AD557–SPECIFICATIONS

Model

Min

Typ

Max

Units

RESOLUTION

8

Bits

RELATIVE ACCURACY

0 to + 70

°C

± 1/2

1

LSB

OUTPUT

Ranges

0 to + 2.56

V

Current Source

+5

mA

Sink

Internal Passive

Pull-Down to Ground

2

OUTPUT SETTLING TIME

3

0.8

1.5

µs

FULL-SCALE ACCURACY

4

@ +25

°C

± 1.5

± 2.5

LSB

± 2.5

± 4.0

LSB

ZERO ERROR

@ +25

°C

± 1

LSB

± 3

LSB

MONOTONICITY

5

Guaranteed

DIGITAL INPUTS

Input Current

100

µA

Data Inputs, Voltage

Bit On—Logic “1”

2.0

V

Bit On—Logic “0”

0

0.8

V

Control Inputs, Voltage

On—Logic “1”

2.0

V

On—Logic “0”

0

0.8

V

Input Capacitance

4

pF

TIMING

6

225

ns

300

ns

10

ns

10

ns

225

ns

300

ns

POWER SUPPLY

2.56 Volt Range

+4.5

+5.5

V

25

mA

Rejection Ratio

0.03

%/%

75

125

mW

OPERATING TEMPERATURE RANGE

0

+70

°C

NOTES

ideal transfer point on a straight line from the zero the the full scale of the device.

Ω.

±1/2 LSB. Negative-

going steps to zero are slower, but can be improved with an external pull-down.

±1 LSB.

Specifications subject to change without notice.

PIN CONFIGURATIONS

DIP

10

9

13

12

11

16

15

14

8

1

2

3

4

7

6

5

TOP VIEW

(Not to Scale)

AD557

LSB BIT 8

GND

BIT 7

BIT 6

BIT 5

CS

GND

BIT 4

BIT 3

BIT 2

MSB BIT 1

CE

PLCC

20 19

18

1

2

3

4

5

6

7

8

910

11 12

13

14

15

16

17

TOP VIEW

(Not to Scale)

PIN 1

IDENTIFIER

BIT 6

BIT 5

NC

BIT 4

BIT 3

GND

NC

GND

NC = NO CONNECT

AD557

ABSOLUTE MAXIMUM RATINGS

*

Digital Inputs (Pins 1–10) . . . . . . . . . . . . . . . . . . 0 V to +7.0 V

Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450 mW

Storage Temperature Range

N/P (Plastic) Packages . . . . . . . . . . . . . . . . –25

°C to +100°C

Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . . 300

°C

Thermal Resistance

Junction to Ambient/Junction to Case

N/P (Plastic) Packages . . . . . . . . . . . . . . . . . . 140/55

°C/W

*Stresses above those listed under “Absolute Maximum Ratings” may cause

permanent damage to the device. This is a stress rating only and functional

operation of the device at these or any other conditions above those indicated

in the operational section of this specification is not implied. Exposure to absolute

maximum rating conditions for extended periods may affect device reliability.

REV. A

–2–

ORDERING GUIDE

Model

Temperature Range

Package Option*

AD557JN

0

°C to +70°C

N-16

AD557JP

0

°C to +70°C

P-20A

*N = Plastic DIP; P = Plastic Leaded Chip Carrier.

CIRCUIT DESCRIPTION

The AD557 consists of four major functional blocks fabricated

on a single monolithic chip (see Figure 1). The main D/A con-

verter section uses eight equally weighted laser-trimmed current

sources switched into a silicon-chromium thin-film R/2R resistor

ladder network to give a direct but unbuffered 0 mV to 400 mV

output range. The transistors that form the DAC switches are

PNPs; this allows direct positive-voltage logic interface and a

zero-based output range.