Datasheet

Adjustable Voltage Reference
In Figure 7a, the MAX5403/MAX5404/MAX5405 is
shown with the MAX6160 to make an adjustable volt-
age reference. In this circuit, the H
X
pin of the
MAX5403/MAX5404/MAX5405 is connected to the OUT
pin of the MAX6160, the L
X
pin of the MAX5403/
MAX5404/MAX5405 is connected to GND, and the W
X
pin of the MAX5403/MAX5404/MAX5405 is connected
to the ADJ pin of the MAX6160. The MAX5403/
MAX5404/MAX5405 allow precise setting of the voltage
reference output. A low 5ppm/°C ratiometric tempco
allows a very stable, adjustable voltage over tempera-
ture.
MAX5403/MAX5404/MAX5405
Dual 256-Tap, Low-Drift,
Digital Potentiometers in 10-µMAX
_______________________________________________________________________________________ 9
ADDRESS DATA WOR
D
B0 (A0) B1 (D7) B2 (D6) B3 (D5) B4 (D4) B5 (D3) B6 (D2) B7 (D1) B8 (D0)
(MSB) (LSB)
First Bit In Last Bit In
Figure 4. Serial Data Format
Figure 5. I to V Converter
V
0
/ I
S
= R
3
(1 + R
2
/R
1
) + R
2
+5V
R3
R1
R2
V
0
L
A
W
A
MAX4250
MAX5403
MAX5404
MAX5405
Figure 6a. Adjustable Gain Circuit Using: 2-Terminal Variable
Resistor
V
CC
W
A
V
OUT
MAX5403
MAX5404
MAX5405
L
A
Figure 7a. Adjustable Voltage Reference Using: 3-Terminal
Potentiometer
V
O
REF = 12.3kV
✕
Ω / (100kΩ
✕
C / 255) for MAX5403
V
O
REF = 61.5kV
✕
Ω / (50kΩ
✕
C / 255) for MAX5404
V
O
REF = 123kV
✕
Ω / (100kΩ
✕
C / 255) for MAX5405
WHERE C IS ANY CODE BEING WRITTEN TO A DEVICE.
MAX6160
OUT
ADJ
GND
VIN
+5V
V
O
REF
W
B
L
B
H
B
Figure 6b. Adjustable Gain Circuit Using: 3-Terminal
Potentiometer
V
CC
V
IN
L
B
H
B
W
B
V
OUT
MAX5403
MAX5404
MAX5405