西安交通大学：《工程训练之—工业系统的测量》（英文版）AD590.pdf

ANALOG TWO-Terminal Ic DEVICES Temperature Transducer AD590 FEATURES PIN DESIGNATIONS Linear Current Output: 1 HA/K Wide Range:-55C to+150C Probe Compatible Ceramic Sensor Package Two Terminal Device: Voltage In/Current Out Laser Trimmed to +0.5C Calibration Accuracy(AD590M) Excellent Linearity: =0. 3.C Over Full Range(AD590M CAN Wide Power Supply Range: +4 V to +30 V Sensor isolation from case Low Cost BOTTOM VIEW PRODUCT DESCRIPTION PRODUCT HIGHLIGHTS The AD590 is a two-terminal integrated circuit temperature 1. The AD590 is a calibrated two terminal temperature sensor transducer that produces an output current proportional to requiring only a dc voltage supply (+4 V to +30 V). Costly absolute temperature. For supply voltages between +4 V and transmitters, filters, lead wire compensation and linearization +30 V the device acts as a high impedance, constant current circuits are all unnecessary in applying the device gulator passing 1 HA/K. Laser trimming of the chips thin-film 2. State-of-the-art esistors is used to calibrate the device to 298.2 A output at rimming at the wafer level in conjunc 2982K(+25°C tion with extensive final testing ensures that AD590 units are asily interchange The AD590 should be used in any temperature sensing applica- 3. Superior interface rejection results from the output being a tion below +150.C in which conventional electrical temperature sensors are currently employed. The inherent low cost of a urrent rather than a voltage. In addition, power require ments are low(1.5 mWs@5V@+25C )These features monolithic integrated circuit combined with the elimination of support circuitry makes the AD590 an attractive alternative for make the AD590 easy to apply as a remote sensor many temperature measurement situations. Linearization 4. The high output impedance(>10 MQ) provides excellent ircuitry, precision voltage amplifiers, resistance measuring rejection of supply voltage drift and ripple. For instance, circuitry and cold junction compensation are not needed in hanging the power supply from 5 V to 10 V results in only applying the AD590 a 1 uA maximum current change, or 1C equivalent error In addition to temperature measurement, applications include 5. The AD590 is electrically durable: it will withstand a forward nents. biasing proportional to absolute temperature, lloy a temperature compensation or correction of discrete voltage up to 44 V and a reverse voltage of 20 V. Hence, sup- ply irregularities or pin reversal will not damage the device ate measurement level detection of fluids and anemometry The AD590 is available in chip form making, it suitable for hybrid circuits and fast temperature measurements in protected environments The AD590 is particularly useful in remote sensing applications The device is insensitive to voltage drops over long lines due to its high impedance current output. Any well insulated twisted pair is sufficient for operation hundreds of feet from the eceiving circuitry. The output characteristics also make the 590 easy to multiplex: the current can be switched by a CMOS multiplexer or the supply voltage can be switched by a Information furnished by Analog s believed to be accurate and no responsibilit may result from its use. Ne or other rights of third parties e is granted by implication or Te:617/329.47 WorldWideWebSitehttp://www.ar otherwise under any patent or patent rights of Analog Devices Fax617/326-8703 e Analog Devices, Inc., 1997

PIN DESIGNATIONS REV. B 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. a Two-Terminal IC Temperature Transducer AD590 FEATURES Linear Current Output: 1 mA/K Wide Range: –558C to +1508C Probe Compatible Ceramic Sensor Package Two Terminal Device: Voltage In/Current Out Laser Trimmed to 60.58C Calibration Accuracy (AD590M) Excellent Linearity: 60.38C Over Full Range (AD590M) Wide Power Supply Range: +4 V to +30 V Sensor Isolation from Case Low Cost PRODUCT DESCRIPTION The AD590 is a two-terminal integrated circuit temperature transducer that produces an output current proportional to absolute temperature. For supply voltages between +4 V and +30 V the device acts as a high impedance, constant current regulator passing 1 µA/K. Laser trimming of the chip’s thin-film resistors is used to calibrate the device to 298.2 µA output at 298.2K (+25°C). The AD590 should be used in any temperature sensing application