTING LINE. 4. DATUMS -A-, -B- AND -D- TO BE DETERMINED AT DATUM PLANE -H-. 5. DIMENSIONS S AND V TO BE DETERMINED AT SEATING PLANE -C-. 6. DIMENSIONS A AND B DO NOT INCLUDE MOLD PROTRUSION. ALLOWABLE PROTRUSION IS 0.25 (0.010) PER SIDE. DIMENSIONS A AND B DO INCLUDE MOLD MISMATCH AND ARE DETERMINED AT DATUM PLANE -H-. 7. DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.08 (0.003) TOTAL IN EXCESS OF THE D DIMENSION AT MAXIMUM MATERIAL CONDITION. DAMBAR CANNOT BE LOCATED ON THE LOWER RADIUS OR THE FOOT. DIM A B C D E F G H J K L M N P Q R S T U V X MILLIMETERS MIN MAX 7.10 6.95 7.10 6.95 1.60 1.40 0.273 0.373 1.50 1.30 -- 0.273 0.80 BSC 0.20 -- 0.119 0.197 0.57 0.33 5.6 REF 8 6 0.119 0.135 0.40 BSC 5 10 0.15 0.25 8.85 9.15 0.15 0.25 5 11 8.85 9.15 1.0 REF INCHES MIN MAX 0.274 0.280 0.274 0.280 0.055 0.063 0.010 0.015 0.051 0.059 -- 0.010 0.031 BSC 0.008 -- 0.005 0.008 0.013 0.022 0.220 REF 8 6 0.005 0.005 0.016 BSC 5 10 0.006 0.010 0.348 0.360 0.006 0.010 5 11 0.348 0.360 0.039 REF MOTOROLA ANALOG IC DEVICE DATA 17 MC13173 Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. "Typical" parameters which may be provided in Motorola data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including "Typicals" must be validated for each customer application by customer's technical experts. Motorola does not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and hold Motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer. How to reach us: USA / EUROPE / Locations Not Listed: Motorola Literature Distribution; P.O. Box 20912; Phoenix, Arizona 85036. 1-800-441-2447 or 602-303-5454 MFAX: RMFAX0@email.sps.mot.com - TOUCHTONE 602-244-6609 INTERNET: http://Design-NET.com JAPAN: Nippon Motorola Ltd.; Tatsumi-SPD-JLDC, 6F Seibu-Butsuryu-Center, 3-14-2 Tatsumi Koto-Ku, Tokyo 135, Japan. 03-81-3521-8315 ASIA/PACIFIC: Motorola Semiconductors H.K. Ltd.; 8B Tai Ping Industrial Park, 51 Ting Kok Road, Tai Po, N.T., Hong Kong. 852-26629298 18 *MC13173/D* MOTOROLA ANALOG IC DEVICE DATA MC13173/D |
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