Datasheet

MAX5251
+3V, Quad, 10-Bit Voltage-Output DAC
with Serial Interface
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__________Applications Information
Unipolar Output
For a unipolar output, the output voltages and the refer-
ence inputs have the same polarity. Figure 9 shows the
MAX5251 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 MAX5251 with the output amplifiers configured with
a closed-loop gain of +2.6 to provide 0V to 3.25V full-
scale range when a 1.25V reference is used.
Bipolar Output
The MAX5251 outputs can be configured for bipolar
operation using Figure 11’s circuit:
V
OUT
= V
REF
[(2NB / 1024) - 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.
Table 2. Unipolar Code Table
Table 3. Bipolar Code Table
DAC CONTENTS
ANALOG OUTPUT
MSB LSB
1023
1111 1111 11(00) +V
REF
( ———
)
1024
513
1000 0000 01(00) +V
REF
( ———
)
1024
512 +V
REF
1000 0000 00(00) +V
REF
( ——— )= ————
1024 2
511
0111 1111 11(00) +V
REF
( ——— )
1024
1
0000 0000 01(00) +V
REF
( ——— )
1024
0000 0000 00(00) 0V
DAC CONTENTS
ANALOG OUTPUT
MSB LSB
511
1111 1111 11(00) +V
REF
(
——— )
512
1
1000 0000 01(00) +V
REF
(
——— )
512
1000 0000 00(00) 0V
1
0111 1111 11(00) -V
REF
(
——— )
512
511
0000 0000 01(00) -V
REF
( ——— )
512
512
0000 0000 00(00) -V
REF
( ——— )= -V
REF
512
MAX5251
DAC A
DAC B
DAC C
DAC D
OUTA
FBA
FBB
FBC
FBD
OUTB
OUTC
OUTD
DGNDAGND
REFAB
REFCD
REFERENCE INPUTS
+3.3V
V
DD
Figure 9. Unipolar Output Circuit
( ) Sub-bits