Low Noise,

Precision CMOS Amplifier

AD8655/AD8656

Rev. A

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© 2005 Analog Devices, Inc. All rights reserved.

FEATURES

PIN CONFIGURATIONS

Low noise: 2.7 nV/

√Hz @ f = 10 kHz

NC

1

–IN

2

+IN

3

V–

4

NC

8

V+

7

OUT

6

NC

5

AD8655

TOP VIEW

(Not to Scale)

NC = NO CONNECT

OUT A

1

–IN A

2

+IN A

3

V–

4

V+

8

OUT B

7

–IN B

6

+IN B

5

AD8656

TOP VIEW

(Not to Scale)

Offset voltage drift: 0.4 μV/°C typ and 2.3 μV/°C max

Bandwidth: 28 MHz

Rail-to-rail input/output

Unity gain stable

Figure 1. AD8655

8-Lead MSOP (RM-8)

Figure 2. AD8656

8-Lead MSOP (RM-8)

2.7 V to 5.5 V operation

−40°C to +125°C operation

APPLICATIONS

OUT A

1

–IN A

2

+IN A

3

V–

4

V+

8

OUT B

7

–IN B

6

+IN B

5

AD8656

TOP VIEW

(Not to Scale)

NC

1

–IN

2

+IN

3

V–

4

NC

8

V+

7

OUT

6

NC

5

NC = NO CONNECT

AD8655

TOP VIEW

(Not to Scale)

ADC and DAC buffers

Audio

Industrial controls

Precision filters

Digital scales

Figure 3. AD8655

8-Lead SOIC (R-8)

Figure 4. AD8656

8-Lead SOIC (R-8)

Strain gauges

PLL filters

GENERAL DESCRIPTION

The AD8655/AD8656 are the industry’s lowest noise, precision

CMOS amplifiers. They leverage the Analog Devices DigiTrim®

technology to achieve high dc accuracy.

The high precision performance of the AD8655/AD8656

improves the resolution and dynamic range in low voltage

applications. Audio applications, such as microphone pre-amps

and audio mixing consoles, benefit from the low noise, low

distortion, and high output current capability of the AD8655/

AD8656 to reduce system level noise performance and maintain

audio fidelity. The high precision and rail-to-rail input and

output of the AD8655/AD8656 benefit data acquisition, process

controls, and PLL filter applications.

The AD8655/AD8656 provide low noise (2.7 nV/√Hz @ 10 kHz),

low THD + N (0.0007%), and high precision performance

to swing rail-to-rail at the input and output enables designers

to buffer analog-to-digital converters (ADCs) and other wide

dynamic range devices in single-supply systems.

The AD8655/AD8656 are fully specified over the −40°C to

+125°C temperature range. The AD8655/AD8656 are available

in Pb-free, 8-lead MSOP and SOIC packages.