TMP03FRUZ-REEL7

a Serial Digital Output Thermometers TMP03/TMP04* FEATURES Low Cost 3-Pin Package Modulated Serial Digital Output Proportional to Temperature
1.5C Accuracy (typ) from –25C to +100C Specified –40C to +100C, Operation to 150C Power Consumption 6.5 mW Max at 5 V Flexible Open-Collector Output on TMP03 CMOS/TTL-Compatible Output on TMP04 Low Voltage Operation (4.5 V to 7 V) APPLICATIONS Isolated Sensors Environmental Control Systems Computer Thermal Monitoring Thermal Protection Industrial Process Control Power System Monitors FUNCTIONAL BLOCK DIAGRAM TMP03/TMP04 TEMPERATURE SENSOR VPTAT DIGITAL MODULATOR VREF 1 2 3 DOUT V+ GND PACKAGE TYPES AVAILABLE TO-92 GENERAL DESCRIPTION The TMP03/TMP04 are monolithic temperature detectors that generate a modulated serial digital output that varies in direct proportion to the temperature of the device. An onboard sensor generates a voltage precisely proportional to absolute temperature which is compared to an internal voltage reference and input to a precision digital modulator. The ratiometric encoding format of the serial digital output is independent of the clock drift errors common to most serial modulation techniques such as voltage-to-frequency converters. Overall accuracy is ± 1.5°C (typical) from –25°C to +100°C, with excellent transducer linearity. The digital output of the TMP04 is CMOS/TTL compatible, and is easily interfaced to the serial inputs of most popular microprocessors. The open-collector output of the TMP03 is capable of sinking 5 mA. The TMP03 is best suited for systems requiring isolated circuits utilizing optocouplers or isolation transformers. The TMP03 and TMP04 are specified for operation at supply voltages from 4.5 V to 7 V. Operating from 5 V, supply current (unloaded) is less than 1.3 mA. TMP03/TMP04 1 2 3 DOUT V+ GND BOTTOM VIEW (Not to Scale) SO-8 and RU-8 (TSSOP) DOUT 1 V+ 2 8 NC TMP03/ TMP04 7 NC TOP VIEW 6 NC (Not to Scale) 5 NC NC 4 GND 3 NC = NO CONNECT The TMP03/TMP04 are rated for operation over the –40°C to +100°C temperature range in the low cost TO-92, SO-8, and TSSOP-8 surface mount packages. Operation extends to 150°C with reduced accuracy. (continued on page 4) *Patent pending. REV. A 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 © Analog Devices, Inc., 2002 TMP03/TMP04–SPECIFICATIONS TMP03F (V+ = 5 V, –40C ≤ T ≤ 100C, unless otherwise noted.) A Parameter Symbol ACCURACY Temperature Error Temperature Linearity Long-Term Stability Nominal Mark-Space Ratio Nominal T1 Pulsewidth Power Supply Rejection Ratio Conditions –25°C < TA < +100°C1 –40°C < TA < –25°C1 T1/T2 T1 PSRR 1000 Hours at 125°C TA = 0°C Over Rated Supply TA = 25°C OUTPUTS Output Low Voltage Output Low Voltage VOL VOL Output Low Voltage VOL Digital Output Capacitance Fall Time Device Turn-On Time COUT tHL ISINK = 1.6 mA ISINK = 5 mA 0°C < TA < 100°C ISINK = 4 mA –40°C < TA < 0°C (Note 2) See Test Load V+ ISY Unloaded POWER SUPPLY Supply Range Supply Current Min Typ Max Unit 1.5 2.0 0.5 0.5 58.8 10 0.7 4.0 5.0 1.4 °C °C °C °C % ms °C/V 0.2 2 V V 2 V 15 150 20 4.5 pF ns ms 0.9 7 1.3 V mA Typ Max Unit 1.0 1.5 2.0 0.5 0.5 58.8 10 0.7 3.0 4.0 5.0 °C °C °C °C °C % ms °C/V NOTES 1 Maximum deviation from output transfer function over specified temperature range. 