CAT5119 CATALYST [Catalyst Semiconductor], CAT5119 Datasheet - Page 6

• Manufacturer Part Number: CAT5119
• Description: 32-Tap MiniPot TM Digitally Programmable Potentiometers with 2-Wire Interface
• Manufacturer: CATALYST [Catalyst Semiconductor]

CAT5110, CAT5118, CAT5119, CAT5123, CAT5124, CAT5125
Doc. No. 220, Rev. E
APPlICATIOns InFOrMATIOn
The MiniPots are intended for circuits requiring digitally
controlled adjustable resistance, such as LCD contrast
control, where voltage biasing adjusts the display
contrast.
AlTernATIVe POsITIVe lCD bIAs COnTrOl
An op amp can be used to provide buffering and gain on
the output of the CAT50/CAT525. This can be done
by connecting the wiper output to the positive input of
a noninverting op amp as shown in Figure 3. Figure 4
shows a similar circuit for the CAT59/CAT524.
Figure 3. Positive lCD bias Control
Figure 5a. Adjustable Gain Circuit
CAT5110/CAT5125
CAT5118/CAT5123
+5V
L
H
V
IN
W
H
L
V
CC
30V
V
OUT
V
OUT
6
ADjusTAble GAIn
Figure 5 shows how to use either a variable resistor or a
potentiometer to digitally adjust the gain of a noninverting
op amp configuration, by connecting the Minipot in
series with a resistor to ground. The MiniPots have a low
5ppm/ºC ratiometric tempco that allows for a very stable
adjustable gain configuration over temperature.
Figure 4. Positive lCD bias Control
Figure 5b. Adjustable Gain Circuit
CAT5119/CAT5124
L
V
CAT5110/CAT5125
+5V
IN
H
L
W
Characteristics subject to change without notice
H
© 2007 by Catalyst Semiconductor, Inc.
V
CC
30V
V
OUT
V
OUT