Detailed Description

The Maxim ICL7116 and ICL7117 3½ digit ADCs are

similar to the Maxim ICL7106 and ICL7107, except for the

addition of a Hold pin. For a detailed product description,

package dimensions, and applications information (other

than the operation of the Hold pin described below) refer

to Maxim’s ICL7106 and ICL7107 data sheet

Hold Input

The Hold input is a digital input with a logic threshold

approximately midway between V+ and Test (ICL7116)

or V+ and Ground (ICL7117). The ICL7116/ICL7117 con-

tinuously performs conversions, independent of the Hold

input. When the Hold input is connected to V+, however,

the display latch pulse is inhibited, and the the display

latches are not updated. The Hold input has a 70kΩ pull-

down resistor to Test (ICL7116) or Ground (ICL7117) and

the Hold input will be pulled low if it is left open. When

Hold is low the ICL7116/ICL7117 updates the display

at the end of each conversion. The Hold input is CMOS

compatible and can also be driven by a switch connected

Unlike the ICL7106 and the ICL7107, the ICL7116 and

ICL7117 do not have a Reference Low input. Apply the

reference voltage between Reference High (REF HI) and

Common.

Figure 1. Maxim ICL7116 Typical Operating Circuit, 200mV Reference

ANALOG

INPUT

ICL7116

+

-

LCD DISPLAY

CLOSED = HOLD

OPEN = RUN

9V

TO ANALOG

COMMON PIN

[PIN 32]

IN HI

31

IN LO

30

32

1MΩ

0.01µF

COMMON

BUFF

28

A-Z

29

INT

29

0.47µF

0.22µF

47kΩ

39

34

33

0.1µF

C+REF C-REF

100pF

100kΩ

40

SEGMENT

DRIVE

2–19

22–25

POL

BP

20

21

MINUS SIGN

BACKPLANE

DRIVE

HOLD 1

REF HI

35

36

26

24kΩ

10kΩ

ICL7116/ICL7117

3½ Digit ADCs with Display Hold

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