2 Guaranteed but not tested. Specifications subject to change without notice. Test Load 10 kΩ to 5 V Supply, 100 pF to Ground TMP04F (V+ = 5 V, –40C ≤ TA ≤ 100C, unless otherwise noted.) Parameter Symbol ACCURACY Temperature Error Temperature Linearity Long-Term Stability Nominal Mark-Space Ratio Nominal T1 Pulsewidth Power Supply Rejection Ratio OUTPUTS Output High Voltage Output Low Voltage Digital Output Capacitance Fall Time Rise Time Device Turn-On Time POWER SUPPLY Supply Range Supply Current Conditions Min TA = 25°C –25°C < TA < +100°C1 –40°C < TA < –25°C1 T1/T2 T1 PSRR 1000 Hours at 125°C TA = 0°C Over Rated Supply TA = 25°C VOH VOL COUT tHL tLH IOH = 800 µA IOL = 800 µA (Note 2) See Test Load See Test Load V+ ISY Unloaded 1.2 V+ –0.4 0.4 15 200 160 20 4.5 0.9 7 1.3 V V pF ns ns ms V mA NOTES 1 Maximum deviation from output transfer function over specified temperature range. 2 Guaranteed but not tested. Specifications subject to change without notice. Test Load 100 pF to Ground –2– REV. A TMP03/TMP04 ABSOLUTE MAXIMUM RATINGS* ORDERING GUIDE Maximum Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . 9 V Maximum Output Current (TMP03 DOUT) . . . . . . . . . 50 mA Maximum Output Current (TMP04 DOUT) . . . . . . . . . 10 mA Maximum Open-Collector Output Voltage (TMP03) . . . 18 V Operating Temperature Range . . . . . . . . . . –55°C to +150°C Dice Junction Temperature . . . . . . . . . . . . . . . . . . . . . . 175°C Storage Temperature Range . . . . . . . . . . . . –65°C to +160°C Lead Temperature (Soldering, 60 sec) . . . . . . . . . . . . . 300°C Model Accuracy at 25C Temperature Range Package TMP03FT9 TMP03FS TMP03FRU TMP04FT9 TMP04FS ± 3.0 ± 3.0 ± 3.0 ± 3.0 ± 3.0 XIND XIND XIND XIND XIND TO-92 SO-8 TSSOP-8 TO-92 SO-8 *CAUTION 1 Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation at or above this specification is not implied. Exposure to the above maximum rating conditions for extended periods may affect device reliability. 2 Digital inputs and outputs are protected, however, permanent damage may occur on unprotected units from high-energy electrostatic fields. Keep units in conductive foam or packaging at all times until ready to use. Use proper antistatic handling procedures. 3 Remove power before inserting or removing units from their sockets. Package Type TO-92 (T9) SO-8 (S) TSSOP (RU) JA 1 162 1581 2401 JC Units 120 43 43 °C/W °C/W °C/W NOTE 1 ΘJA is specified for device in socket (worst case conditions). CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the TMP03 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. REV. A –3– WARNING! ESD SENSITIVE DEVICE TMP03/TMP04 (continued from page 1) The TMP03 is a powerful, complete temperature measurement system with digital output, on a single chip. The onboard temperature sensor follows in the footsteps of the TMP01 low power programmable temperature controller, offering excellent accuracy and linearity over the entire rated temperature range without correction or calibration by the user. The sensor output is digitized by a first-order sigma-delta modulator, also known as the “charge balance” type analog-todigital converter. (See Figure 1.) This type of converter utilizes time-domain oversampling and a high accuracy comparator to deliver 12 bits of effective accuracy in an extremely compact circuit. ⌺⌬ MODULATOR INTEGRATOR COMPARATOR VOLTAGE REF AND VPTAT 1-BIT DAC CLOCK GENERATOR DIGITAL FILTER TMP03/04 OUT (SINGLE-BIT) avoids major error sources common to other modulation techniques, as it is clock-independent. Output Encoding Accurate sampling of an analog signal requires precise spacing of the sampling interval in order to maintain an accurate representation of the signal in the time domain. This dictates a master clock between the digitizer and the signal processor. In the case of compact, cost-effective data acquisition systems, the addition of a buffered, high speed clock line can represent a significant