LTC6431-20 - 20dB Gain Block, 50Ω IF Amplifier


  • 50Ω Matched 20MHz to 1400MHz
  • 20.8dB Power Gain
  • 46.2dBm OIP3 at 240MHz Into 50Ω
  • NF = 2.6dB at 240MHz
  • 0.6nV/√Hz Total Input Noise
  • S11 < –10dB Up to 2.0GHz
  • S22 < –10dB Up to 1.4GHz
  • >2.0VP-P Linear Output Swing
  • P1dB = 22.0dBm
  • 50Ω Single-Ended Input/Output
  • Insensitive to VCC Variation
  • A-Grade 100% OIP3 Tested at 240MHz
  • Input/Output Internally Matched to 50Ω
  • Single 5V Supply

Typical Application

LTC6431-20 Typical Application
LTC6431-20 Typical Application


The LTC®6431-20 is a gain block amplifier exhibiting excellent linearity at frequencies beyond 1000MHz and with low associated output noise.

The unique combination of linearity, low noise and low power dissipation make this an ideal candidate for many signal-chain applications. The LTC6431-20 is easy to use, requiring a minimum of external components. It is internally input/output matched to 50Ω and it draws only 93mA from a single 5V supply.

On-chip bias and temperature compensation maintain performance over environmental changes.

The LTC6431-20 uses a high performance SiGe BiCMOS process for excellent repeatability compared with similar GaAs amplifiers. All A-grade LTC6431-20 devices are tested and guaranteed for OIP3 at 240MHz. The LTC6431-20 is housed in a 4mm × 4mm 24-lead QFN package with an exposed pad for thermal management and low inductance.


CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
LTC6431AIUF-20#PBF 4x4 QFN-24 UF I 05-08-1697 Yes
LTC6431AIUF-20#TRPBF 4x4 QFN-24 UF I 05-08-1697 Yes
LTC6431BIUF-20#PBF 4x4 QFN-24 UF I 05-08-1697 Yes
LTC6431BIUF-20#TRPBF 4x4 QFN-24 UF I 05-08-1697 Yes

LTC6431-20 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
LTC6431AIUF-20#PBF 4x4 QFN-24 I $6.99 $4.89 Yes
LTC6431AIUF-20#TRPBF 4x4 QFN-24 I $4.95 Yes
LTC6431BIUF-20#PBF 4x4 QFN-24 I $2.70 $1.89 Yes
LTC6431BIUF-20#TRPBF 4x4 QFN-24 I $1.95 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC2077A LTC6431-20 Demoboard 50ohm, 20dB Gain Block Demo Board $150.00
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Click here to view our complete list of demo boards


  • Single-Ended IF Amplifier
  • ADC Driver
  • CATV

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Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
  • LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
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