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ManualsBrandsAnalog Devices ManualsAnalogTemperature Sensor TO-52

PIN DESIGNATIONS

REV. B

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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 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 compo-

nents, 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 conjunc-

tion 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 require-

ments 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, sup-

ply 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

Summary of content (12 pages)

PAGE 1
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 Calibration Accuracy (AD590M) Excellent Linearity: 60.
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AD590–SPECIFICATIONS (@ +258C and V = +5 V unless otherwise noted) S Model Min ABSOLUTE MAXIMUM RATINGS Forward Voltage ( E+ or E–) Reverse Voltage (E+ to E–) Breakdown Voltage (Case E+ or E–) Rated Performance Temperature Range1 Storage Temperature Range1 Lead Temperature (Soldering, 10 sec) AD590J Typ Max +44 –20 ± 200 +150 +155 +300 –55 –65 POWER SUPPLY Operating Voltage Range +4 OUTPUT Nominal Current Output @ +25°C (298.
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AD590 Model Min ABSOLUTE MAXIMUM RATINGS Forward Voltage ( E+ or E–) Reverse Voltage (E+ to E–) Breakdown Voltage (Case to E+ or E–) Rated Performance Temperature Range1 Storage Temperature Range1 Lead Temperature (Soldering, 10 sec) AD590L Typ Max +44 –20 ± 200 +150 +155 +300 –55 –65 POWER SUPPLY Operating Voltage Range +4 OUTPUT Nominal Current Output @ +25°C (298.
PAGE 4
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.
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Understanding the Specifications–AD590 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.
PAGE 6
AD590 thermal connection. Power source P represents the power dissipated on the chip. The rise of the junction temperature, TJ, above the ambient temperature TA is: T J − T A = P (θ JC + θCA ) Figure 7A. Two Temperature Trim Equation 1 Table I gives the sum of θJC and θCA for several common thermal media for both the “H” and “F” packages. The heatsink used was a common clip-on.
PAGE 7
Applying the AD590 GENERAL APPLICATIONS Figure 12. Differential Measurements Figure 10. Variable Scale Display Figure 10 demonstrates the use of a low cost Digital Panel Meter for the display of temperature on either the Kelvin, Celsius or Fahrenheit scales. For Kelvin temperature Pins 9, 4 and 2 are grounded; and for Fahrenheit temperature Pins 4 and 2 are left open. The above configuration yields a 3 digit display with 1°C or 1°F resolution, in addition to an absolute accuracy of ± 2.
PAGE 8
AD590 Figure 14. 4 mA-to-20 mA Current Transmitter Figure 14 is an example of a current transmitter designed to be used with 40 V, 1 kΩ systems; it uses its full current range of 4 mA-to-20 mA for a narrow span of measured temperatures. In this example the 1 µA/K output of the AD590 is amplified to 1 mA/°C and offset so that 4 mA is equivalent to 17°C and 20 mA is equivalent to 33°C. RT is trimmed for proper reading at an intermediate reference temperature.
PAGE 9
AD590 Figure 18. Matrix Multiplexer CMOS Analog Multiplexers can also be used to switch AD590 current. Due to the AD590’s current mode, the resistance of such switches is unimportant as long as 4 V is maintained across the transducer. Figure 18 shows a circuit which combines the principal demonstrated in Figure 17 with an 8-channel CMOS Multiplexer. The resulting circuit can select one of eighty sensors over only 18 wires with a 7-bit binary word.
PAGE 10
AD590 OUTLINE DIMENSIONS AND PIN DESIGNATIONS Dimensions shown in inches and (mm). FLATPACK PACKAGE: DESIGNATION “F’’ TO-52 Package: Designation “H’’ –10– REV.
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