burden on the overall system design. Alternatively, the addition of an onboard clock circuit with the appropriate accuracy and drift performance to an integrated circuit can add significant cost. The modulation and encoding techniques utilized in the TMP03 avoid this problem and allow the overall circuit to fit into a compact, 3-pin package. To achieve this, a simple, compact onboard clock and an oversampling digitizer that is insensitive to sampling rate variations are used. Most importantly, the digitized signal is encoded into a ratiometric format in which the exact frequency of the TMP03’s clock is irrelevant, and the effects of clock variations are effectively canceled upon decoding by the digital filter. The output of the TMP03 is a square wave with a nominal frequency of 35 Hz (± 20%) at 25°C. The output format is readily decoded by the user as follows: Figure 1. TMP03 Block Diagram Showing First-Order Sigma-Delta Modulator Basically, the sigma-delta modulator consists of an input sampler, a summing network, an integrator, a comparator, and a 1-bit DAC. Similar to the voltage-to-frequency converter, this architecture creates in effect a negative feedback loop whose intent is to minimize the integrator output by changing the duty cycle of the comparator output in response to input voltage changes. The comparator samples the output of the integrator at a much higher rate than the input sampling frequency, called oversampling. This spreads the quantization noise over a much wider band than that of the input signal, improving overall noise performance and increasing accuracy. The modulated output of the comparator is encoded using a circuit technique (patent pending) which results in a serial digital signal with a mark-space ratio format that is easily decoded by any microprocessor into either degrees centigrade or degrees Fahrenheit values, and readily transmitted or modulated over a single wire. Most importantly, this encoding method neatly T1 T2 Figure 2. TMP03 Output Format  400 × T1  Temperature (°C) = 235 −   T2   720 × T1  Temperature (°F) = 455 −   T2  The time periods T1 (high period) and T2 (low period) are values easily read by a microprocessor timer/counter port, with the above calculations performed in software. Since both periods are obtained consecutively, using the same clock, performing the division indicated in the above formulas results in a ratiometric value that is independent of the exact frequency of, or drift in, either the originating clock of the TMP03 or the user’s counting clock. –4– REV. A TMP03/TMP04 Table I. Counter Size and Clock Frequency Effects on Quantization Error Maximum Count Available Maximum Temp Required Maximum Frequency Quantization Error (25C) Quantization Error (77F) 4096 8192 16384 125°C 125°C 125°C 94 kHz 188 kHz 376 kHz 0.284°C 0.142°C 0.071°C 0.512°F 0.256°F 0.128°F with no load. In the TO-92 package mounted in free air, this accounts for a temperature increase due to self-heating of Optimizing Counter Characteristics Counter resolution, clock rate, and the resultant temperature decode error that occurs using a counter scheme may be determined from the following calculations: ∆T = PDISS × θJA = 4.5 mW × 162°C/W = 0.73°C (1.3°F) For a free-standing surface-mount TSSOP package, the temperature increase due to self-heating would be 1. T1 is nominally 10 ms, and compared to T2 is relatively insensitive to temperature changes. A useful worst-case assumption is that T1 will never exceed 12 ms over the specified temperature range. ∆T = PDISS × θJA = 4.5 mW × 240°C/W = 1.08°C (1.9°F) In addition, power is