LTC6603 - Dual Adjustable Lowpass Filter


  • Guaranteed Phase and Gain Matching Specs
  • Programmable BW Up to 2.5MHz
  • Programmable Gain (0dB/6dB/12dB/24dB)
  • 9th Order Linear Phase Response
  • Differential, Rail-to-Rail Inputs and Outputs
  • Low Noise: –145dBm/Hz (Input Referred)
  • Low Distortion: –75dBc at 200kHz
  • Simple Pin Programming or SPI Interface
  • Set the Max Speed/Power with an External R
  • Operates from 2.7V to 3.6V
  • Input Range from 0V to 5.5V
  • 4mm × 4mm QFN Package

Typical Application

LTC6603 Typical Application
LTC6603 Typical Application


The LTC6603 is a dual, matched, programmable lowpass filter for communications receivers and transmitters. The selectivity of the LTC6603, combined with its linear phase, phase matching and dynamic range, make it suitable for filtering in many communications systems. With 1.5° phase matching between channels, the LTC6603 can be used in applications requiring pairs of matched filters, such as transceiver I and Q channels. Furthermore, the differential inputs and outputs provide a simple interface for most communications systems.

The sampled data filter does not require an external clock yet its cutoff frequency can be set with a single external resistor with an accuracy of 3.5% or better. The external resistor programs an internal oscillator whose frequency is divided prior to being applied to the filter networks. This allows up to three cutoff frequencies that can be obtained for each external resistor value, allowing the cutoff frequency to be programmed over a range of more than six octaves. Alternatively, the cutoff frequency can be set with an external clock. The filter gain can also be programmed to 1, 2, 4 or 16.

The LTC6603 features a low power shutdown mode that can be programmed through the serial interface and is available in a 24-pin 4mm × 4mm QFN package.


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
LTC6603CUF#PBF 4x4 QFN-24 UF C 05-08-1697 Yes
LTC6603CUF#TRPBF 4x4 QFN-24 UF C 05-08-1697 Yes
LTC6603IUF#PBF 4x4 QFN-24 UF I 05-08-1697 Yes
LTC6603IUF#TRPBF 4x4 QFN-24 UF I 05-08-1697 Yes

LTC6603 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
LTC6603CUF#PBF 4x4 QFN-24 C $10.50 $7.50 Yes
LTC6603CUF#TRPBF 4x4 QFN-24 C $7.55 Yes
LTC6603IUF#PBF 4x4 QFN-24 I $12.29 $8.60 Yes
LTC6603IUF#TRPBF 4x4 QFN-24 I $8.65 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
DC1304A-B LTC6603 Demo Board | Dual Programmable 2.5MHz Filter / ADC Driver $125.00
Buy Now
Click here to view our complete list of demo boards


  • Small/Low Cost Basestations:
  • Low Cost Repeaters, Radio Links, and Modems
  • 802.11x Receivers
  • JTRS

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