_______________General Description

The MAX520/MAX521 are quad/octal, 8-bit voltage-output

digital-to-analog converters (DACs) with simple 2-wire ser-

ial interfaces that allow communication between multiple

devices. They operate from a single +5V supply and their

reference input range includes both supply rails.

The MAX521 includes rail-to-rail output buffer amplifiers for

reduced system size and component count when driving

loads. The MAX520’s unbuffered voltage outputs reduce

the device’s total supply current to 4µA and provide

increased accuracy at low output currents.

The MAX520/MAX521 feature a serial interface and internal

software protocol, allowing communication at data rates up

to 400kbps. The interface, combined with the double-

buffered input configuration, allows the DAC registers to be

updated individually or simultaneously. In addition, the

devices can be put into a low-power shutdown mode that

reduces supply current to 4µA. Power-on reset ensures the

DAC outputs are at 0V when power is initially applied.

The MAX520 is available in 16-pin DIP and wide SO pack-

ages, as well as a space-saving 20-pin SSOP. The

MAX521 comes in 20-pin DIP and 24-pin SO packages, as

well as a space-saving 24-pin SSOP.

________________________Applications

Minimum Component Analog Systems

Digital Offset/Gain Adjustment

Industrial Process Control

Automatic Test Equipment

Programmable Attenuators

____________________________Features

o Single +5V Supply

o Simple 2-Wire Serial Interface

o Outputs Swing Rail to Rail:

Unbuffered Outputs (MAX520)

Buffered Outputs (MAX521)

o 1%-Accurate Trimmed Output Resistance (MAX520A)

o Ultra-Low 4µA Supply Current (MAX520)

o Individual DACs Have Separate Reference Inputs

o Power-On Reset Clears All Latches

o 4µA Power-Down Mode

Quad/Octal, 2-Wire Serial 8-Bit DACs

with Rail-to-Rail Outputs

________________________________________________________________

Maxim Integrated Products

1

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

OUT1

OUT2

OUT3

REF2

REF3

AD2

AD1

AD0

OUT0

REF1

REF0

AGND

DGND

SCL

SDA

TOP VIEW

MAX520

DIP/SO

_________________Pin Configurations

INPUT

LATCH 0

8-BIT

SHIFT REGISTER

SCL

REF0

SDA

REF1

OUTPUT

LATCH 0

DAC0

OUT0

1

MAX520

ADDRESS

COMPARATOR

START/STOP

DETECTOR

DECODE

OUTPUT

LATCH 1

DAC1

OUT1

4

8

INPUT

LATCH 2

OUTPUT

LATCH 2

DAC2

OUT2

OUT3

INPUT

LATCH 3

OUTPUT

LATCH 3

DAC3

REF3

REF2

AD2

AD1

AD0

1

INPUT

LATCH 1

1

1

_______________Functional Diagrams

______________Ordering Information

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800

19-0378; Rev 3; 9/96

PART

†

MAX520ACPE

MAX520BCPE

MAX520ACWE

0°C to +70°C

0°C to +70°C

0°C to +70°C

TEMP. RANGE

PIN-PACKAGE

16 Plastic DIP

16 Plastic DIP

16 Wide SO

TUE

(LSB)

1

1

1

Pin Configurations continued at end of data sheet.

Functional Diagrams continued at end of data sheet.

MAX520BCWE

0°C to +70°C

16 Wide SO

1

Ordering Information continued at end of data sheet.

output resistance.