below +150°C in which conventional electrical temperature sensors are currently employed. The inherent low cost of a monolithic integrated circuit combined with the elimination of support circuitry makes the AD590 an attractive alternative for many temperature measurement situations. Linearization circuitry, precision voltage amplifiers, resistance measuring circuitry and cold junction compensation are not needed in applying the AD590. In addition to temperature measurement, applications include temperature compensation or correction of discrete components, biasing proportional to absolute temperature, flow rate measurement, level detection of fluids and anemometry. The AD590 is available in chip form making, it suitable for hybrid circuits and fast temperature measurements in protected environments. The AD590 is particularly useful in remote sensing applications. The device is insensitive to voltage drops over long lines due to its high impedance current output. Any well insulated twisted pair is sufficient for operation hundreds of feet from the receiving circuitry. The output characteristics also make the AD590 easy to multiplex: the current can be switched by a CMOS multiplexer or the supply voltage can be switched by a logic gate output. PRODUCT HIGHLIGHTS 1. The AD590 is a calibrated two terminal temperature sensor requiring only a dc voltage supply (+4 V to +30 V). Costly transmitters, filters, lead wire compensation and linearization circuits are all unnecessary in applying the device. 2. State-of-the-art laser trimming at the wafer level in conjunction with extensive final testing ensures that AD590 units are easily interchangeable. 3. Superior interface rejection results from the output being a current rather than a voltage. In addition, power requirements are low (1.5 mWs @ 5 V @ +25°C.) These features make the AD590 easy to apply as a remote sensor. 4. The high output impedance (>10 MΩ) provides excellent rejection of supply voltage drift and ripple. For instance, changing the power supply from 5 V to 10 V results in only a 1 µA maximum current change, or 1°C equivalent error. 5. The AD590 is electrically durable: it will withstand a forward voltage up to 44 V and a reverse voltage of 20 V. Hence, supply irregularities or pin reversal will not damage the device. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 617/329-4700 World Wide Web Site: http://www.analog.com Fax: 617/326-8703 © Analog Devices, Inc., 1997

AD590–SPECIFICATIONS Model AD590J AD590K Min Typ Max Min Typ Max Units ABSOLUTE MAXIMUM RATINGS Forward Voltage ( E+ or E–) +44 +44 Volts Reverse Voltage (E+ to E–) –20 –20 Volts Breakdown Voltage (Case E+ or E–) ±200 ±200 Volts Rated Performance Temperature Range1 –55 +150 –55 +150 °C Storage Temperature Range1 –65 +155 –65 +155 °C Lead Temperature (Soldering, 10 sec) +300 +300 °C POWER SUPPLY Operating Voltage Range +4 +30 +4 +30 Volts OUTPUT Nominal Current Output @ +25°C (298.2K) 298.2 298.2 µA Nominal Temperature Coefficient 1 1 µA/K Calibration Error @ +25°C 65.0 62.5 °C Absolute Error (Over Rated Performance Temperature Range) Without External Calibration Adjustment 610 65.5 °C With +25°C Calibration Error Set to Zero 63.0 62.0 °C Nonlinearity 61.5 60.8 °C Repeatability2 ±0.1 ±0.1 °C Long-Term Drift3 ±0.1 ±0.1 °C Current Noise 40 40 pA/√Hz Power Supply Rejection +4 V ≤ VS ≤ +5 V 0.5 0.5 µA/V +5 V ≤ VS ≤ +15 V 0.2 0.2 µV/V +15 V ≤ VS ≤ +30 V 0.1 0.1 µA/V Case Isolation to Either Lead 1010 1010 Ω Effective Shunt Capacitance 100 100 pF Electrical Turn-On Time 20 20 µs Reverse Bias Leakage Current4 (Reverse Voltage = 10 V) 10 10 pA PACKAGE OPTIONS TO-52 (H-03A) AD590JH AD590KH Flatpack (F-2A) AD590JF AD590KF NOTES 1 The AD590 has been used at –100°C and +200°C for short periods of measurement with no physical damage to the device. However, the absolute errors specified apply to only the rated performance temperature range. 2 Maximum deviation between +25°C readings after temperature cycling between –55°C and +150°C; guaranteed not tested. 3 Conditions: constant +5 V, constant +125°C; guaranteed, not tested. 4 Leakage current doubles every 10°C. Specifications subject to change without notice. Specifications shown in boldface are tested on all production units at final electrical test. Results from those tests are used to calculate outgoing quality levels. All min and max specifications are guaranteed, although only those shown in boldface are tested on all production units. (@ +258C and VS = +5 V unless otherwise noted) –2– REV. B