dissipated by the digital output which is capable of sinking 800 µA continuous (TMP04). Under full load, the output may dissipate T1 max = 12 ms Substituting this value for T1 in the formula, temperature (°C) = 235 – ([T1/T2] × 400), yields a maximum value of T2 of 44 ms at 125°C. Rearranging the formula allows the maximum value of T2 to be calculated at any maximum operating temperature:  T2  P DISS = (0.6 V )(0.8 mA)   T1 + T 2  For example, with T2 = 20 ms and T1 = 10 ms, the power dissipation due to the digital output is approximately 0.32 mW with a 0.8 mA load. In a free-standing TSSOP package, this accounts for a temperature increase due to output self-heating of T2 (Temp) = (T1max × 400)/(235 – Temp) in seconds 2. We now need to calculate the maximum clock frequency we can apply to the gated counter so it will not overflow during T2 time measurement. The maximum frequency is calculated using: ∆T = PDISS × ΘJA = 0.32 mW × 240°C/W = 0.08°C (0.14°F) This temperature increase adds directly to that from the quiescent dissipation and affects the accuracy of the TMP03 relative to the true ambient temperature. Alternatively, when the same package has been bonded to a large plate or other thermal mass (effectively a large heatsink) to measure its temperature, the total self-heating error would be reduced to approximately Frequency (max) = Counter Size/ (T2 at maximum temperature) Substituting in the equation using a 12-bit counter gives, Fmax = 4096/44 ms ⯝ 94 kHz. 3. Now we can calculate the temperature resolution, or quantization error, provided by the counter at the chosen clock frequency and temperature of interest. Again, using a 12-bit counter being clocked at 90 kHz (to allow for ~5% temperature over-range), the temperature resolution at 25°C is calculated from: ∆T = PDISS × ΘJC = (4.5 mW + 0.32 mW) × 43°C/W = 0.21°C (0.37°F) Calibration The TMP03 and TMP04 are laser-trimmed for accuracy and linearity during manufacture and, in most cases, no further adjustments are required. However, some improvement in performance can be gained by additional system calibration. To perform a single-point calibration at room temperature, measure the TMP03 output, record the actual measurement temperature, and modify the offset constant (normally 235; see the Output Encoding section) as follows: Quantization Error (°C) = 400 × ([Count1/Count2] – [Count1 – 1]/[Count2 + 1]) Quantization Error (°F) = 720 × ([Count1/Count2] – [Count1 – 1]/[Count2 + 1]) where, Count1 = T1max × Frequency, and Count2 = T2 (Temp) × Frequency. At 25°C this gives a resolution of better than 0.3°C. Note that the temperature resolution calculated from these equations improves as temperature increases. Higher temperature resolution will be obtained by employing larger counters as shown in Table I. The internal quantization error of the TMP03 sets a theoretical minimum resolution of approximately 0.1°C at 25°C. Offset Constant = 235 + (TOBSERVED – TTMP03OUTPUT) A more complicated 2-point calibration is also possible. This involves measuring the TMP03 output at two temperatures, Temp1 and Temp2, and modifying the slope constant (normally 400) as follows: Slope Constant = Self-Heating Effects The temperature measurement accuracy of the TMP03 may be degraded in some applications due to self-heating. Errors introduced are from the quiescent dissipation, and power dissipated by the digital output. The magnitude of these temperature errors is dependent on the thermal conductivity of the TMP03 package, the mounting technique, and effects of airflow. Static dissipation in the TMP03 is typically 4.5 mW