max5235 Maxim Integrated Products, Inc., max5235 Datasheet - Page 16

• Manufacturer Part Number: max5235
• Description: Single-supply 3v/5v, Voltage-output, Dual, Precision 12-bit Dacs
• Manufacturer: Maxim Integrated Products, Inc.

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).
Single-Supply 3V/5V, Voltage-Output, Dual,
Precision 12-Bit DACs
Figure 7. Unipolar Output Circuit (Rail-to-Rail)
Figure 9. External Reference with AC Components
16
REFERENCE
5V/3V
INPUT
500mV
AC
______________________________________________________________________________________
26kΩ
P-P
10kΩ
GAIN = 1.6384V/V
Digital Control of Gain and Offset
REF_
5V/3V
DAC_
MAX5234
MAX5235
MAX495
DAC_
GND
REF_
5V/3V
V
DD
MAX5234
MAX5235
121kΩ
77.25kΩ
1kΩ
V
DD
77.25kΩ
1kΩ
121kΩ
OUT_
GND
OUT_
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.
On power-up, the input and DAC registers clear (set to
zero code). Bypass the power supply with a 4.7µF
Figure 8. Bipolar Output Circuit
Figure 10. Digital Calibration
µP
REF_
DIN
DAC_
GND
MAX5234
MAX5235
REF_
DAC_
MAX5234
MAX5235
Power-Supply Considerations
77.25kΩ
Sharing a Common DIN Line
5V/3V
V
DD
GND
5V/3V
121kΩ
V
OUT_
121kΩ
1kΩ
DD
77.25kΩ
1kΩ
10kΩ
0.06384R
R
OUT_
V+
10kΩ
V+
V-
R
PHOTODIODE
PULLDOWN
V+
V-
V
OUT
V
OUT