Low-Cost, Voltage-Output, 16-Bit DACs in µMAX

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11

Bipolar Configuration

The MAX5204–MAX5207 are designed for unipolar opera-

tion, but can be used in bipolar applications with an exter-

nal amplifier and resistors. Figure 5 shows the

MAX5204–MAX5207 configured for bipolar operation. The

op amp is set for unity gain. Table 1 lists the offset binary

Layout Considerations

Digital and AC transient signals coupling to AGND can

create noise at the output. Connect AGND to the high-

est quality ground available. Use proper grounding

techniques, such as a multilayer board with a low-

inductance ground plane. Wire-wrapped boards and

sockets are not recommended. For optimum system

performance, use printed circuit (PC) boards with sep-

arate analog and digital ground planes. Connect the

two ground planes together at the low-impedance

power-supply source. Connect DGND and AGND pins

together at the IC. The best ground connection is

achieved by connecting the DAC’s DGND and AGND

together, and then connecting that point to the system

analog ground plane. If the DAC’s DGND is connected

to the system digital ground, digital noise can get

through the DAC’s analog portion.

Chip Information

TRANSISTOR COUNT: 8764

PROCESS: BiCMOS

CLR

AGND

REF

DIN

SCLK

CS

DGND

BIPOLAR OUT

(

LDAC

OUT

MC68XXXX

10

µF

0.1

µF

0.1

µF

10

µF

PCS0

MOSI

SCLK

+5V

R

R

MAX5204–

MAX5207

MAX400

Figure 5. MAX5204–MAX5207 Typical Operating Circuit—Bipolar Output

DAC LATCH CONTENTS

MSB

LSB

1111 1111 1111 1111

× (32,767 / 32,768)

1000 0000 0000 0001

× (1 / 32,768)

1000 0000 0000 0000

0V

0111 1111 1111 1111

× (1 / 32,768)

0000 0000 0000 0000

× (32,768 / 32,768)

Table 1. Bipolar Code Table