operating at 5 V REV. A Temp 2 − Temp1  T1 @ Temp1   T1 @ Temp 2    −   T 2 @ Temp1  T 2 @ Temp 2  where T1 and T2 are the output high and output low times, respectively. –5– TMP03/TMP04–Typical Performance Characteristics 1.05 70 OUTPUT FREQUENCY – Hz NORMALIZED OUTPUT FREQUENCY V+ = 5V RLOAD = 10k 60 50 40 30 20 10 0 –75 –25 25 75 125 1.04 TA = 25C RLOAD = 10k 1.03 1.02 1.01 1.00 0.99 0.98 0.97 4.5 175 5 5.5 6 6.5 7 7.5 SUPPLY VOLTAGE – Volts TEMPERATURE – C TPC 4. Normalized Output Frequency vs. Supply Voltage TPC 1. Output Frequency vs. Temperature 45 VOLTAGE SCALE = 2V/DIV 35 T2 30 TIME – ms SAMPLE RUNNING: 50.0MS/s VS = 5V RLOAD = 10k 40 25 20 15 T1 10 (T ) CH 1 +WIDTH s Wfm DOES NOT CROSS REF TA = 25 C VDD = 5V CH 1 –WIDTH s Wfm DOES NOT CROSS REF CLOAD = 100pF RLOAD = 1k CH 1 RISE 500ns CH 1 FALL s NO VALID EDGE 5 TIME SCALE = 1s/DIV 0 –75 –25 25 75 125 175 TEMPERATURE – C TPC 5. TMP03 Output Rise Time at 25 °C TPC 2. T1 and T2 Times vs. Temperature SAMPLE RUNNING: 50.0MS/s (T ) TA = 25 C VDD = 5V CH 1 +WIDTH s Wfm DOES NOT CROSS REF VOLTAGE SCALE = 2V/DIV VOLTAGE SCALE = 2V/DIV RUNNING: 200MS/s ET CH 1 –WIDTH s Wfm DOES NOT CROSS REF CLOAD = 100pF RLOAD = 1k CH 1 RISE s NO VALID EDGE CH 1 FALL 209.6ns TIME SCALE = 250ns/DIV SAMPLE (T ) CH 1 +WIDTH s Wfm DOES NOT CROSS REF TA = 125 C VDD = 5V CH 1 –WIDTH s Wfm DOES NOT CROSS REF CLOAD = 100pF RLOAD = 1k CH 1 RISE 5380ns CH 1 FALL s NO VALID EDGE TIME SCALE = 1s/DIV TPC 3. TMP03 Output Fall Time at 25 °C TPC 6. TMP03 Output Rise Time at 125 °C –6– REV. A TMP03/TMP04 (T ) EDGE SLOPE CH 1 +WIDTH s Wfm DOES NOT CROSS REF CH 1 –WIDTH s Wfm DOES NOT CROSS REF TA = 125 C VDD = 5V CH 1 RISE s NO VALID EDGE CH 1 FALL 139.5ns CLOAD = 100pF RLOAD = 1k CH 1 –WIDTH s Wfm DOES NOT CROSS REF CLOAD = 100pF RLOAD = 0 CH 1 FALL s NO VALID EDGE SAMPLE RUNNING: 200MS/s ET (T ) CH 1 RISE s NO VALID EDGE CH 1 FALL 127.6ns (T ) CH 1 +WIDTH s Wfm DOES NOT CROSS REF TA = 125 C VDD = 5V VOLTAGE SCALE = 2V/DIV CH 1 +WIDTH s Wfm DOES NOT CROSS REF CH 1 –WIDTH s Wfm DOES NOT CROSS REF CLOAD = 100pF RLOAD = 0 CH 1 RISE 110.6ns TPC 10. TMP04 Output Rise Time at 25 °C SAMPLE TA = 25 C VDD = 5V CH 1 +WIDTH s Wfm DOES NOT CROSS REF TIME SCALE = 250ns/DIV TPC 7. TMP03 Output Fall Time at 125 °C VOLTAGE SCALE = 2V/DIV (T ) TA = 25 C VDD = 5V TIME SCALE = 250ns/DIV RUNNING: 200MS/s ET SAMPLE RUNNING: 200MS/s ET SAMPLE VOLTAGE SCALE = 2V/DIV VOLTAGE SCALE = 2V/DIV RUNNING: 200MS/s ET CH 1 –WIDTH s Wfm DOES NOT CROSS REF CLOAD = 100pF RLOAD = 0 CH 1 RISE 149.6ns CH 1 FALL s NO VALID EDGE TIME SCALE = 250ns/DIV TIME SCALE = 250ns/DIV TPC 8. TMP04 Output Fall Time at 25 °C TPC 11. TMP04 Output Rise Time at 125 °C 2500 SAMPLE TA = 25C VS = 5V RLOAD = (T ) TA = 125 C VDD = 5V 2000 CH 1 +WIDTH s Wfm DOES NOT CROSS REF FAL L TIME CH 1 –WIDTH s Wfm DOES NOT CROSS REF CLOAD = 100pF RLOAD = 0 TIME – ns VOLTAGE SCALE = 2V/DIV RUNNING: 200MS/s ET CH 1 RISE s NO VALID EDGE 1500 1000 RISE TIME CH 1 FALL 188.0ns 500 TIME SCALE = 250ns/DIV 0 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 LOAD CAPACITANCE – pF TPC 9. TMP04 Output Fall Time at 125 °C REV. A TPC 12. TMP04 Output Rise and Fall Times vs. Capacitive Load –7– TMP03/TMP04 5 5 4 START-UP SUPPLY VOLTAGE – Volts 3 OUTPUT ACCURACY – C START-UP VOLTAGE DEFINED AS OUTPUT READING BEING WITHIN
