TC7126
TC7126A
Simple Inverter for Fixed Decimal Point
or Display Annunciator
V+
V+
TC7126A
BP 21
TEST 37
4049
GND
TO LCD
DECIMAL
POINT
TO
BACKPLANE
Multiple Decimal Point or
Annunciator Driver
V+
V+ BP
TC7126A
DECIMAL
POINT
SELECT
TO LCD
DECIMAL
POINTS
3-1/2 DIGIT
ANALOG-TO-DIGITAL CONVERTERS
RSTANDARD
RUNKNOWN
VR+EF V+
VR–EF
VI+N
TC7126A
VI–N
ANALOG
COMMON
LCD
Figure 10. Low Parts Count Ratiometric Resistance Measurement
TEST
4030
GND
Figure 9. Decimal Point and Annunciator Drives
VIN
9 MΩ
900 kΩ
90 kΩ
1N4148
200 mV
C1
0.02
µF
2V
C2
47 kΩ
1W
20V
10%
200V
1 MΩ
+
1 µF
1
2
10 MΩ
3
4
6.8 µF +
5
6
7
20 kΩ
10%
10 kΩ
COM
C1 = 3 pF TO 10 pF, VARIABLE
C2 = 132 pF, VARIABLE
AD636
9V
26
14
1 V+ V–
27
13
240 kΩ
29
12
TC7126A
11
10 kΩ
10
36
V
+
REF
35
V
–
REF
28
9
8
2.2
µF
1 MΩ 10%
32 ANALOG
COMMON
31
0.01
V
+
IN
µF
30
V
+
OUT
40
38
26 V –
39
BP
SEGMENT
DRIVE
3-228
Figure 11. 3-1/2 Digit True RMS AC DMM
LCD
TELCOM SEMICONDUCTOR, INC.