X9015_15 Datasheet, PDF (9/12 Pages) Intersil Corporation – Single Digitally Controlled

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
100k
10k
R₂
–
+
TL072
10k
10k
+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
FN8157.6
August 14, 2015