AD590

NS DESIG R NEW T O M EN DED F PLACE M M EN ED RE 88-INTERSIL R EC O EN D N OT C O MM ns 1 - 8 NO RE l Applicatio intersil.com ra nt pp@ Call Ce email: centa or TM AD590 2-Wire, Current Output Temperature Transducer January 2002 Features • Linear Current Output . . . . . . . . . . . . . . . . . . . . 1µA/oK • Wide Temperature Range . . . . . . . . . . . -55oC to 150oC • Two-Terminal Device Voltage In/Current Out • Wide Power Supply Range . . . . . . . . . . . . . +4V to +30V • Sensor Isolation From Case • Low Cost Description The AD590 is an integrated-circuit temperature transducer which produces an output current proportional to absolute temperature. The device acts as a high impedance constant current regulator, passing 1µA/oK for supply voltages between +4V and +30V. Laser trimming of the chip's thin film resistors is used to calibrate the device to 298.2µA output at 298.2oK (25oC). The AD590 should be used in any temperature-sensing application between -55oC to 150oC 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 the simplest application, a resistor, a power source and any voltmeter can be used to measure temperature. In addition to temperature measurement, applications include temperature compensation or correction of discrete components, and biasing proportional to absolute temperature. 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. Ordering Information NONLINEARITY TEMP. RANGE PART (oC) NUMBER (oC) AD590JH ±1.5 -55× to 150× PKG. NO. T3.A PACKAGE 3 Ld Metal Can (TO-52) Pinout AD590 (METAL CAN) Functional Diagram + R1 260Ω + Q2 Q6 C1 26pF R2 1040Ω Q5 Q3 Q4 1 3 CASE Q1 Q7 Q12 Q8 - 2 CHIP SUBSTRATE R3 5kΩ Q10 1 R6 820Ω R5 146Ω R4 11kΩ Q9 8 Q11 1 - CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Intersil and Design is a trademark of Intersil Americas Inc. Copyright © Intersil Americas Inc. 2001, All Rights Reserved 1 File Number 3171.3 AD590 Absolute Maximum Ratings TA = 25oC Supply Forward Voltage (V+ to V-). . . . . . . . . . . . . . . . . . . . . . +44V Supply Reverse Voltage (V+ to V-) . . . . . . . . . . . . . . . . . . . . . .-20V Breakdown Voltage (Case to V+ to V-) . . . . . . . . . . . . . . . . . ±200V Rated Performance Temperature Range TO-52 . -55×oC to 150×oC Thermal Information Thermal Resistance (Typical, Note 1) θJA ( oC/W) θJC (oC/W) Metal Can Package . . . . . . . . . . . . . . . 200 120 Maximum Junction Temperature (Metal Can Package) . . . . . . . 175oC Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC Maximum Lead Temperature (Soldering 10s). . . . . . . . . . . . . 300oC Operating Conditions Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . -55oC to 150oC CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. NOTE: 1. θJA is measured with the component mounted on an evaluation PC board in free air. Electrical Specifications PARAMETER Typical Values at TA = 25οC, V+ = 5V, Unless Otherwise Specified TEST CONDITIONS AD590I 298.2 1.0 Notes 1, 5 -55×oC to 150×oC, Note 7 ±20.0 Max ±5.8 Max Note 6 Notes 2, 6 Notes 3, 6 ±3.0 Max ±0.1 Max ±0.1 Max 40 ±10.0 Max ±3.0 Max ±1.5 Max ±0.1 Max ±0.1 Max 40 oC oC oC oC oC/Month AD590J 298.2 1.0 ±5.0 Max UNITS µA µA/oK oC Nominal Output Current at 25oC (298.2oK) Nominal Temperature Coefficient Calibration Error at 25oC Absolute Error Without External Calibration Adjustment With External Calibration Adjustment Non-Linearity