Features and Benefits

  • Dual Low Dropout Linear Tracking Regulators
    • 200mA Outputs with Programmable Current Limits
    • 1.6V to 45V Input Range
    • Fault Protected to ±45V
  • Triple Output Supply from a Single Input Requires Only One Inductor
  • IQ = 50μA at 12VIN to 6V and 5V with No Load
  • Buck Regulator:
    • Low Ripple (<15mVP-P) Burst Mode® Operation
    • 400mA Output with Internal Power Switch
    • 4.3V to 40V Input Operation Range (60V Max)
  • Adjustable 250kHz to 2.2MHz Switching Frequency
  • Power Good Indicator
  • Available in a Thermally-Enhanced 16-Lead MSOP Package

Product Details

The LT3668 is a monolithic triple power supply composed of a 400mA buck switching regulator and two 200mA low dropout linear tracking regulators (LDOs).This provides a complete and robust power solution for applications that require the power supply of a sensor to tightly track the power supply of a measurement ASIC.

Each tracking LDO supplies 200mA of output current with a typical dropout voltage of 340mV, and each LDO has an accurate resistor programmable current limit.

Internal protection circuitry includes reverse-battery protection, current limiting, thermal limiting and reverse current protection.

The buck regulator includes a high efficiency switch, a boost diode, and the necessary oscillator, control and logic circuitry. Current mode topology is used for fast transient response and good loop stability. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15mV in a typical application.

The LT3668 is available in a thermally-enhanced 16-lead MSOP package with exposed pad for low thermal resistance.


  • Fault-Protected Sensor Supply
  • Automotive and Industrial Supplies
  • Power for Portable Instrumentation

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Evaluation Kits (1)

Tools & Simulations


LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.


Models for the following parts are available in LTspice:


Product Recommendations

LT3668 Companion Parts

Recommended Related Parts

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

PCN-PDN Information

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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.