Ultra Low Distortion IF Dual VGA

Preliminary Technical Data

AD8376

Rev. PrD

March 13, 2007

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.

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

Tel: 781.329.4700

www.analog.com

Fax: 781.326.8703

© 2007 Analog Devices, Inc. All rights reserved.

FEATURES

Dual Independent Digitally Controlled VGAs

-4 to 20dB Gain Range

1 dB Step Size

± 0.2 dB

Differential input and output

150 Ω Differential Input

Open Collector Differential Output

8.7 dB noise figure @ maximum gain

OIP3 of ~50dBm at 140MHz

−3 dB bandwidth of 700 MHz

Excellent Channel to Channel Isolation

Two Parallel 5-bit Control Interfaces

Wide input dynamic range

Power-down Control

Single 5V Supply Operation

32 Lead LFCSP 5 x 5 mm Package

APPLICATIONS

Differential ADC drivers

Main and Diverstiy IF Sampling Receivers

High Output Power IF Amplification

Multi-channel Receivers

Instrumentation

GENERAL DESCRIPTION

The AD8376 is a dual channel digitally controlled, variable gain

wide bandwidth amplifier that provides precise gain control,

high IP3 and low noise figure. The excellent distortion

performance and high signal bandwidth makes the AD8376 an

excellent gain control device for a variety of receiver

applications.

For wide input dynamic range applications, the AD8376 pro-

vides a broad 24 dB gain range with 1 dB resolution. The gain of

each channel is adjusted through dedicated 5-pin control

interfaces and can be driven using standard TTL levels. The

open-collector outputs provide a flexible interface, allowing the

overall signal gain to be set by the loading resistance. The

AD8376 offers a maximum trans-conductance gain of

the load resistance. When driving a 150 Ω differential load, the

maximum signal gain will be 20 dB.

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

Using a high speed SiGe process and incorporating proprietary

distortion cancellation techniques, the AD8376 achieves

50 dBm output IP3 at 140 MHz.

Each channel of the AD8376 can be individually powered on by

applying the appropriate logic level to the ENBA and ENBB

power enable pins. The quiescent current of the AD8376 is

typically 130 mA per channel. When powered down, the

AD8376 consumes less than 5mA and offers excellent input to

output isolation, lower than -50 dB at 200 MHz.

Fabricated on an ADI’s high speed SiGe process, the AD8376

provides precise gain adjustment capabilities with good distortion

performance. The AD8376 amplifier comes in a compact,

thermally enhanced 5 x 5mm 32-lead LFCSP package and

operates over the temperature range of −40°C to +85°C.