+3V, Quad, 10-Bit Voltage-Output DAC

with Serial Interface

______________________________________________________________________________________

13

__________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:

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)

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

MAX5251

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

( ) Sub-bits