Daisy-Chaining Devices

The serial output, DOUT, allows cascading of two or more

DACs. The data at DIN appears at DOUT, delayed by 16

clock cycles plus one clock width. For low power, DOUT is

a CMOS output that does not require an external pull-up

resistor. DOUT does not go into a high-impedance state

when CS is high. DOUT changes on SCLK’s falling edge

when CS is low. When CS is high, DOUT remains in the

state of the last data bit.

Any number of MAX504/MAX515 DACs can be daisy-

chained by connecting the DOUT of one device to the DIN

of the next device in the chain. For proper timing, ensure

Unipolar Configuration

unipolar output) by connecting BIPOFF and RFB to VOUT

(Figure 6). The converter operates from either single or

dual supplies in this configuration. See Table 1 for the

DAC-latch contents (input) vs. the analog VOUT (output).

voltage on REFIN.

connecting BIPOFF to AGND and RFB to VOUT (Figure

7). Table 2 shows the DAC-latch contents vs. VOUT. The

MAX504 operates from either single or dual supplies in

this mode. In this range,

The MAX515 is internally configured for unipolar gain of

2 operation.

Bipolar Configuration

A bipolar range is set up by connecting BIPOFF to

REFIN and RFB to VOUT, and operating from dual

(±5V) supplies (Figure 8). Table 3 shows the DAC-latch

contents (input) vs. VOUT (output). In this range,

Four-Quadrant Multiplication

The MAX504 can be used as a four-quadrant multiplier

by connecting BIPOFF to REFIN and RFB to VOUT, and

using (1) an offset binary digital code, (2) bipolar power

supplies, and (3) a bipolar analog input at REFIN within

where “G” is the gain (1 or 2) and “D” is the binary rep-

This formula is precise for unipolar operation. However,

for bipolar, offset binary operation, the MSB is really a

polarity bit. No resolution is lost because the number of

steps is the same. The output voltage, however, has

been shifted from a range of, for example, 0V to 4.096V

(G = 2) to a range of -2.048V to +2.048V.

Keep in mind that when using the DAC as a four-quad-

rant multiplier, the scale is skewed. Negative full scale

5V, Low-Power, Voltage-Output,

Serial 10-Bit DACs

10

______________________________________________________________________________________

MAX504

CONNECT BIPOFF

TO VOUT FOR G=1,

TO AGND FOR G=2,

OR TO REFIN FOR

BIPOLAR GAIN

INVERTED

R-2R DAC

DIN

DOUT

SCLK

CS

CLR

2.048V

REFIN

REFOUT

AGND DGND

33

µF

0.1

µF

0.1

µF

2R

2R

BIPOFF

RFB

VOUT

+5V

0V to -5V

MAX515

INVERTED

R-2R DAC

DIN

DOUT

SCLK

CS

REFIN

AGND

VOUT

MAX515

ONLY

0.1

µF

2R

2R

+5V

Figure 3a. MAX504 Typical Operating Circuit

Figure 3b. MAX515 Typical Operating Circuit