MAX504 データシートの表示（PDF） - Maxim Integrated

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MAX504

5V, Low-Power, Voltage-Output, Serial 10-Bit DACs

Maxim Integrated 

5V, Low-Power, Voltage-Output,

Serial 10-Bit DACs

DIN DOUT SCLK CS CLR

REFIN

REFOUT

INVERTED

R-2R DAC

2.048V MAX504

33µF

AGND DGND

VDD VSS

0.1µF

0.1µF

VOUT

2R

RFB

2R

BIPOFF CONNECT BIPOFF

TO VOUT FOR G=1,

TO AGND FOR G=2,

+5V

OR TO REFIN FOR

BIPOLAR GAIN

0V to -5V

REFIN

DIN SCLK CS DOUT

INVERTED

R-2R DAC

2R

MAX515

2R

AGND

VDD

0.1µF

MAX515

ONLY

+5V

VOUT

Figure 3a. MAX504 Typical Operating Circuit

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

that tCL (SCLK low) is greater than tDO + tDS.

Unipolar Configuration

The MAX504 is configured for a gain of 1 (0V to VREFIN

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).

In this range, 1LSB = VREFIN (2 -10), where VREF is the

voltage on REFIN.

A gain of 2 (0V to 2VREFIN unipolar output) is set up by

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,

1LSB = (2)(VREFIN)(2 -10) = (VREFIN)(2 -9).

The MAX515 is internally configured for unipolar gain of

2 operation.

Figure 3b. MAX515 Typical Operating Circuit

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,

1LSB = VREFIN (2 -9).

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

the range VSS + 2V to VDD - 2V, as shown in Figure 9.

In general, a 10-bit DAC’s output is (D)(VREFIN)(G),

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

resentation of the digital input divided by 210 or 1,024.

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

is -VREFIN, while positive full scale is +VREFIN - 1LSB.

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