X9015 Datasheet, PDF (9/11 Pages) Xicor Inc. – Digitally-Controlled Potentiometer

X9015
Applications Information
Electronic digitally controlled potentiometers provide two powerful application advantages: (1) the variability and reliability of a
solid-state potentiometer, and (2) the flexibility of computer-based digital controls.
Basic Configurations of Electronic Potentiometers
V_R
V_R
V_H/R_H
V_W/R_W
V_L/R_L
Three terminal potentiometer;
variable voltage divider
I
Two terminal variable resistor;
variable current
Basic Circuits
Buffered Reference Voltage
R₁
+V
+5V
V_REF
V_W/R_W
+
–
OP-07
V_OUT
–5V
V_OUT = V_W
Cascading Techniques
+V
+V
X
V_W/R_W
+V
V_W/R_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
I_adj
R₂
V_O (REG) = 1.25V (1+R₂/R₁)+I_adj R₂
V_O (REG)
R₁
V_S
100kΩ
10kΩ
R₂
–
+
TL072
10kΩ
10kΩ
+12V
-12V
Comparator with Hysteresis
V_S ^LT311A –
V_O
+
V_O
R₁ R₂
V_UL = {R₁/(R₁+R₂)} V_O(max)
V_LL = {R₁/(R₁+R₂)} V_O(min)
(for additional circuits see AN115)
9
FN8157.1
September 15, 2005