General-Purpose, Low Cost,

DC-Coupled VGA

Data Sheet

AD8337

Rev. D

Document Feedback

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibilityis assumedbyAnalogDevicesforitsuse,norforanyinfringementsof patentsorother

rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.

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

Tel: 781.329.4700

©2005–2016 Analog Devices, Inc. All rights reserved.

Technical Support

www.analog.com

FEATURES

Low noise

Voltage noise = 2.2 nV/√Hz

Current noise = 4.8 pA/√Hz (positive input)

Wide bandwidth (−3 dB) = 280 MHz

Nominal gain range: 0 dB to 24 dB (preamp gain = 6 dB)

Gain scaling: 19.7 dB/V

DC-coupled

Single-ended input and output

High speed uncommitted op amp input

Supplies: +5 V, ±2.5 V, or ±5 V

Low power: 78 mW with ±2.5 V supplies

APPLICATIONS

Gain trim

PET scanners

High performance AGC systems

I/Q signal processing

Video

Industrial and medical ultrasound

Radar receivers

GENERAL DESCRIPTION

The AD8337 is a low noise, single-ended, linear-in-dB, general-

purpose, variable gain amplifier (VGA) usable at frequencies

from dc to 100 MHz; the −3 dB bandwidth is 280 MHz.

Excellent bandwidth uniformity across the entire gain range

and low output referred noise make the AD8337 ideal for

gain trim applications and for driving high speed analog-to-

digital converters (ADCs).

Excellent dc characteristics combined with high speed make the

AD8337 particularly suited for industrial ultrasound, PET

scanners, and video applications. Dual-supply operation enables

gain control of negative going pulses, such as those generated

by photodiodes or photomultiplier tubes.

The AD8337 uses the Analog Devices, Inc., exclusive X-AMP®

architecture with 24 dB gain range scaled to 19.7 dB/V,

referenced to VCOM.

The AD8337 preamplifier is configured in a current feedback

architecture optimized for gains of 6 dB to 24 dB. The AD8337

is characterized by a noninverting preamplifier gain of 2× using a

pair of 100 Ω resistors. The attenuator has a range of 24 dB, and

the output amplifier has a fixed gain of 8× (18.06 dB). The lowest

nominal gain range is 0 dB to 24 dB and can be shifted up or down

by adjusting the preamplifier gain. Series connected AD8337

devices provide larger gain ranges, interstage filtering to suppress

noise and distortion, and nulling of offset voltages.

FUNCTIONAL BLOCK DIAGRAM

VOUT

EIGHT SECTIONS

GAIN

GAIN CONTROL

INTERFACE

18dB

INPP

PRAO

VCOM

INPN

PREAMP

Figure 1