LMH6514

www.ti.com

SNOSB06 – JANUARY 2008

LMH6514 600 MHz, Digital Controlled, Variable Gain Amplifier

Check for Samples: LMH6514

1

FEATURES

DESCRIPTION

The LMH6514 is a high performance, digitally

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•

Adjustable Gain with a 42 dB Range

controlled variable gain amplifier (DVGA). It combines

•

Precise 6.02 dB Gain Steps

precision gain control with a low noise, ultra-linear,

•

Parallel 3 Bit Gain Control

differential amplifier. Typically, the LMH6514 drives a

high performance ADC in a broad range of mixed

•

On Chip Register Gain Setting

signal and digital communication applications such as

•

Fully Differential Signal Path

mobile

radio

and

cellular

base

stations

where

•

Single Ended to Differential Capable

automatic gain control (AGC) is required to increase

system dynamic range. When used in conjunction

•

200

Ω Input Impedance

with a high speed ADC, system dynamic range can

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Small Footprint (4 mm x 4 mm) WQFN Package

be extended by up to 42 dB.

The LMH6514 has a differential input and output

APPLICATIONS

allowing large signal swings on a single 5V supply. It

•

Cellular Base Stations

is designed to accept signals from RF elements and

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IF Sampling Receivers

maintain a terminated impedance environment. The

input impedance is 200

Ω resistive. The output

•

Instrumentation

impedance is either 200

Ω or 400Ω and is user

•

Modems

selectable. A unique internal architecture allows use

•

Imaging

with both single ended and differential input signals.

•

Differential Line Receiver

Input signals to the LMH6514 are scaled by a highly

linear,

digitally

controlled

attenuator

with

seven

KEY SPECIFICATIONS

accurate 6 dB steps. The attenuator output provides

the input signal for a high gain, ultra linear differential

•

600 MHz bandwidth at 100

Ω load

transconductor. The transconductor differential output

•

39 dBm OIP3 at 75 MHz, 200

Ω load

current can be converted into a voltage by using the

•

26 dB to 38 dB maximum gain

on-chip 200

Ω or 400Ω loads. The transconductance

gain is 0.1 Amp/Volt resulting in a maximum voltage

•

Selectable output impedance of 200

Ω or 400Ω.

gain of +32 dB when driving a 200

Ω load, or 38 dB

•

8.3 dB noise figure

when driving the 400

Ω load. On chip digital latches

•

5 ns gain step switching time

are provided for local storage of the gain setting. The

gain step settling time is 5 ns and care has been

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100 mA supply current

taken to reduce the sensitivity of bandwidth and

phase to gain setting.

The

LMH6514

operates

over

the

industrial

temperature range of

−40°C to +85°C. The LMH6514

is available in a 16-Pin, thermally enhanced, WQFN

package.

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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

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All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 2008, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.