5C OF OUTPUT AT 4.5V SUPPLY MAXIMUM LIMIT V+ = 5V RLOAD = 10k 2 MEASUREMENTS IN STIRRED OIL BATH 1 TMP03 0 TMP04 –1 –2 –3 4.5 RLOAD = 10k 4 3.5 MINIMUM LIMIT –4 –5 –50 –25 0 50 25 TEMPERATURE – C 75 100 3 –75 125 –25 25 75 125 175 TEMPERATURE – C TPC 16. Start-Up Voltage vs. Temperature TPC 13. Output Accuracy vs. Temperature 1600 TYPICAL VALUES 0, T2 OUTPUT STARTS LOW T1 TEMP C T2 ms T1 ms 1400 –55 25 125 15 20 35 10 10 10 1200 SUPPLY CURRENT – A V+ = 5V RLOAD = 10k T2 0, T1 OUTPUT STARTS HIGH T2 T1 TA = 25C NO LOAD 1000 800 600 400 200 V+ 0 10 20 30 40 50 60 70 80 90 0 100 0 1 2 TIME – ms TPC 14. Start-Up Response 3.5 POWER SUPPLY REJECTION – C/V SUPPLY CURRENT – A 7 8 4 V+ = 5V NO LOAD 1000 950 900 TMP03 850 TMP04 800 750 –75 6 TPC 17. Supply Current vs. Supply Voltage 1100 1050 3 5 4 SUPPLY VOLTAGE – Volts V+ = 4.5V TO 7V RLOAD = 10k 3 2.5 2 1.5 1 0.5 –25 25 75 125 0 –75 175 TEMPERATURE – C –25 25 75 125 175 TEMPERATURE – C TPC 15. Supply Current vs. Temperature TPC 18. Power Supply Rejection vs. Temperature –8– REV. A TMP03/TMP04 20 V+ = 5V DC
50mV AC RLOAD = 10k 18 VOL = 1V V+ = 5V 16 0.5 SINK CURRENT – mA DEVIATION IN TEMPERATURE – C 1 NORMAL PSSR 0 14 12 10 8 –0.5 6 4 –1 1 100 10 1k 10k 100k 1M 2 –75 10M –25 75 25 TEMPERATURE – C FREQUENCY – Hz TPC 19. Power Supply Rejection vs. Frequency 150 TPC 22. TMP03 Open-Collector Sink Current vs. Temperature 105 400 100 V+ = 5V 350 300 ILOAD = 5mA 250 200 150 100 ILOAD = 1mA 75 25  ~ 23 SEC (SOIC, NO SOCKET)  ~ 40 SEC (TO –92, NO SOCKET) 65 60 55 50 TO –92 45 40 35 30 ILOAD = 0.5mA –25 VS = 5V RLOAD = 10k 70 50 0 –75 TRANSITION FROM 100C STIRRED OIL BATH TO STILL 25C AIR 95 90 85 80 OUTPUT TEMPERATURE – C OPEN-COLLECTOR OUTPUT VOLTAGE – mV 125 75 125 25 175 SOIC 0 25 50 75 100 125 150 175 200 225 250 275 300 TEMPERATURE – C TIME – sec TPC 20. TMP03 Open-Collector Output Voltage vs. Temperature TPC 23. Thermal Response Time in Still Air 140 OUTPUT TEMPERATURE – C  TIME CONSTANT – sec V+ = 5V RLOAD = 10k 100 80 60 TO –92 - WITH SOCKET 40 TO –92 - NO SOCKET 100 200 300 400 500 1.25 SEC (SOIC IN SOCKET) 2 SEC (TO –92 IN SOCKET) TRANSITION FROM STILL 25C AIR TO STIRRED 100C OIL BATH 600 700 0 10 20 30 40 50 60 TIME – sec AIR VELOCITY – FPM TPC 21. Thermal Time Constant in Forced Air REV. A   25 0 V+ = 5V RLOAD = 10k TO –92 SOIC - NO SOCKET 20 0 SOIC 100 TRANSITION FROM 100C OIL BATH TO FORCED 25C AIR 120 TPC 24. Thermal Response Time in Stirred Oil Bath –9– TMP03/TMP04 APPLICATIONS INFORMATION Supply Bypassing TMP03 Output Configurations The TMP03 (Figure 5a) has an open-collector NPN output which is suitable for driving a high current load, such as an opto-isolator. Since the output source current is set by the pullup resistor, output capacitance should be minimized in TMP03 applications. Otherwise, unequal rise and fall times will skew the pulsewidth and introduce measurement errors. The NPN transistor has a breakdown voltage of 18 V. Precision analog products, such as the TMP03, require a wellfiltered power source. Since the TMP03 operate from a single 5 V supply, it seems convenient to simply tap into the digital logic power supply. Unfortunately, the logic supply is often a switchmode design, which generates noise in the 20 kHz to 1 MHz range. In addition, fast logic gates can generate glitches hundred of millivolts in amplitude due to wiring resistance and inductance. V+ DOUT If possible, the TMP03 should be powered directly from the system power supply. This arrangement, shown in Figure 3, will isolate the analog section from the logic switching transients. Even if a separate power supply trace is not available, however, generous supply bypassing will reduce supply-line induced errors. Local supply bypassing consisting of a 10 µF tantalum electrolytic in parallel with a 0.1 µF ceramic capacitor is recommended (Figure 4a). TMP03 TMP04 a. b. Figure 5. TMP03 Digital Output Structure The TMP04 has a “totem-pole” CMOS output (Figure 5b) and provides rail-to-rail output drive for logic interfaces. The rise and fall times of the TMP04 output are closely matched, so that errors caused by capacitive loading are minimized. If load capacitance is large, for example when driving a long cable, an external buffer may improve accuracy. See the “Remote Temperature Measurement” section of this data sheet for suggestions. TTL/CMOS LOGIC CIRCUITS +10F TANT 0.1F TMP03/ TMP04 5V POWER SUPPLY Interfacing the TMP03 to Low Voltage Logic Figure 3. Use Separate Traces to Reduce Power Supply Noise The TMP03’s open-collector output is ideal for driving logic gates that operate from low supply voltages, such as 3.3 V. As shown in Figure 6, a pull-up resistor is connected from the low voltage logic supply (2.9 V, 3 V, etc.) to the TMP03 output. Current through the pull-up resistor should be limited to about 1 mA, which will maintain an output LOW logic level of temperature result in 14.2 format 2 * TMP04 output period } .MODULE/RAM/BOOT=0 TEMPERAT; .ENTRY TEMPMEAS; .CONST PRESCALER=4; .CONST TIMFULSCALE=0Xffff; TEMPMEAS: si=PRESCALER; sr0=TIMFULSCALE; dm(0x3FFB)=si; si=TIMFULSCALE; dm(0x3FFC)=si; dm(0x3FFD)=si; imask=0x01; TEST1: if not fi jump TEST1; TEST0: if fi jump TEST0; ena timer; COUNT2: if not fi jump COUNT2; dis timer; ay0=dm(0x3FFC); ar=sr0-ay0; ax0=ar; dm(0x3FFC)=si; ena timer; COUNT1: if fi jump COUNT1; dis timer; ay0=dm(0x3FFC); ar=sr0-ay0; my0=400; mr=ar*my0(uu); ay0=mr0; ar=mr1; af=pass ar; COMPUTE: astat=0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; divq ax0; ax0=0x03AC; ar=ax0-ay0; rts; .ENDMOD; { Beginning TEMPERAT Program } { Entry point of this subroutine } { { { { { { { For timer prescaler } Timer counter full scale } Timer Prescaler set up to 5 } CLKin=10MHz,Timer Period=32.768ms } Timer Counter Register to 65535 } Timer Period Register to 65535 } Unmask Interrupt timer } { Check for FI=1 } { Check for FI=0 to locate transition } { Enable timer, count at a 500ns rate } { Check for FI=1 to stop count } { Save counter=T2 in ALU register } { Reload counter at full scale } { Check for FI=0 to stop count } { Save counter=T1 in ALU register } { { { { { { mr=400*T1 } af=MSW of dividend, ay0=LSW } ax0=16-bit divisor } To clear AQ flag } Division 400*T1/T2 } with 0.3 < T1/T2 < 0.7 } { { { { { Result in ay0 } ax0=235*4 } ar=235-400*T1/T2, result in øC } format 14.2 } End of the subprogram } –14– REV. A TMP03/TMP04 T1 DATA (MICROSECONDS) 5V 2 5 6 9 Q1 Q2 Q3 Q4 20 11 5V VCC 3 1 OUT GND LE 12 15 16 19 Q1 Q2 Q3 Q4 1 20 10 11 D5 D6 D7 D8 3 4 7 8 3 2 5 6 9 Q5 Q6 Q7 Q8 74HC373 D1 D2 D3 D4 1 2 5V 12 15 16 19 T2 DATA (MICROSECONDS) VCC OUT 74HC373 GND LE D1 D2 D3 D4 13 14 17 18 5V 1 10 D5 D6 D7 D8 3 4 7 8 2 5 6 9 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 20 11 VCC 12 15 16 19 74HC373 D1 D2 D3 D4 OUT GND LE 13 14 17 18 5V Q5 Q6 Q7 Q8 1 10 D5 D6 D7 D8 3 4 7 8 2 5 6 9 Q1 Q2 Q3 Q4 13 14 17 18 20 11 VCC 12 15 16 19 Q5 Q6 Q7 Q8 74HC373 LE D1 D2 D3 D4 3 4 7 8 OUT GND 1 10 D5 D6 D7 D8 13 14 17 18 2 74HC08 4 5 6 5V 3 4 5 6 10 11 12 13 14 3 4 5 6 10 11 12 13 14 5V Q0 Q1 Q2 Q3 EN Q0 Q1 Q2 Q3 Q0 Q1 Q2 Q3 EN Q0 Q1 Q2 Q3 1MHZ CLOCK 16 V CC 2 EN 1 16 74HC4520 #1 CLK CLK GND 9 2 15 7 1 20pF 74HC86 4 6 5 5V 10k 0.1F 10F 10pF 5V 74HC4520 #2 EN CLK CLK GND RESET RESET RESET RESET 8 VCC T1 1k 9 8 7 15 5V 20pF 3.9k 5V 15 14 T1 T2 T2 4 VCC 16 A 5 Q 6 B 3 7 Q CLR NC GND 8 74HC4538 12 A 10 11 Q B 13 9 Q NC CLR GND 8 V+ DOUT TMP04 GND Figure 12. A Hardware Interface for the TMP04 Monitoring Electronic Equipment The TMP03 are ideal for monitoring the thermal environment within