__________Applications Information

Unipolar Output

For a unipolar output, the output voltages and the refer-

ence inputs have the same polarity. Figure 9 shows the

MAX5253 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 MAX5253 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 MAX5253 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.

+3V, Quad, 12-Bit Voltage-Output DAC

with Serial Interface

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13

Table 2. Unipolar Code Table

Table 3. Bipolar Code Table

DAC CONTENTS

ANALOG OUTPUT

MSB

LSB

4095

1111

1111

1111

4096

2049

1000

0000

0001

4096

2048

1000

0000

0000

4096

2

2047

0111

1111

1111

4096

1

0000

0000

0001

4096

0000

0000

0000

0V

DAC CONTENTS

ANALOG OUTPUT

MSB

LSB

2047

1111

1111

1111

2048

1

1000

0000

0001

2048

1000

0000

0000

0V

1

0111

1111

1111

2048

2047

0000

0000

0001

2048

2048

0000

0000

0000

2048

MAX5253

DAC A

DAC B

DAC C

DAC D

OUTA

FBA

FBB

FBC

FBD

OUTB

OUTC

OUTD

DGND

AGND

REFAB

REFCD

REFERENCE INPUTS

+3.3V

Figure 9. Unipolar Output Circuit