Repeatability Long Term Drift Current Noise Power Supply Rejection +4V < V+ < +5V +5V < V+ < +15V +15V < V+ < +30V Case Isolation to Either Lead Effective Shunt Capacitance Electrical Turn-On Time Reverse Bias Leakage Current Power Supply Range NOTES: 2. Does not include self heating effects. Note 1 Note 4 ±10.0 Max pA /√Hz 0.5 0.2 0.1 1010 100 20 10 +4 to +30 0.5 0.2 0.1 1010 100 20 10 +4 to +30 µA/V µA/V µA/V Ω pF µs pA V 3. Maximum deviation between 25oC reading after temperature cycling between -55oC and 150oC. 4. Conditions constant +5V, constant 125oC. 5. Leakage current doubles every 10oC. 6. Mechanical strain on package may disturb calibration of device. 7. Guaranteed but not tested. 8. -55oC Guaranteed by testing at 25oC and 150oC. 2 AD590 Trimming Out Errors The ideal graph of current versus temperature for the AD590 is a straight line, but as Figure 1 shows, the actual shape is slightly different. Since the sensor is limited to the range of -55oC to 150oC, it is possible to optimize the accuracy by trimming. Trimming also permits extracting maximum performance from the lower-cost sensors. The circuit of Figure 2 trims the slope of the AD590 output. The effect of this is shown in Figure 3. The circuit of Figure 4 trims both the slope and the offset. This is shown in Figure 5. The diagrams are exaggerated to show effects, but it should be clear that these trims can be used to minimize errors over the whole range, or over any selected part of the range. In fact, it is possible to adjust the I-grade device to give less than 0.1oC error over the range 0oC to 90oC and less than 0.05oC error from 25oC to 60oC. IDEAL 35.7k Ω R1 2kΩ + AD590 VOUT = 100mV/ oC +10V 97.6kΩ R2 5 kΩ VR 1 = OFFSET R 2 = SLOPE FIGURE 4. SLOPE AND OFFSET TRIMMING I (µA) ACTUAL (GREATLY EXAGGERATED) FIGURE 5A. UNTRIMMED T (oK) FIGURE 1. TRIMMING OUT ERRORS +5V + + AD590 + R 100 Ω 950Ω VOUT = 1mV/ oK R = SLOPE FIGURE 5B. TRIM ONE: OFFSET FIGURE 2. SLOPE TRIMMING IDEAL ACTUAL I (µA) TRIMMED T (oK) FIGURE 5C. TRIM TWO: SLOPE FIGURE 3. EFFECT OF SLOPE TRIM 3 AD590 Accuracy Maximum errors over limited temperature spans, with VS = +5V, are listed by device grade in the following tables. The tables reflect the worst-case linearities, which invariably occur at the extremities of the specified temperature range. The trimming conditions for the data in the tables are shown in Figure 2 and Figure 4. All errors listed in the tables are ±oC. For example, if ±1oC maximum error is required over the 25oC to 75oC range (i.e., lowest temperature of 25oC and span of 50oC), then the trimming of a J-grade device, using the single-trim circuit (Figure 2), will result in output having the required accuracy over the stated range. An I-grade device with two trims (Figure 4) will have less than ±0.2oC error. If the requirement is for less than ±1.4oC maximum error, from -25oC to 75oC (100oC span from -25oC), it can be satisfied by an I-grade device with two trims. FIGURE 5D. TRIM THREE: OFFSET AGAIN FIGURE 5. EFFECT OF SLOPE AND OFFSET TRIMMING I Grade Maximum Errors (oC) LOWEST TEMPERATURE IN SPAN (×oC) NUMBER OF TRIMS None None None None None None One One One One One One Two Two Two Two Two Two NOTE: 9. Less than ±0.05oC. TEMPERATURE SPAN (oC) 10 25 50 100 150 205 10 25 50 100 150 205 10 25 50 100 150 205 -55 8.4 10.0 13.0 15.2 18.4 20.0 0.6 1.8 3.8 4.8 5.5 5.8 0.3 0.5 