11

LT1002

Precision

±10V Reference

3

LM129A

4

10

11

13

14

0.1%

1k

12

6

7

5

1002 TA08

10k

1%

3.3k

0.1%

10k

–

+

OUT 2

–10.000V

–15V

+15V

OUT 1

10.000V

1

–

+

1

130k

5%

8.2k

1%

1%

3.3k

When the upper or lower limit is exceeded the LED lights

up. Positive feedback to one of the nulling terminals

creates 5 to 20

µV of hysteresis on both amplifiers. This

feedback changes the offset voltage of the LT1002 by less

than 5

µV. Therefore, the basic accuracy of the comparator

is limited only by the low offset voltage of the LT1002.

Dual Limit Microvolt Comparator

4

10

3

11

13

12

5

1

14

6

8

7

UPPER

LIMIT

INPUT

LOWER

LIMIT

1002 TA09

430k

1%

20k

5%

–15V

–15V

+15V

FLV117

39.2

Ω

1%

15k

1%

39.2

Ω

1%

15k

1%

1k

5%

–

+

–

+

1

1

430k

1%

The LT1002 contributes less than 5% of the total drift with

temperature, noise and long term drift of the reference.

The accuracy of the –10V output is limited by the matching

of the two 10k resistors.