Applications Information

Unipolar Output

Figure 6 shows the MAX5175/MAX5177 configured for

unipolar, rail-to-rail operation with a gain of +2V/V.

Table 2 lists the codes for unipolar output voltages. The

Bipolar Output

Figure 7 shows the MAX5175/MAX5177 configured for

bipolar output operation. The output voltage is given by

the following equation (FB = OUT):

where N represents the numeric value of the DAC’s

nal reference. Table 3 shows digital codes and the cor-

responding output voltage for Figure 7’s circuit.

Daisy-Chaining Devices

The serial data output pin (DOUT) allows multiple

MAX5175/MAX5177s to be daisy-chained together as

shown in Figure 8. The advantage of this is that only

two lines are needed to control all of the DACs on the

line. The disadvantage is that it takes

n commands to

program the DACs. Figure 9 shows several MAX5175/

MAX5177s sharing one common DIN signal line. In this

configuration the data bus is common to all devices;

however, more I/O lines are required because each

device needs a dedicated CS line. The advantage of

this configuration is that only one command is needed

to program any DAC.

V

V

2N

4096

1

OUT

REF

=−













Low-Power, Serial, 12-Bit DACs with

Force/Sense Voltage Output

______________________________________________________________________________________

13

Table 2. Unipolar Code Table (Circuit of

Figure 6)

11 1111 1111 11 (00)

10 0000 0000 01 (00)

01 1111 1111 11 (00)

10 0000 0000 00 (00)

00 0000 0000 00 (00)

00 0000 0000 01 (00)

0

ANALOG OUTPUT

DAC CONTENTS

MSB

LSB

MAX5175

MAX5177

DAC

REF

OUT

10k

10k

GND

+5V/+3.3V

FB

Figure 6. Unipolar Output Circuit (Rail-to-Rail)

DAC

V+

V-

+5V/+3.3V

R1 = R2 = 10k

Ω ± 0.1%

MAX5175

MAX5177

REF

10k

10k

FB

OUT

GND

Figure 7. Bipolar Output Circuit

Table 3. Bipolar Code Table (Circuit of

Figure 7)

11 1111 1111 11 (00)

ANALOG OUTPUT

10 0000 0000 01 (00)

01 1111 1111 11 (00)

10 0000 0000 00 (00)

DAC CONTENTS

MSB

LSB

00 0000 0000 00 (00)

00 0000 0000 01 (00)