MAX5432 MAXIM [Maxim Integrated Products], MAX5432 Datasheet - Page 12

• Manufacturer Part Number: MAX5432
• Description: 32-Tap, Nonvolatile, I2C, Linear, Digital Potentiometers
• Manufacturer: MAXIM [Maxim Integrated Products]

32-Tap, Nonvolatile, I
Potentiometers
Figure 9. Positive LCD Bias Control Using a Voltage-Divider
Use the MAX5432–MAX5435 in applications requiring
digitally controlled adjustable resistance, such as LCD
contrast control (where voltage biasing adjusts the dis-
play contrast), or for programmable filters with
adjustable gain and/or cutoff frequency.
Figures 9 and 10 show an application where the volt-
age-divider or variable resistor is used to make an
adjustable, positive LCD bias voltage. The op-amp pro-
vides buffering and gain to the resistor-divider network
made by the potentiometer (Figure 9) or to a fixed
resistor and a variable resistor (Figure 10).
Figure 11 shows the configuration for a 1st-order pro-
grammable filter. The gain of the filter is adjusted by
12
Figure 11. Programmable Filter
______________________________________________________________________________________
MAX5432
MAX5433
V
IN
MAX5432–
MAX5435
H
Applications Information
R3
W
5V
H
L
Positive LCD Bias Control
L
W
R2
C
H
L
Programmable Filter
30V
W
R1
V
V
OUT
OUT
2
C, Linear, Digital
R2, and the cutoff frequency is adjusted by R3. Use the
following equations to calculate the gain (G) and the
3dB cutoff frequency (f
Figure 12 shows the MAX5432/MAX5433 used as the
feedback resistors in an adjustable voltage reference
application. Independently adjust the output voltages of
the MAX6160 from 1.23V to (V
the wiper position of the MAX5432/MAX5433.
Figure 10. Positive LCD Bias Control Using a Variable Resistor
Figure 12. Adjustable Voltage Reference
MAX5432–
MAX5435
V
V
0
0
= 1.23V
= 1.23V
MAX6160
Adjustable Voltage Reference
GND
+5V
V
100kΩ
R
H
L
R
IN
50kΩ
5V
2
2
G
f
(kΩ)
(kΩ)
C
OUT
ADJ
C
=
FOR THE MAX5432
FOR THE MAX5433
=
).
W
1
W
2
+
π
R
R
1
2
×
R
R
IN
H
L
1
2
V
R
1
0
30V
- 0.2V) by changing
3
REF
×
MAX5432
MAX5433
C
V
OUT