MAX525 Maxim, MAX525 Datasheet - Page 13

• Manufacturer Part Number: MAX525
• Description: Low-Power / Quad / 12-Bit Voltage-Output DAC with Serial Interface
• Manufacturer: Maxim

For a unipolar output, the output voltages and the refer-
ence inputs have the same polarity. Figure 9 shows the
MAX525 unipolar output circuit, which is also the typi-
cal operating circuit. Table 2 lists the unipolar output
codes.
For rail-to-rail outputs, see Figure 10. This circuit shows
the MAX525 with the output amplifiers configured with a
closed-loop gain of +2 to provide 0V to 5V full-scale
range when a 2.5V reference is used.
Table 2. Unipolar Code Table
Table 3. Bipolar Code Table
Note: 1LSB = (V
__________Applications Information
1 1 1 1
1 0 0 0
0 1 1 1
0 0 0 0
0 0 0 0
1 1 1 1
1 0 0 0
0 1 1 1
0 0 0 0
0 0 0 0
1000
1000
MSB
MSB
DAC CONTENTS
DAC CONTENTS
Low-Power, Quad, 12-Bit Voltage-Output DAC
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 0
0 0 0 0
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 0
0 0 0 0
0000
0000
REF
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 1
0 0 0 0
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 1
0 0 0 0
______________________________________________________________________________________
)
0001
0001
LSB
LSB
(
4096
1
)
+V
-V
REF
ANALOG OUTPUT
ANALOG OUTPUT
REF
+V
+V
+V
+V
+V
+V
Unipolar Output
-V
-V
(
(
REF
REF
REF
REF
REF
REF
REF
REF
———
———
2048
4096
2048
2048
(
(
(
(
0V
(
(
0V
(
(
———
———
———
———
———
———
———
———
4095
4096
2047
4096
4096
2047
2048
2048
2047
4096
2049
2048
2048
)
)
1
1
1
= ————
= -V
+V
)
)
)
)
)
)
)
)
REF
REF
2
The MAX525 outputs can be configured for bipolar
operation using Figure 11’s circuit.
where NB is the numeric value of the DAC’s binary
input code. Table 3 shows digital codes (offset binary)
and corresponding output voltages for Figure 11’s
circuit.
Figure 9. Unipolar Output Circuit
with Serial Interface
MAX525
V
REFAB
OUT
REFERENCE INPUTS
= V
DAC A
DAC B
DAC C
DAC D
REF
REFCD
[(2NB / 4096) - 1]
AGND
V
DD
+5V
Bipolar Output
DGND
FBA
FBB
FBC
FBD
OUTA
OUTB
OUTC
OUTD
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