Daisy-Chaining Devices

The serial data output pin (DOUT) allows multiple

MAX5171/MAX5173s 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 MAX5171/

MAX5173s sharing one common DIN signal line. In this

configuration, the data bus is common to all devices.

However, this configuration uses more I/O lines

because each device requires a dedicated CS line.

The benefit is that only one command is needed to pro-

gram any DAC.

Using an AC Reference

The MAX5171/MAX5173 accepts reference voltages

with AC components as long as the reference voltage

technique for applying a sine-wave signal to the REF.

The reference voltage must remain above AGND.

Digitally Programmable Current Source

The circuit of Figure 11 places an NPN transistor

(2N3904 or similar) within the op amp feedback loop to

implement a digitally programmable, unidirectional cur-

rent source. The output current is calculated with the

following equation:

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

code and R is the sense resistor shown in Figure 11.

I

VN

R

OUT

REF

=

⋅

⋅16384

Low-Power, Serial, 14-Bit DACs

with Force/Sense Voltage Output

______________________________________________________________________________________

13

DAC CONTENTS

MSB

LSB

11 1111 1111 1111

10 0000 0000 0001

2

2

ANALOG OUTPUT

10 0000 0000 0000

2

01 1111 1111 1111

2

00 0000 0000 0001

2

00 0000 0000 0000

0

DAC

V+

V-

+5V/+3.3V

REF

10k

10k

FB

OUT

GND

MAX5171

MAX5173

Figure 7. Bipolar Output Circuit

Table 2. Unipolar Code Table

(Circuit of Figure 6)

Table 3. Bipolar Code Table

(Circuit of Figure 7)

MAX5171

MAX5173

DAC

REF

OUT

10k

10k

GND

+5V/+3.3V

FB

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

DAC CONTENTS

MSB

LSB

11 1111 1111 1111

10 0000 0000 0001

ANALOG OUTPUT

01 1111 1111 1111

00 0000 0000 0001

10 0000 0000 0000

00 0000 0000 0000