AD780 Analog Devices Data Handbook/Manual

High Precision Reference

AD780

FEATURES FUNCTIONAL BLOCK DIAGRAM Pin programmable 2.5 V or 3.0 V output +VIN NC

Ultralow drift: 3 ppm/°C max

AD780

High accuracy: 2.5 V or 3.0 V ±1 m V max Low noise: 100 n V/√Hz

Noise reduction capability NC

Low quiescent current: 1 m A max

Output trim capability

Plug-in upgrade for present references Q7 R16

R5 TRIM

Temperature output pin

Series or shunt mode operation (±2.5 V, ±3.0 V) R15

GND O/P SELECT 2.5V – NC

NC = NO CONNECT

3.0V – GND

Figure 1.

PRODUCT DESCRIPTION The AD780 is a pin compatible performance upgrade for the

LT1019(A)–2.5 and the AD680. The latter is targeted toward

The AD780 is an ultrahigh precision band gap reference voltage

low power applications.

that provides a 2.5 V or 3.0 V output from inputs between 4.0 V and 36 V. Low initial error and temperature drift combined with

The AD780 is available in three grades in PDIP and SOIC

low output noise and the ability to drive any value of www.BDTIC. om/ADI

packages. The AD780AN, AD780AR, AD780BN, AD780BR, and

capacitance make the AD780 the ideal choice for enhancing the

AD780CR are specified for operation from −40°C to +85°C.

performance of high resolution ADCs and DACs, and for any

general-purpose precision reference application. A unique low PRODUCT HIGHLIGHTS

headroom design facilitates a 3.0 V output from a 5.0 V 10%

1. The AD780 provides a pin programmable 2.5 V or 3.0 V

input, providing a 20% boost to the dynamic range of an ADC

output from a 4 V to 36 V input.

over performance with existing 2.5 V references.

2. Laser trimming of both initial accuracy and temperature

The AD780 can be used to source or sink up to 10 m A, and can

coefficients results in low errors over temperature without

be used in series or shunt mode, thus allowing positive or

the use of external components. The AD780BN has a

negative output voltages without external components. This

maximum variation of 0.9 m V from −40°C to +85°C.

makes it suitable for virtually any high performance reference

application. Unlike some competing references, the AD780 has 3. For applications that require even higher accuracy, an no region of possible instability. The part is stable under all load optional fine-trim connection is provided.

conditions when a 1 µF bypass capacitor is used on the supply.

4. The AD780 noise is extremely low, typically 4 m V p-p from A temperature output pin on the AD780 provides an output 0.1 Hz to 10 Hz and a wideband spectral noise density of voltage that varies linearly with temperature, allowing the part typically 100 n V/√Hz. This can be further reduced, if

to be configured as a temperature transducer while providing a desired, by using two external capacitors. stable 2.5 V or 3.0 V output.

5. The temperature output pin enables the AD780 to be configured as a temperature transducer while providing a stable output reference.

Rev. E 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 that may result from its use.

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

Specifications subject to change without notice. No license is granted by implication

or otherwise under any patent or patent rights of Analog Devices. Trademarks and Tel: 781.329.4700 www.analog.com registered trademarks are the property of their respective owners. Fax: 781.326.8703 © 2004 Analog Devices, Inc. All rights reserved.