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

Two-Terminal IC

a

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 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.

REV. B

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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.

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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

Ω

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.

–2–

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

Ω

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

REV. B

–3–

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.

–4–

Figure 1. Schematic Diagram

Figure 2. V–I Plot

REV. B