max5423eta Maxim Integrated Products, Inc., max5423eta Datasheet - Page 10

• Manufacturer Part Number: max5423eta
• Description: 256-tap, Nonvolatile, Spi-interface, Digital Potentiometers
• Manufacturer: Maxim Integrated Products, Inc.

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
256-Tap, Nonvolatile, SPI-Interface,
Digital Potentiometers
Figure 5. Programmable Filter
Figure 6. Adjustable Voltage Reference
10
______________________________________________________________________________________
MAX5422
MAX5423
MAX5424
MAX5422
MAX5423
MAX5424
V
IN
C
G
f
C
R3
H
L
=
=
V
V
V
0
0
0
1
= 1.23V
= 1.23V
= 1.23V
2
+
π ×
MAX6160
W
R2
C
GND
+5V
H
L
V
R
R
R
100kΩ
200kΩ
):
R
R
IN
50kΩ
2
1
2
2
2
Programmable Filter
(kΩ)
(kΩ)
(kΩ)
R
1
3
OUT
ADJ
FOR THE MAX5422
FOR THE MAX5424
FOR THE MAX5423
W
×
R1
W
C
H
L
V
0
V
REF
OUT
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
changing the wiper position of the MAX5422/
MAX5423/MAX5424.
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).
Figure 7. Offset Voltage Adjustment Circuit
TRANSISTOR COUNT: 10,191
PROCESS: BiCMOS
Offset Voltage and Gain Adjustment
Adjustable Voltage Reference
2
3
7
-5V
5V
MAX410
4
1
8
Chip Information
MAX5422
6
IN
- 0.2V by