Datasheet

MAX5234/MAX5235
Digital Control of Gain and Offset
The two DACs can be used to control the offset and
gain for curve-fitting nonlinear functions, such as trans-
ducer linearization or analog compression/expansion
applications. The input signal is used as the reference
for the gain-adjust DAC, whose output is summed with
the output from the offset-adjust DAC. The relative
weight of each DAC output is adjusted by R1, R2, R3,
and R4 (Figure 11).
Sharing a Common DIN Line
Several MAX5234/MAX5235 may share one common
DIN signal line (Figure 12). In this configuration, the
data bus is common to all devices; data is not shifted
through a daisy-chain. The SCLK and DIN lines are
shared by all devices, but each IC needs its own dedi-
cated CS line.
Power-Supply Considerations
On power-up, the input and DAC registers clear (set to
zero code). Bypass the power supply with a 4.7µF
Single-Supply 3V/5V, Voltage-Output, Dual,
Precision 12-Bit DACs
16 ______________________________________________________________________________________
DAC_
REF_
V
DD
GND
5V/3V
GAIN = 1.6384V/V
MAX5234
MAX5235
OUT_
121kΩ
77.25kΩ
1kΩ
Figure 7. Unipolar Output Circuit (Rail-to-Rail)
DAC_
REF_
V
DD
GND
5V/3V
MAX5234
MAX5235
OUT_
121kΩ
10kΩ 10kΩ
77.25kΩ
1kΩ
V
OUT
V+
0.06384R
V-R
Figure 8. Bipolar Output Circuit
DAC_
REF_
V
DD
GND
5V/3V
5V/3V
500mV
P-P
AC
REFERENCE
INPUT
OUT_
121kΩ
26kΩ
10kΩ
77.25kΩ
1kΩ
MAX495
MAX5234
MAX5235
Figure 9. External Reference with AC Components
DAC_
DIN
MAX5234
MAX5235
REF_
V
DD
V
OUT
GND
5V/3V
OUT_
PHOTODIODE
V+
V+
V-
121kΩ
77.25kΩ
1kΩ
R
PULLDOWN
µP
Figure 10. Digital Calibration