AD590

Rev. C | Page 12 of 16

The inhibit input on the multiplexer turns all sensors off for

minimum dissipation while idling.

Figure 23 demonstrates a method of multiplexing the AD590 in

the two-trim mode (see Figure 10 and Figure 11). Additional

AD590s and their associated resistors can be added to multiplex

up to eight channels of ±0.5°C absolute accuracy over the

temperature range of −55°C to +125°C. The high temperature

restriction of 125°C is due to the output range of the op amps;

output to 150°C can be achieved by using a 20 V supply for the

op amp.

4028

CMOS

BCD-TO-

DECIMAL

DECODER

11

9

10

11

6

16

10V

3

14

2

AD590

1

0

2

10k

Ω 10mV/°C

4051 CMOS ANALOG

MULTIPLEXER

–

+

22

–

+

12

–

+

02

–

+

21

–

+

11

–

+

01

–

+

20

–

+

10

–

+

00

8

12

ROW

SELECT

COLUMN

SELECT

INHIBIT

78

13

10

0

13

1

14

2

15

BINARY TO 1-OF-8 DECODER

LOGIC

LEVEL

INTERFACE

10V

16

Figure 22. Matrix Multiplexer

–

+

AD590L

–

+

AD590L

DECODER/

DRIVER

S1

S2

S8

AD7501

–15V

2k

Ω

35.7k

Ω

5k

Ω

97.6k

Ω

2k

Ω

35.7k

Ω

5k

Ω

97.6k

Ω

+15V

TTL/DTL TO CMOS

INTERFACE

BINARY

CHANNEL

SELECT

EN

–15V

27k

Ω

10mV/°C

V+

AD707A

+15V

AD581

–

+

–5V TO –15V

Figure 23. 8-Channel Multiplexer