X9313
Applications Information
Electronic digitally controlled potentiometers (XDCP) provide
three powerful application advantages:
1. The variability and reliability of a solid-state potentiometer.
2. The flexibility of computer-based digital controls.
3. The retentivity of nonvolatile memory used for the storage
of multiple potentiometer settings or data.
Basic Configurations of Electronic Potentiometers
V
R
V
R
V
H
L
V
/R
W
W
V
I
THREE-TERMINAL POTENTIOMETER;
VARIABLE VOLTAGE DIVIDER
TWO-TERMINAL VARIABLE RESISTOR;
VARIABLE CURRENT
Basic Circuits
BUFFERED REFERENCE VOLTAGE
CASCADING TECHNIQUES
NONINVERTING AMPLIFIER
R
+V
+V
+5V
1
LM308A
V
+V
+
–
S
+5V
V
O
VW
OP-07
+
–
V
X
REF
-5V
VW/RW
V
OUT
R
2
+V
-5V
R
1
V
W
V
= V /R
W W
OUT
(a)
(b)
V
= (1 + R /R )V
2 1 S
O
VOLTAGE REGULATOR
OFFSET VOLTAGE ADJUSTMENT
COMPARATOR WITH HYSTERESIS
R
R
2
1
LT311A
–
V
S
V
S
V
V
(REG)
V
O
317
IN
O
+
100k
R
1
–
+
V
O
TL072
I
adj
R
R
2
1
10k
10k
R
2
10k
V
V
= [R /(R + R )] V (max)
1 1 2 O
UL
LL
= [R /(R + R )] V (min)
1
1
2
O
V
(REG) = 1.25V (1 + R /R ) + I R
ADJ 2
O
2
1
+12V
-12V
(FOR ADDITIONAL CIRCUITS SEE AN115)
FN8177 Rev 7.00
October 7, 2015
Page 8 of 12
RENESAS [ RENESAS TECHNOLOGY CORP ]