AD590 The 590H has 60 u inches of gold plating on its Kovar leads and In the AD590, this PtAT voltage is converted to a PTAT cur to the header. The AD590 chip is eutectically mounted to the o Kovar header. a resistance welder is used to seal the nickel c ent by low temperature coefficient thin-film resistors. The total current of the device is then forced to be a multiple of this header and ultrasonically bonded to with 1 MIL aluminum PTAT current. Referring to Figure 1, the schematic diagram of wire. Kovar composition: 53% iron nominal; 29%+1% nickel the AD590, Q8 and Qll are the transistors that produce the 17%+ 1% cobalt: 0.65% manganese max: 0. 20% silicon ma PTAT voltage R5 and R6 convert the voltage to current. Q10, 0.10% aluminum max: 0. 10% magnesium max: 0.10% zirco whose collector current tracks the colletor currents in Q9 and nium max: 0.10% titanium max: 0.06% carbon max Q11, supplies all the bias and substrate leakage current for the The 590F is a ceramic package with gol rest of the circuit, forcing the total current to be PtAT. R5 and leads, Kovar lid, and chip cavity Solder of 80/20 Aw/Sn com R6 are laser trimmed on the wafer to calibrate the device at position is used for the 1.5 mil thick solder ring under the lid 25°C. The chip cavity has a nickel underlay between the metalization Figure 2 shows the typical V-I characteristic of the circuit at nd the gold plating. The AD590 chip is eutectically mounted +25.C and the temperature extremes in the chip cavity at 410C and ultrasonically bonded to with 1 mil aluminum wire. Note that the chip is in direct contact with the ceramic base not the metal lid. When using the AD590 in die form, the chip substrate must be kept electrically isolated (floating), for correct circuit operation METALIZATION DIAGRAM Figure 1. Schematic Diagram CIRCUIT DESCRIPTIONI +150°c The AD590 uses a fundamental property of the silicon transis tors from which it is made to realize its temperature propor- tional characteristic: if two identical transistors are operated at a 如 +25c constant ratio of collector current densities, r. then the differ 55C ence in their base-emitter voltage will be(kT/q (In r). Since both k, Boltzman's constant and g, the charge of an electron are constant, the resulting voltage is directly proportional to absolute temperature (PTAT) SUPPLY VOLTAGE igure 2. V-1 Plot or a more detailed circuit description see M.P. Timko, "A Two-Terminal IC Temperature Transducer, J. Solid State Circuits. Vol SC-11 P.784-788,Dec.1976 REV. B

AD590 –4– REV. B The 590H has 60 µ inches of gold plating on its Kovar leads and Kovar header. A resistance welder is used to seal the nickel cap to the header. The AD590 chip is eutectically mounted to the header and ultrasonically bonded to with 1 MIL aluminum wire. Kovar composition: 53% iron nominal; 29% ±1% nickel; 17% ± 1% cobalt; 0.65% manganese max; 0.20% silicon max; 0.10% aluminum max; 0.10% magnesium max; 0.10% zirconium max; 0.10% titanium max; 0.06% carbon max. The 590F is a ceramic package with gold plating on its Kovar leads, Kovar lid, and chip cavity. Solder of 80/20 Au/Sn composition is used for the 1.5 mil thick solder ring under the lid. The chip cavity has a nickel underlay between the metalization and the gold plating. The AD590 chip is eutectically mounted in the chip cavity at 410°C and ultrasonically bonded to with 1 mil aluminum wire. Note that the chip is in direct contact with the ceramic base, not the metal lid. When using the AD590 in die form, the chip substrate must be kept electrically isolated, (floating), for correct circuit operation. METALIZATION DIAGRAM CIRCUIT DESCRIPTION1 The AD590 uses a fundamental property of the silicon transistors from which it is made to realize its temperature proportional characteristic: if two identical transistors are operated at a constant ratio of collector current densities, r, then the difference in their base-emitter voltage will be (kT/q)(In r). Since both k, Boltzman’s constant and q, the charge of an electron, are constant, the resulting voltage is directly proportional to absolute temperature (PTAT). 