Low-Power, 13-Bit Voltage-Output DACs

with Serial Interface

12

______________________________________________________________________________________

Figure 7 shows a method of connecting several

MAX535/MAX5351s. In this configuration, the clock and

the data bus are common to all devices and separate

chip-select lines are used for each IC.

__________Applications Information

Unipolar Output

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

ence input have the same polarity. Figure 8 shows the

MAX535/MAX5351 unipolar output circuit, which is also

the typical operating circuit. Table 2 lists the unipolar

output codes.

For rail-to-rail output, see Figure 9. This circuit shows

the MAX535/MAX5351 with the output amplifier config-

ured with a closed-loop gain of +2 to provide 0V to 5V

full-scale range when a 2.5V reference is used. When

using the MAX5351 with a 1.25V reference, this circuit

provides a 0V to 2.5V full-scale range.

Bipolar Output

The MAX535/MAX5351 output can be configured for

bipolar operation using Figure 10’s circuit.

where NB is the numeric value of the DAC’s binary input

code. Table 3 shows digital codes (offset binary) and

the corresponding output voltage for Figure 10’s circuit.

Using an AC Reference

In applications where the reference has AC-signal com-

ponents, the MAX535/MAX5351 have multiplying capa-

bility within the reference input range specifications.

Figure 11 shows a technique for applying a sine-wave

signal to the reference input where the AC signal is off-

set before being applied to REF. The reference voltage

must never be more negative than GND.

TO OTHER

SERIAL DEVICES

MAX535

MAX5351

DIN

SCLK

CS

MAX535

MAX5351

DIN

SCLK

CS

MAX535

MAX5351

DIN

SCLK

CS

DIN

SCLK

CS1

CS2

CS3

Figure 7. Multiple MAX535/MAX5351s Sharing Common DIN and SCLK Lines

Table 2. Unipolar Code Table

ANALOG OUTPUT

11111

1111

1111

10000

0000

0001

DAC CONTENTS

MSB

LSB

10000

0000

0000

01111

1111

1111

00000

0000

0000

0V

00000

0000

0001

+V

8191

8192

REF









+V

4097

8192

REF









+V

4096

8192

REF









=

2

+V

4095

8192

REF









+V

1

8192

REF







