LT5538 - 40MHz to 3.8GHz RF Power Detector with 75dB Dynamic Range


  • Frequency Range: 40MHz to 3.8GHz
  • 75dB Log Linear Dynamic Range
  • Exceptional Accuracy over Temperature
  • Linear DC Output vs. Input Power in dBm
  • -72dBm Detection Sensitivity
  • Single-ended RF Input
  • Low Supply Current: 29mA
  • Supply Voltage: 3V to 5.25V
  • 8-lead DFN 3mm × 3mm package

Typical Application

LT5538 Typical Application
LT5538 Typical Application


The LT5538 is a 40MHz to 3800MHz monolithic logarithmic RF power detector, capable of measuring RF signals over a wide dynamic range, from -75dBm to 10dBm. The RF signal in an equivalent decibel-scaled value is precisely converted into DC voltage on a linear scale. The wide linear dynamic range is achieved by measuring the RF signal using cascaded RF limiters and RF detectors. Their outputs are summed to generate an accurate linear DC voltage proportional to the input RF signal in dBm. The LT5538 delivers superior temperature stable output (within ±1dB over full temperature range) from 40MHz to 3.8GHz. The output is buffered with a low impedance driver.


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
LT5538IDD#PBF 3x3 DFN-8 DD I 05-08-1698 Yes
LT5538IDD#TRPBF 3x3 DFN-8 DD I 05-08-1698 Yes

LT5538 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
LT5538IDD#PBF 3x3 DFN-8 I $6.40 $4.50 Yes
LT5538IDD#TRPBF 3x3 DFN-8 I $4.55 Yes
Buy NowRequest Samples
* 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
DC1120A LT5538IDD | 40MHz to 3.8GHz 75dB Dynamic Range Log Detector. Board optimized for 40MHz to 2.7GHz. Call Factory for higher freq. $100.00
Buy Now
Click here to view our complete list of demo boards


  • Received Signal Strength Indication (RSSI)
  • RF Power Measurement and Control
  • RF/IF Power Detection
  • Receiver RF/IF Gain Control
  • Envelope Detection
  • ASK Receiver

Product Notifications

Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.

Forgot your password? Click here.
Need help? Email with questions and comments.

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
  • And More!

Technical Support