1 For a more detailed circuit description see M.P. Timko, “A Two-Terminal IC Temperature Transducer,” IEEE J. Solid State Circuits, Vol. SC-11, p. 784-788, Dec. 1976. In the AD590, this PTAT voltage is converted to a PTAT current by low temperature coefficient thin-film resistors. The total current of the device is then forced to be a multiple of this PTAT current. Referring to Figure 1, the schematic diagram of the AD590, Q8 and Q11 are the transistors that produce the PTAT voltage. R5 and R6 convert the voltage to current. Q10, whose collector current tracks the colletor currents in Q9 and Q11, supplies all the bias and substrate leakage current for the rest of the circuit, forcing the total current to be PTAT. R5 and R6 are laser trimmed on the wafer to calibrate the device at +25°C. Figure 2 shows the typical V–I characteristic of the circuit at +25°C and the temperature extremes. Figure 1. Schematic Diagram Figure 2. V–I Plot

Understanding the Specifications-AD590 EXPLANATION OF TEMPERATURE SENSOR ERROR VERUS TEMPERATURE: WITH CALIBRATION SPECIFICATIONS ERROR TRIMMED OUT The way in which the AD590 is specified makes it easy to apply Each AD590 is tested for error over the temperature range in a wide variety of different applications. It is important to understand the meaning of the various specifications and the be called the "variance from ptat since it is the maximum difference between the actual current over temperature and a effects of supply voltage and thermal environment on accuracy. PtAT multiplication of the actual current at 25C. This error The AD590 is basically a PTAT (proportional to absolute temperature)current regulator. That is, the output current is consists of a slope error and some curvature, mostly at the temperature extremes. Figure 5 shows a typical AD590K qual to a scale factor times the temperature of the sensor in degrees Kelvin. This scale factor is trimmed to 1 HA/K at the temperature curve before and after calibration error trimming factory, by adjusting the indicated temperature (i. e, the output current) to agree with the actual temperature. This is done with 5 V across the device at a temperature within a few degrees of +25C (298.2K). The device is then packaged and tested for accuracy over temperature CALIBRATION ERROR CALIBRATION ERROR At final factory test the difference between the indicated CALIBRATION temperature and the actual temperature is called the calibration error. Since this is a scale factory error, its contribution to the total error of the device is PTAT. For example, the effect of the TEMPERATURE C specified maximum error of the AD59OL varies from 0.73C at-55C to 1.42C at 150C. Figure 3 shows how an exagger Figure 5. Effect to Scale Factor Trim on Accuracy ated calibration error would vary from the ideal over temperatur ERROR VERSUS TEMPERATURE: NO USER TRIMS Using the AD590 by simply measuring the current, the total error is the"variance from PtaT" described above plus the effect of the calibration error over temperature. For example the AD590L maximum total error varies from 2.33C at-55C to 3.02C at 150C. For simplicity, only the large figure is shown NONLINEARITY Nonlinearity as it applies to the AD590 is the maximum deviation of current over temperature from a best-fit straight line. The nonlinearity of the AD590 over the -55oC to +150oC Figure 3. Calibration Error vs. Temperature range is superior to all conventional electrical temperature The calibration error is a primary contributor to maximum total sensors such as thermocouples. RTDs and thermistors. Figure 6 error in all AD590 grades. However, since it is a scale factor shows the nonlinearity of the typical AD590K from Figure 5 error, it is particularly easy to trim. Figure 4 shows the most elementary way of accomplishing this. To trim this circuit the temperature of the AD590 is measured by a reference tempera ture sensor and r is trimmed so that vr= 1 mV/K at that temperature. Note that when this error is trimmed out at one temperature, its effect is zero over the entire temperature range In most applications there is a current-to-voltage conversion resistor (or, as with a current input ADC, a reference) that can be trimmed for scale factor adjustment Figure 7A shows a circuit in which the nonlinearity is the major contributor to error over temperature. The circuit is trimmed by adjusting RI for a 0 V output with the AD590 at 0oC. R2 is ther 960g adjusted for 10 V out with the sensor at 100.C. Other pairs of temperatures may be used with this procedure as long as they are measured accurately by a reference sensor. Note that for Figure 4. One Temperature Trim +15 V output(150.C)the V+ of the op amp must be greater T(C)=T(K)-2732: Zero on the Kelvin scale is"absolute zero"; there is than 17 V. Also note that v- should be at least -4 V: if v-is lower temperature. ground there is no voltage applied across the device REV B

