LT1568 - Very Low Noise, High Frequency Active RC, Filter Building Block

Features

  • Up to 10MHz Center Frequency on a Single 3V Supply
  • Easy to Use—A Single Resistor Value Sets Lowpass Cutoff Frequency (200kHz <= f C <= 5MHz)
  • Unequal Resistor Values Extend Cutoff Frequency Up to 10MHz
  • Extremely Flexible—Different Resistor Values Allow Lowpass Transfer Functions with or Without Gain
  • SNR = 92dB (fC = 2MHz, 2VP-P)
  • THD = –84dB (fC = 2MHz, 1VP-P)
  • Internal Capacitors Trimmed to ±0.75%
  • Single 4-Pole Lowpass Filter or Matched Pair of 2-Pole Lowpass Filters
  • Can be Connected as a Bandpass Filter
  • Single-Ended or Differential Output
  • Operates from Single 3V (2.7V Min) to ±5V Supply
  • Rail-to-Rail Input and Output Voltages

Typical Application

LT1568 Typical Application
LT1568 Typical Application

Description

The LT1568 is an easy-to-use, active-RC filter building block with rail-to-rail inputs and outputs. The internal capacitors of the IC and the GBW product of the internal low noise op amps are trimmed such that consistent and repeatable filter responses can be achieved. With a single resistor value, the LT1568 provides a pair of matched 2-pole Butterworth lowpass filters with unity gain suitable for I/Q channels.

By using unequal-valued external resistors, the two 2-pole sections can create different frequency responses or gains. In addition, the two stages may be cascaded to create a single 4-pole filter with a programmable response. Capable of cutoff frequencies up to 10MHz, the LT1568 is ideal for antialiasing or channel filtering in high speed data communications systems. The LT1568 can also be used as a bandpass filter.

The LT1568 features very low noise, supporting signal-to-noise ratios of over 90dB. It also provides single-ended to differential signal conversion for directly driving high speed A/D converters. The LT1568 has a shutdown mode that reduces supply current to approximately 0.5mA on a 5V supply.

The LT1568 is available in a narrow 16-lead SSOP package.

Packaging

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

SSOP-16

LT1568 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LT1568CGN SSOP 16 C $5.20 $4.25 View
LT1568CGN#PBF SSOP 16 C $5.20 $4.25 View
LT1568CGN#TR SSOP 16 C $4.31 View
LT1568CGN#TRPBF SSOP 16 C $4.31 View
LT1568IGN SSOP 16 I $6.20 $5.10 View
LT1568IGN#PBF SSOP 16 I $6.20 $5.10 View
LT1568IGN#TR SSOP 16 I $5.16 View
LT1568IGN#TRPBF SSOP 16 I $5.16 View
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
DC675A-A LT1568CGN | Active RC Filter Building Block, (200kHz to 10MHz), Universal Filter $50.00
DC675A-C LT1568CGN | Use DC675A-A and modify per Quick Start Guide Contact Factory
DC675A-D LT1568CGN | Use DC675A-A and modify per Quick Start Guide Contact Factory
Buy Now
Click here to view our complete list of demo boards

Applications

  • Replaces Discrete RC Active Filters and LC Filter Modules
  • Antialiasing/Reconstruction Filters
  • Dual or I-and-Q Channels (Two Matched 2nd Order Filters in One Package)
  • Single-Ended to Differential Conversion
  • Video Signal Processing

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 mylinear@linear.com with questions and comments.

Simulate

LTspice IV is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. To download LTspice IV and other FREE simulation tools, please visit our Design Simulation page.

Related models available in LTspice IV
LT1568

The LT1568 is a dual amplifier block useful for creating high frequency active filters. Implementation of lowpass and bandpass filters over a frequency range of 100KHz to 10MHz can be achieved using only a few external resistors. This easy to use Excel based Design Guide crunches the numbers to calculate all of the external component values and provides a 'ready to build' schematic of the filter.

Technical Support