Datasheet

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
to V
+
(Figure 1 and Figure 2) or by a PNP transistor.
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
V
REF
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
OSC
2
OSC
3
OSC
1
38
C
OSC
100pF
100kΩ
40
R
OSC
SEGMENT
DRIVE
2–19
22–25
POL
BP
20
21 MINUS SIGN
BACKPLANE
DRIVE
HOLD
1
V
+
V
-
REF HI
35
36
26
24kΩ
10kΩ
Figure 1
ICL7116/ICL7117 3½ Digit ADCs with Display Hold
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