MAX5487 MAXIM [Maxim Integrated Products], MAX5487 Datasheet - Page 11

• Manufacturer Part Number: MAX5487
• Description: Dual, 256-Tap, Nonvolatile, SPI-Interface, Linear-Taper Digital Potentiometers
• Manufacturer: MAXIM [Maxim Integrated Products]

Figure 4. Positive LCD-Bias Control Using a Voltage-Divider
Figure 5. Positive LCD-Bias Control Using a Variable Resistor
Figure 6. Programmable Filter
R
WHERE R
AND D = DECIMAL VALUE OF WIPER CODE
V
2
, R
IN
3
= R
MAX5487
MAX5488
MAX5489
MAX5487
MAX5488
MAX5489
HL
HL
HA
= END-TO-END RESISTANCE
x D / 256
Dual, 256-Tap, Nonvolatile, SPI-Interface,
1/2 MAX5487
1/2 MAX5488
1/2 MAX5489
1/2 MAX5487
1/2 MAX5488
1/2 MAX5489
R
______________________________________________________________________________________
3
H_
L_
WA
5V
5V
H_
L_
LA
W_
W_
Linear-Taper Digital Potentiometers
C
R
2
MAX480
MAX480
30V
LB
30V
HB
MAX410
WB
V+
V-
R
1
V
V
OUT
OUT
V
OUT
Use the following equations to calculate the gain (A)
and the -3dB cutoff frequency (f
Figure 7 shows the MAX5487/MAX5488/MAX5489 used
as the feedback resistors in multiple adjustable volt-
age-reference applications. Independently adjust the
output voltages of the MAX6160s from 1.23V to V
0.2V by changing the wiper positions of the MAX5487/
MAX5488/MAX5489.
Connect the high and low terminals of one potentiome-
ter of a MAX5487/MAX5488/MAX5489 to the NULL
inputs of a MAX410, and connect the wiper to the op
amp’s positive supply to nullify the offset voltage over
the operating temperature range. Install the other
potentiometer in the feedback path to adjust the gain of
the MAX410 (see Figure 8).
TRANSISTOR COUNT: 12,177
PROCESS: BiCMOS
Offset Voltage and Gain Adjustment
Adjustable Voltage Reference
f
C
=
A
2
= +
π
1
×
Chip Information
R
1
R
R
3
C
1
2
×
):
C
IN
11
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