EXPLANATION OF TEMPERATURE SENSOR SPECIFICATIONS The way in which the AD590 is specified makes it easy to apply in a wide variety of different applications. It is important to understand the meaning of the various specifications and the effects of supply voltage and thermal environment on accuracy. The AD590 is basically a PTAT (proportional to absolute temperature)1 current regulator. That is, the output current is equal to a scale factor times the temperature of the sensor in degrees Kelvin. This scale factor is trimmed to 1 µA/K at the factory, by adjusting the indicated temperature (i.e., the output current) to agree with the actual temperature. This is done with 5 V across the device at a temperature within a few degrees of +25°C (298.2K). The device is then packaged and tested for accuracy over temperature. CALIBRATION ERROR At final factory test the difference between the indicated temperature and the actual temperature is called the calibration error. Since this is a scale factory error, its contribution to the total error of the device is PTAT. For example, the effect of the 1°C specified maximum error of the AD590L varies from 0.73°C at –55°C to 1.42°C at 150°C. Figure 3 shows how an exaggerated calibration error would vary from the ideal over temperature. Figure 3. Calibration Error vs. Temperature The calibration error is a primary contributor to maximum total error in all AD590 grades. However, since it is a scale factor error, it is particularly easy to trim. Figure 4 shows the most elementary way of accomplishing this. To trim this circuit the temperature of the AD590 is measured by a reference temperature sensor and R is trimmed so that VT = 1 mV/K at that temperature. Note that when this error is trimmed out at one temperature, its effect is zero over the entire temperature range. In most applications there is a current-to-voltage conversion resistor (or, as with a current input ADC, a reference) that can be trimmed for scale factor adjustment. Figure 4. One Temperature Trim 1 T(°C) = T(K) –273.2; Zero on the Kelvin scale is “absolute zero”; there is no lower temperature. ERROR VERUS TEMPERATURE: WITH CALIBRATION ERROR TRIMMED OUT Each AD590 is tested for error over the temperature range with the calibration error trimmed out. This specification could also be called the “variance from PTAT” since it is the maximum difference between the actual current over temperature and a PTAT multiplication of the actual current at 25°C. This error consists of a slope error and some curvature, mostly at the temperature extremes. Figure 5 shows a typical AD590K temperature curve before and after calibration error trimming. Figure 5. Effect to Scale Factor Trim on Accuracy ERROR VERSUS TEMPERATURE: NO USER TRIMS Using the AD590 by simply measuring the current, the total error is the “variance from PTAT” described above plus the effect of the calibration error over temperature. For example the AD590L maximum total error varies from 2.33°C at –55°C to 3.02°C at 150°C. For simplicity, only the large figure is shown on the specification page. NONLINEARITY Nonlinearity as it applies to the AD590 is the maximum deviation of current over temperature from a best-fit straight line. The nonlinearity of the AD590 over the –55°C to +150°C range is superior to all conventional electrical temperature sensors such as thermocouples. RTDs and thermistors. Figure 6 shows the nonlinearity of the typical AD590K from Figure 5. Figure 6. Nonlinearity Figure 7A shows a circuit in which the nonlinearity is the major contributor to error over temperature. The circuit is trimmed by adjusting R1 for a 0 V output with the AD590 at 0°C. R2 is then adjusted for 10 V out with the sensor at 100°C. Other pairs of temperatures may be used with this procedure as long as they are measured accurately by a reference sensor. Note that for +15 V output (150°C) the V+ of the op amp must be greater than 17 V. Also note that V– should be at least –4 V: if V– is ground there is no voltage applied across the device. Understanding the Specifications–AD590 REV. B –5–