Datasheet

MAX5422/MAX5423/MAX5424
Programmable Filter
Figure 5 shows the configuration for a 1st-order pro-
grammable filter. The gain of the filter is adjusted by
R2, and the cutoff frequency is adjusted by R3. Use the
following equations to calculate the DC gain (G) and
the 3dB cutoff frequency (f
C
):
Adjustable Voltage Reference
Figure 6 shows the MAX5422/MAX5423/MAX5424 used
as the feedback resistors in an adjustable voltage-ref-
erence application. Independently adjust the output
voltage of the MAX6160 from 1.23V to V
IN
- 0.2V by
changing the wiper position of the MAX5422/
MAX5423/MAX5424.
Offset Voltage and Gain Adjustment
Connect the high and low terminals of one potentiome-
ter of a MAX5422/MAX5423/MAX5424 between the
NULL inputs of a MAX410 and the wiper to the op
amp’s positive supply to nullify the offset voltage over
the operating temperature range. Install another
MAX5422/MAX5423/MAX5424 potentiometer in the
feedback path to adjust the gain of the MAX410 (see
Figure 7).
G
R
R
f
RC
C
=+
=
π× ×
1
1
2
1
23
256-Tap, Nonvolatile, SPI-Interface,
Digital Potentiometers
10 ______________________________________________________________________________________
V
OUT
R1
W
H
L
W
H
L
MAX5422
MAX5423
MAX5424
R2
R3
V
IN
C
Figure 5. Programmable Filter
W
H
L
MAX6160
MAX5422
MAX5423
MAX5424
+5V
GND
V
IN
OUT
ADJ
V
0
REF
V
0
= 1.23V
200kΩ
FOR THE MAX5424
R
2
(kΩ)
V
0
= 1.23V
100kΩ
FOR THE MAX5423
R
2
(kΩ)
V
0
= 1.23V
50kΩ
FOR THE MAX5422
R
2
(kΩ)
Figure 6. Adjustable Voltage Reference
6
8
1
7
2
3
5V
-5V
MAX5422
MAX410
4
Figure 7. Offset Voltage Adjustment Circuit
Chip Information
TRANSISTOR COUNT: 10,191
PROCESS: BiCMOS