AD538
V
IN
1V
V
= 1V
O
OPTIONAL
ABSOLUTE VALUE SECTION
5kΩ
I
10kΩ
Z
Z
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
A
D
20kΩ
LOG
V
25kΩ
IN4148 IN4148
RATIO
R
100Ω
B
+V
7
S
*
B
+10V
+2V
I
X
V
20kΩ
OS
V
X
1
20kΩ
2
V
8
6
25kΩ
IN
100Ω
100Ω
SIGNAL
GND
3
+2V
4
S
AD OP-07
OR AD811
PWR
GND
INTERNAL
VOLTAGE
(V TAP
OS
TO –V
–V
+15V
–15V
)
REFERENCE
AD538
S
C
OUTPUT
25kΩ
I
V
O
Y
V
O
ANTILOG
D1
IN4148
V
I
Y
LOG
1kΩ
25kΩ
100Ω
SCALE FACTOR
TRIM
R
100Ω
C
1kΩ
*
*
RATIO MATCH 1% METAL FILM
RESISTORS FOR BEST ACCURACY
Figure 17. Square Root Circuit
Rev. E | Page 14 of 16
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