__________Applications Information

Unipolar Output

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

ence inputs have the same polarity. Figure 9 shows the

MAX5250 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 MAX5250 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 MAX5250 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.

Low-Power, Quad, 10-Bit Voltage-Output DAC

with Serial Interface

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13

Table 2. Unipolar Code Table

Table 3. Bipolar Code Table

( ) Sub-bits

DAC CONTENTS

ANALOG OUTPUT

MSB

LSB

1023

1111

1111

11(00)

1024

513

1000

0000

01(00)

1024

512

1000

0000

00(00)

1024

2

511

0111

1111

11(00)

1024

1

0000

0000

01(00)

1024

0000

0000

00(00)

0V

DAC CONTENTS

ANALOG OUTPUT

MSB

LSB

511

1111

1111

11(00)

512

1

1000

0000

01(00)

512

1000

0000

00(00)

0V

1

0111

1111

11(00)

512

511

0000

0000

01(00)

512

512

0000

0000

00(00)

512

MAX5250

DAC A

DAC B

DAC C

DAC D

OUTA

FBA

FBB

FBC

FBD

OUTB

OUTC

OUTD

DGND

AGND

REFAB

REFCD

REFERENCE INPUTS

+5V

Figure 9. Unipolar Output Circuit