Analog Devices AD590, AD590MH, AD590LH, AD590LF, AD590KH Datasheet

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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 CalibrationAccuracy(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 applica-
tion 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.
Temperature Transducer
AD590
PIN DESIGNATIONS
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 M) 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.
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Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 617/329-4700 World Wide Web Site: http://www.analog.com Fax: 617/326-8703 © Analog Devices, Inc., 1997
AD590–SPECIFICA TIONS
(@ +258C and VS = +5 V unless otherwise noted)
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 Range Storage Temperature Range
1
1
–55 +150 –55 +150 °C –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 Repeatability Long-Term Drift
2
3
±0.1 ±0.1 °C ±0.1 ±0.1 °C
Current Noise 40 40 pA/ Power Supply Rejection
+4 V V +5 V V +15 V V
Case Isolation to Either Lead 10
+5 V 0.5 0.5 µA/V
S
+15 V 0.2 0.2 µV/V
S
+30 V 0.1 0.1 µA/V
S
10
10
10
Effective Shunt Capacitance 100 100 pF Electrical Turn-On Time 20 20 µs Reverse Bias Leakage Current
4
(Reverse Voltage = 10 V) 10 10 pA
Hz
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.
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REV. B
AD590
Model AD590L AD590M
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 to E+ or E–) ±200 ±200 Volts Rated Performance Temperature Range Storage Temperature Range
1
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 61.0 60.5 °C Absolute Error (Over Rated Performance Temperature Range)
Without External Calibration Adjustment 63.0 61.7 °C With ±25°C Calibration Error Set to Zero 61.6 61.0 °C Nonlinearity 60.4 60.3 °C Repeatability Long-Term Drift
2
3
Current Noise 40 40 pA/ Power Supply Rejection
+4 V V +5 V V +15 V V
+5 V 0.5 0.5 µA/V
S
+15 V 0.2 0.2 µA/V
S
+30 V 0.1 0.1 µA/V
S
Case Isolation to Either Lead 10 Effective Shunt Capacitance 100 100 pF Electrical Turn-On Time 20 20 µs Reverse Bias Leakage Current
4
(Reverse Voltage = 10 V) 10 10 pA
1
–55 +150 –55 +150 °C –65 +155 –65 +155 °C
±0.1 ±0.1 °C ±0.1 ±0.1 °C
10
10
10
Hz
PACKAGE OPTIONS
TO-52 (H-03A) AD590LH AD590MH Flatpack (F-2A) AD590LF AD590MF
TEMPERATURE SCALE CONVERSION EQUATIONS
5
°C =
°F =
(°F –32) K C+273.15
9 9
°C + 32 °R F+459.7
5
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AD590
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
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.
CIRCUIT DESCRIPTION
1
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.
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Figure 1. Schematic Diagram
Figure 2. V–I Plot
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