CONNECTION DIAGRAMS

1

2

3

4

8

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6

5

TOP VIEW

(Not to Scale)

AD680

TP*

+V

IN

TEMP

GND

TP*

TP*

NC

NC = NO CONNECT

TP DENOTES FACTORY TEST POINT.

NO CONNECTIONS SHOULD BE MADE

TO THESE PINS.

*

3

2

1

+V

IN

V

OUT

GND

AD680

BOTTOM VIEW

(Not to Scale)

REV. C

Information furnished by Analog Devices is believed to be accurate and

reliable. However, no responsibility is assumed by Analog Devices for its

use, nor for any infringements of patents or other rights of third parties

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

a

Low Power, Low Cost

2.5 V Reference

AD680*

FEATURES

Low Quiescent Current: 250

A max

Laser Trimmed to High Accuracy:

2.5 V

5 mV max (AN, AR Grade)

Trimmed Temperature Coefficient:

20 ppm/ C max (AN, AR Grade)

Low Noise: 8

V p-p from 0.1 Hz to 10 Hz

250 nV/

√Hz Wideband

Temperature Output Pin (N, R Packages)

Available in Three Package Styles:

8-Pin Plastic DIP, 8-Pin SOIC and 3-Pin TO-92

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 617/329-4700

Fax: 617/326-8703

PRODUCT DESCRIPTION

The AD680 is a bandgap voltage reference which provides a

fixed 2.5 V output from inputs between 4.5 V and 36 V. The

architecture of the AD680 enables the reference to be operated

at a very low quiescent current while still realizing excellent dc

characteristics and noise performance. Trimming of the high

stability thin-film resistors is performed for initial accuracy and

temperature coefficient, resulting in low errors over temperature.

The precision dc characteristics of the AD680 make it ideal for

use as a reference for D/A converters which require an external

precision reference. The device is also ideal for A/D converters

and, in general, can offer better performance than the standard

on-chip references.

Based upon the low quiescent current of the AD680, which

rivals that of many incomplete two-terminal references, the

AD680 is recommended for low power applications such as

hand-held battery equipment.

A temperature output pin is provided on the 8-pin package ver-

sions of the AD680. The temperature output pin provides an

output voltage that varies linearly with temperature and allows

the AD680 to be configured as a temperature transducer while

providing a stable 2.5 V output.

The AD680 is available in five grades. The AD680AN is speci-

fied for operation from –40

°C to +85°C, while the AD680JN

is specified for 0

°C to +70°C operation. Both the AD680AN

and AD680JN are available in 8-pin plastic DIP packages. The

AD680AR is specified for operation from –40

°C to +85°C,

while the AD680JR is specified for 0

°C to +70°C operation.

Both are available in an 8-pin Small Outline IC (SOIC) pack-

age. The AD680JT is specified for 0

°C to +70°C operation and

is available in a 3-pin TO-92 package.

*Protected by U.S. Patent Nos. 4,902,959; 4,250,445 and 4,857,862.

PRODUCT HIGHLIGHTS

1. The AD680 bandgap reference operates on a very low quies-

cent current which rivals that of many two-terminal refer-

ences. This makes the complete, higher accuracy AD680

ideal for use in power sensitive applications.

2. Laser trimming of both initial accuracy and temperature

coefficients results in low errors over temperature without the

use of external components. The AD680AN and AD680AR

have a maximum variation of 6.25 mV between –40

°C and

+85

°C.

3. The AD680 noise is low, typically 8

µV p-p from 0.1 Hz to

10 Hz. Spectral density is also low, typically 250 nV/

√Hz.

4. The temperature output pin on the 8-pin package versions

enables the AD680 to be configured as a temperature trans-

ducer.

5. Plastic DIP packaging provides machine insertability, while

SOIC packaging provides surface mount capability. TO-92

packaging offers a cost effective alternative to two-terminal

references, offering a complete solution in the same package

in which two-terminal references are usually found.