X9421 Datasheet, PDF (19/21 Pages) Xicor Inc. – Single Digitally Controlled (XDCP) Potentiometer

X9421
APPLICATIONS INFORMATION
Electronic potentiometers provide three powerful application advantages: (1) the variability and reliability of a solid-
state potentiometer, (2) the flexibility of computer-based digital controls, and (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
V_W
V_L
Three terminal Potentiometer;
Variable voltage divider
I
Two terminal Variable Resistor;
Variable current
Basic Circuits
Buffered Reference Voltage
Cascading Techniques
R₁
+V
V_W
+V
+5V
V_W
+ ^OP-07
–
V_OUT = V_W
+V
X
V_W
-5V
+V
V_W
(a)
(b)
Noninverting Amplifier
+5V
V_S
+ ^LM308A
–
V_O
-5V
R₂
R₁
V_O = (1+R₂/R₁)V_S
Voltage Regulator
Offset Voltage Adjustment
V_IN
317
R₁
R₂
V_O (REG) _VS
R₁
100kΩ
–
I_adj
R₂
10kΩ
+
TL072
V_O (REG) = 1.25V (1+R₂/R₁)+I_adj R₂
10kΩ
10kΩ
+12V
-12V
Comparator with Hysterisis
V_S
–
V_O
+
V_O
R₁ R₂
V_UL = {R₁/CR₁+R₂} V_O(max)
V_LL = {R₁/CR₁+R₂} V_O(min)
19
FN8196.1
September 23, 2005