Datasheet

AD737 Data Sheet
Rev. I | Page 16 of 24
COM
+V
AD589
1.23V
C
AV
C
C
POWER
DOWN
0.1µF
C
C
10µF
SWITCH CLOSED
ACTIVATES
POWER-DOWN
MODE. AD737 DRAWS
JUST 40µA IN THIS MODE
2V
20V
200V
9MΩ
900kΩ
90kΩ
10kΩ
V
IN
200mV
V
IN
–V
S
+
+
+V
S
+
1µF
OUTPUT
1MΩ
–V
S
+V
S
1N4148
1N4148
47kΩ
1W
1µF
+
COMMON
33µF
REF LOW
REF HIGH
3
1
/ 2 DIGIT ICL7136
TYPE CONVERTER
LOW
HIGH
ANALOG
9V
200kΩ
20kΩ
50kΩ
+
1PRV
0.01µF
RMS
CORE
AD737
BIAS
SECTION
INPUT
AMPLIFIER
8kΩ
8kΩ
1
2
3
4
8
7
6
5
00828-027
FULL-WAVE
RECTIFIER
Figure 27. 3½ Digit DVM Circuit
COM
INPUT
C
AV
C
AV
33µF
C
F
0.47µF
C1
0.47µF
C5
1µF
C4
2.2µF
R7
100kΩ
R4
5kΩ
R2
5kΩ
R3
78.7kΩ
R5
80.6kΩ
R1
69.8kΩ
1%
R8
100kΩ
C3
0.01µF
0.01µF
C2
0.01µF
C
C
POWER
DOWN
INPUT SCALE FACTOR ADJ
V
IN
–V
S
OUTPUT
+V
S
+
OUTPUT
AD737
+
5V
5V
2.5V
AD8541AR
5V
NC
NC = NO CONNECT
OUTPUT ZERO
ADJUST
1
2
3
4
8
7
6
5
1
4
7
5
3
6
2
00828-028
Figure 28. Battery-Powered Operation for 200 mV Maximum RMS Full-Scale Input
V
OUT
RMS
CORE
C
C
V
IN
C
F
10µF
00828-029
COM
OUTPUT
AD737
BIAS
SECTION
INPUT
AMPLIFIER
SCALE FACTOR
ADJUST
8kΩ
8kΩ
POWER
DOWN
–V
S
+V
S
+
C
AV
1
2
3
4
8
7
6
5
100Ω
200Ω
C
AV
33µF
C
C
10µF
+
+
FULL-WAVE
RECTIFIER
Figure 29. External Scale Factor Trim