1.2 1.8 2.6 3.0 -25 9.2 10.4 13.0 16.0 19.0 0.4 1.2 3.0 4.5 4.8 0.2 0.3 0.6 1.4 2.0 0 10.0 11.0 12.8 16.6 19.2 0.4 1.0 2.0 4.2 5.5 0.1 0.2 0.4 1.0 2.8 25 10.8 11.8 13.8 17.4 0.4 1.0 2.0 4.2 (Note 9) (Note 9) 0.2 2.0 50 11.6 12.0 14.6 18.8 0.4 1.0 2.0 5.0 (Note 9) 0.1 0.2 2.5 75 12.4 13.8 16.4 0.4 1.2 3.0 0.1 0.2 0.3 100 13.2 15.0 18.0 0.4 1.6 3.8 0.2 0.3 0.7 125 14.4 16.0 0.6 1.8 0.3 0.5 - 4 AD590 J Grade Maximum Errors (oC) NUMBER OF TRIMS None None None None None None One One One One One One Two Two Two Two Two Two NOTE: 10. Less than ±0.05oC. TEMPERATURE SPAN (oC) 10 25 50 100 150 205 10 25 50 100 150 205 10 25 50 100 150 205 LOWEST TEMPERATURE IN SPAN (×oC) -55 4.2 5.0 6.5 7.7 9.2 10.0 0.3 0.9 1.9 2.3 2.5 3.0 0.1 0.2 0.4 0.7 1.0 1.6 -25 4.6 5.2 6.5 8.0 9.5 0.2 0.6 1.5 2.2 2.4 (Note 10) 0.1 0.2 0.5 0.7 0 5.0 5.5 6.4 8.3 9.6 0.2 0.5 1.0 2.0 2.5 (Note 10) (Note 10) 0.1 0.3 1.2 25 5.4 5.9 6.9 8.7 0.2 0.5 1.0 2.0 (Note 10) (Note 10) (Note 10) 0.7 50 5.8 6.0 7.3 9.4 0.2 0.5 1.0 2.3 (Note 10) (Note 10) (Note 10) 1.0 75 6.2 6.9 8.2 0.2 0.6 1.5 (Note 10) (Note 10) 0.1 100 6.6 7.5 9.0 0.2 0.8 1.9 (Note 10) 0.1 0.2 125 7.2 8.0 0.3 0.9 0.1 0.2 (Note 10) - NOTES 1. Maximum errors over all ranges are guaranteed based on the known behavior characteristic of the AD590. 2. For one-trim accuracy specifications, the 205oC span is assumed to be trimmed at 25oC; for all other spans, it is assumed that the device is trimmed at the midpoint. 3. For the 205oC span, it is assumed that the two-trim temperatures are in the vicinity of 0oC and 140oC; for all other spans, the specified trims are at the endpoints. 4. In precision applications, the actual errors encountered are usually dependent upon sources of error which are often overlooked in error budgets. These typically include: a. Trim error in the calibration technique used b. Repeatability error c. Long term drift errors Trim Error is usually the largest error source. This error arises from such causes as poor thermal coupling between the device to be calibrated and the reference sensor; reference sensor errors; lack of adequate time for the device being calibrated to settle to the final temperature; radically different thermal resistances between the case and the surroundings (RθCA) when trimming and when applying the device. Repeatability Errors arise from a strain hysteresis of the package. The magnitude of this error is solely a function of the magnitude of the temperature span over which the device is used. For example, thermal shocks between 0oC and 100oC involve extremely low hysteresis and result in repeatability errors of less than ±0.05oC. When the thermalshock excursion is widened to -55oC to 150oC, the device will typIcally exhibit a repeatability error of ±0.05oC (±0.10 guaranteed maximum). Long Term Drift Errors are related to the average operating temperature and the magnitude of the thermal-shocks experienced by the device. Extended use of the AD590 at temperatures above 100oC typically results in long-term drift of ±0.03oC per month; the guaranteed maximum is ±0.10oC per month. Continuous operation at temperatures below 100oC induces no measurable drifts in the device. Besides the effects of operating temperature, the severity of thermal shocks incurred will also affect absolute stability. For thermal-shock excursions less than 100oC, the drift is difficult to measure (