Datasheet

__________Applications Information
Unipolar Output
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.
Bipolar Output
The MAX525 outputs can be configured for bipolar
operation using Figure 11’s circuit.
V
OUT
= V
REF
[(2NB / 4096) - 1]
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.
MAX525
Low-Power, Quad, 12-Bit Voltage-Output DAC
with Serial Interface
______________________________________________________________________________________ 13
Table 2. Unipolar Code Table
Table 3. Bipolar Code Table
Note: 1LSB = (V
REF
) (
4096
)
1
DAC CONTENTS
ANALOG OUTPUT
MSB LSB
4095
1111 1111 1111 +V
REF
( ———
)
4096
2049
1000 0000 0001 +V
REF
( ———
)
4096
2048 +V
REF
1000 0000 0000 +V
REF
( ——— )= ————
4096 2
2047
0111 1111 1111 +V
REF
( ——— )
4096
1
0000 0000 0001 +V
REF
( ——— )
4096
0000 0000 0000 0V
DAC CONTENTS
ANALOG OUTPUT
MSB LSB
2047
1111 1111 1111 +V
REF
(
——— )
2048
1
1000 0000 0001 +V
REF
(
——— )
2048
1000 0000 0000 0V
1
0111 1111 1111 -V
REF
(
——— )
2048
2047
0000 0000 0001 -V
REF
( ——— )
2048
2048
0000 0000 0000 -V
REF
( ——— )= -V
REF
2048
MAX525
DAC A
DAC B
DAC C
DAC D
OUTA
FBA
FBB
FBC
FBD
OUTB
OUTC
OUTD
DGNDAGND
REFAB
REFCD
REFERENCE INPUTS
+5V
V
DD
Figure 9. Unipolar Output Circuit