FIGURE 22. DISPLAY BUFFERING FOR INCREASED DRIVE CURRENT
Typical Applications
(Continued)
28
40
39
38
37
36
35
34
33
32
31
30
29
27
26
25
24
23
22
21
OSC 1
OSC 2
OSC 3
TEST
REF HI
REF LO
C
REF
C
REF
COMMON
IN HI
IN LO
A-Z
BUFF
INT
V-
G2
C3
A3
G3
BP
100pF
TO PIN 1
0.1µF
100kΩ
1kΩ 22kΩ
47kΩ
0.22µF
0.47µF
TO BACKPLANE
TO DISPLAY
Test is used as a common-mode reference level to ensure compatibility with most op amps.
10µF
9V
10µF
470kΩ
1µF
4.3kΩ
100pF
(FOR OPTIMUM BANDWIDTH)
1µF
10kΩ
10kΩ
1N914
1µF
0.22µF
5µF
CA3140
2.2MΩ
+
-
100kΩ
AC IN
SCALE FACTOR ADJUST
(V
REF
= 100mV FOR AC TO RMS)
+
-
ICL7107
130Ω
130Ω
130Ω
LED
SEGMENTS
+5V
DM7407
FIGURE 21. AC TO DC CONVERTER WITH WS7106
