LTC3815 - 6A Monolithic Synchronous DC/DC Step-Down Converter with Digital Power System Management


  • 2.25V to 5.5V Input Voltage Range
  • ±1% Total Output Voltage Accuracy Over Temperature at VIN = 3.3V or 5V
  • Single Resistor-Programmable Output Voltage
  • PMBus Compliant Serial Interface:
    Programmable Output Voltage Margining: Up to ±25% VOUT Range with 0.1% Resolution
    Read back of Average and Peak Temperature, Current, and Voltage (25Hz Refresh Rate)
    Fault Status
  • Phase-Lockable Fixed Frequency Up to 3MHz
  • Less Than 1ms Power-Up Time
  • Integrated 13-Bit ADC
  • Optional External Reference Input
  • Pin Selectable Fast-Margining of the Output Voltage
  • Power Good Flag with Pin Programmable Thresholds and Filter Delay
  • Differential Remote Output Voltage Sensing
  • Master Shutdown Mode: <1μA Supply Current
  • Clock Out for 2-Phase Operation (12A Output Current)
  • Available in a Thermally-Enhanced 38-Lead 4mm × 6mm QFN Package
  • Download LTpowerPlay Software

Typical Application

LTC3815 Typical Application
LTC3815 Typical Application


The LTC®3815 is a high efficiency, 6A monolithic synchronous buck regulator using a phase lockable controlled on-time, current mode architecture. The output voltage is programmable from 0.4V to 72% of VIN with a single external resistor or an external voltage reference through the reference input (REF) pin. The output voltage can be margined up or down up to ±25% with 0.1% resolution via a PMBus-compliant serial interface. The serial interface can also be used to read back fault status and both timeaveraged (~4ms) and peak input/output current, input/ output voltage and temperature. System configuration and monitoring is supported by the LTpowerPlay® development system.

The architecture provides extremely fast transient response and allows operation at the very low on-times required to regulate low output voltages at high switching frequencies. The operating frequency is programmable from 400kHz to 3MHz with an external resistor or for noise sensitive applications, it can be synchronized to an external clock over the same range. The operating supply voltage range is from 2.25V to 5.5V making it suitable for operation from 2.5V, 3.3V or 5V rails or Lithium-Ion batteries.


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

Part Number Package Code Temp Package
LTC3815EUFE#PBF 4x6 QFN-38 UFE E 05-08-1750 Yes
LTC3815EUFE#TRPBF 4x6 QFN-38 UFE E 05-08-1750 Yes
LTC3815IUFE#PBF 4x6 QFN-38 UFE I 05-08-1750 Yes
LTC3815IUFE#TRPBF 4x6 QFN-38 UFE I 05-08-1750 Yes

LTC3815 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
LTC3815EUFE#PBF 4x6 QFN-38 E $6.73 $4.71 Yes
LTC3815EUFE#TRPBF 4x6 QFN-38 E $4.77 Yes
LTC3815IUFE#PBF 4x6 QFN-38 I $7.40 $5.18 Yes
LTC3815IUFE#TRPBF 4x6 QFN-38 I $5.24 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
DC2065A LTC3815EUFE Demo Board | PMBus Buck, 2.25V ≤ VIN ≤ 5.5V; VOUT Range: 0.4 V to 0.72VIN @ 6A Contact Factory
Buy Now
Click here to view our complete list of demo boards


  • Intelligent Energy Efficient Power Conversion
  • ASIC/FPGA/Processor Power
  • Distributed Power Systems
  • Point of Load Power Conversion

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