ANALOG DEVICES AD822 Service Manual

Single-Supply, Rail-to-Rail

FEATURES

True single-supply operation

Output swings rail-to-rail Input voltage range extends below ground Single-supply capability from 5 V to 30 V Dual-supply capability from ±2.5 V to ±15 V

High load drive

Capacitive load drive of 350 pF, G = +1 Minimum output current of 15 mA

Excellent ac performance for low power

800 µA maximum quiescent current per amplifier Unity-gain bandwidth: 1.8 MHz Slew rate of 3 V/s

Good dc performance

800 µV maximum input offset voltage 2 µV/°C typical offset voltage drift 25 pA maximum input bias current

Low noise

13 nV/√Hz @ 10 kHz No phase inversion

APPLICATIONS

Battery-powered precision instrumentation Photodiode preamps Active filters 12-bit to 14-bit data acquisition systems Medical instrumentation Low power references and regulators

Low Power FET-Input Op Amp

AD822

CONNECTION DIAGRAM

OUT1

–IN1

+IN1

V–

AD822

Figure 1. 8-Lead PDIP (N Suffix);

8-Lead MSOP (RM Suffix);

and 8-Lead SOIC_N (R Suffix)

GENERAL DESCRIPTION

The AD822 is a dual precision, low power FET input op amp that can operate from a single supply of 5 V to 30 V or dual supplies of ±2.5 V to ±15 V. It has true single-supply capability with an input voltage range extending below the negative rail, allowing the AD822 to accommodate input signals below ground in the single-supply mode. Output voltage swing extends to within 10 mV of each rail, providing the maximum output dynamic range.

100

V+ OUT2

–IN2

+IN2

00874-001

Rev. I

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. 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 registered trademarks are the property of their respective owners.

INPUT VOLTAGE NOISE (nV/Hz)

10 10k

Figure 2. Input Voltage Noise vs. Frequency

100

FREQUENCY ( Hz )

Offset voltage of 800 µV maximum, offset voltage drift of 2 µV/°C, input bias currents below 25 pA, and low input voltage noise provide dc precision with source impedances up to a gigaohm. The 1.8 MHz unity-gain bandwidth, –93 dB THD at 10 kHz, and 3 V/µs slew rate are provided with a low supply current of 800 µA per amplifier.

00874-002