AD590IH View Datasheet(PDF) - Intersil

Part Name

Description

Manufacturer

AD590IH

2-Wire, Current Output Temperature Transducer

Intersil 

AD590

+

AD590

-

10mV/ oC

10kΩ

0.1%

1kΩ

ZERO SET

44.2kΩ

ICL7611

+

-

115kΩ

100Ω

+15V

118kΩ

20kΩ

FULL-SCALE

ADJUST

10kΩ

2.7315V

M +100µA

-

V+

50kΩ

(8V MIN)

V-

+

NO. 1

-

5MΩ

+

741

-

+

NO. 2

- 10kΩ

10kΩ

VOUT = (T2 - T1) x

(10mV/ oC)

FIGURE 15. DIFFERENTIAL THERMOMETER

FIGURE 14. CENTIGRADE THERMOMETER (0oC-100oC)

The ultra-low bias current of the ICL7611 allows the use of

large value gain resistors, keeping meter current error under

1/2%, and therefore saving the expense of an extra meter

driving amplifier. See Figure 14.

The 50kΩ pot trims offsets in the devices whether internal or

external, so it can be used to set the size of the difference

interval. this also makes it useful for liquid level detection

(where there will be a measurable temperature difference).

See Figure 15.

The reference junction(s) should be in close thermal contact

with the AD590 case. V+ must be at least 4V, while ICL8069

current should be set at 1mA - 2mA. Calibration does not

require shorting or removal of the thermocouple: set R1 for

V2 = 10.98mV. If very precise measurements are needed,

adjust R2 to the exact Seebeck coefficient for the thermo-

couple used (measured or from table) note V1, and set R1 to

buck out this voltage (i.e., set V2 = V1). For other thermocou-

ple types, adjust values to the appropriate Seebeck

coefficient. See Figure 16.

V+

+

1µA/ oK

-

R2 40.2Ω

SEEBECK

- COEFFICIENT = 40µV/oK

TC = 40µV/oK V1 = 10.98mV

+

TYPE K

V+

+

VOUT

-

1.235V

V2 = 10.98mV

40.2Ω

R1 4521Ω

ICL8069

4.7µF

FIGURE 16. COLD JUNCTION COMPENSATION FOR TYPE K THERMOCOUPLE

12-10

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