electronic equipment. For example, the surface-mounted package will accurately reflect the exact thermal conditions which affect nearby integrated circuits. The TO-92 package, on the other hand, can be mounted above the surface of the board, to measure the temperature of the air flowing over the board. The TMP03 and TMP04 measure and convert the temperature at the surface of their own semiconductor chip. When the TMP03 are used to measure the temperature of a nearby heat source, the thermal impedance between the heat source and the TMP03 must be considered. Often, a thermocouple or other temperature sensor is used to measure the temperature of the source REV. A while the TMP03 temperature is monitored by measuring T1 and T2. Once the thermal impedance is determined, the temperature of the heat source can be inferred from the TMP03 output. One example of using the TMP04 to monitor a high power dissipation microprocessor or other IC is shown in Figure 13. The TMP04, in a surface mount package, is mounted directly beneath the microprocessor’s pin grid array (PGA) package. In a typical application, the TMP04’s output would be connected to an ASIC where the pulsewidth would be measured (see the Hardware Interface section of this data sheet for a typical interface schematic). The TMP04 pulse output provides a significant –15– TMP03/TMP04 FAST MICROPROCESSOR, DSP, ETC., IN PGA PACKAGE PGA SOCKET TMP04 IN SURFACE MOUNT PACKAGE PC BOARD Figure 13. Monitoring the Temperature of a High Power Microprocessor Improves System Reliability Thermal Response Time The time required for a temperature sensor to settle to a specified accuracy is a function of the thermal mass of, and the thermal conductivity between, the sensor and the object being sensed. Thermal mass is often considered equivalent to capacitance. Thermal conductivity is commonly specified using the symbol Θ, and can be thought of as thermal resistance. It is commonly specified in units of degrees per watt of power transferred across the thermal joint. Thus, the time required for the TMP03 to settle to the desired accuracy is dependent on the package selected, the thermal contact established in that particular application, and the equivalent power of the heat source. In most applications, the settling time is probably best determined empirically. The TMP03 output operates at a nominal frequency of 35 Hz at 25°C, so the minimum settling time resolution is 27 ms. C00334–0–1/02(A) advantage in this application because it produces a linear temperature output while needing only one I/O pin and without requiring an A/D converter. OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 3-Pin TO-92 8-Pin SOIC (SO-8) 0.1968 (5.00) 0.1890 (4.80) 0.205 (5.20) 0.175 (4.96) 0.135 (3.43) MIN 0.1574 (4.00) 0.1497 (3.80) 0.210 (5.33) 0.170 (4.38) 0.050 (1.27) MAX SEATING PLANE 5 1 4 0.2440 (6.20) 0.2284 (5.80) PIN 1 0.0196 (0.50) ⴛ 45ⴗ 0.0099 (0.25) 0.0500 (1.27) BSC 0.0688 (1.75) 0.0532 (1.35) 0.0098 (0.25) 0.0040 (0.10) 0.019 (0.482) 0.016 (0.407) 0.500 (12.70) MIN 8 8ⴗ 0.0500 (1.27) 0.0098 (0.25) 0ⴗ 0.0160 (0.41) 0.0075 (0.19) 0.0192 (0.49) 0.0138 (0.35) SEATING PLANE SQUARE 8-Pin TSSOP (RU-8) 0.055 (1.39) 0.045 (1.15) 0.105 (2.66) 0.095 (2.42) 8 0.105 (2.66) 0.080 (2.42) 1 2 3 PRINTED IN U.S.A. 0.122 (3.10) 0.114 (2.90) 0.105 (2.66) 0.080 (2.42) 5 0.177 (4.50) 0.169 (4.30) 0.165 (4.19) 0.125 (3.94) 0.256 (6.50) 0.246 (6.25) 1 BOTTOM VIEW 4 PIN 1 0.0256 (0.65) BSC 0.006 (0.15) 0.002 (0.05) SEATING PLANE –16– 0.0118 (0.30) 0.0075 (0.19) 0.0433 (1.10) MAX 0.0079 (0.20) 0.0035 (0.090) 8ⴗ 0ⴗ 0.028 (0.70) 0.020 (0.50) REV. A