Overview

Features and Benefits

  • Wide VIN Range: 4.5V to 38V, VOUT: 0.6V to 5.5V
  • ±0.67% Output Voltage Accuracy Over Temperature, Differential Output Voltage Sensing, Allowing Up to ±500mV Line Loss at Remote Ground on Channel 1
  • ±1% Output on the Independent 2nd Channel
  • Controlled On-Time, Valley Current Mode Control
  • Fast Load Transient Response
  • Detect Transient (DTR) Reduces VOUT Overshoot
  • Frequency Programmable from 200kHz to 2MHz, Synchronizable to External Clock
  • tON(MIN) = 30ns, tOFF(MIN) = 90ns
  • RSENSE or Inductor DCR Current Sensing
  • Overvoltage Protection and Current Limit Foldback
  • Power Good Output Voltage Monitor
  • Output Voltage Tracking and Adjustable Soft Start-Up
  • Thermally Enhanced 38-Pin (5mm × 7mm) QFN and TSSOP packages

Product Details

The LTC3838 is a dual, PolyPhase® synchronous step-down DC/DC switching regulator controller. Two independent channels drive all N-channel power MOSFETs. The controlled on-time, valley current mode control architecture allows for fast transient response and constant frequency switching in steady-state operation, independent of VIN, VOUT and load current. Its load-release transient detection feature significantly reduces overshoot at low output voltages.

Differential output voltage sensing, along with a precision internal reference, offers an accurate ±0.67% output regulation on Channel 1, even if the remote output ground deviates from local ground by ±500mV. The second channel can either provide an independent ±1% output, or together with the first channel of this controller, serve as one of the PolyPhase channels for a single-output voltage.

The switching frequency can be programmed from 200kHz to 2MHz with an external resistor, and can be synchronized to an external clock. Very low tON and tOFF times allow for near 0% and near 100% duty cycles, respectively. Voltage tracking soft start-up and multiple safety features are provided.

See below for a comparison of LTC3838, LTC3838-1 and LTC3838-2.

Part Number Description
LTC3838   ±0.67% Differential Output Voltage Accuracy Over Temperature on Channel 1, ±1% Output Regulation on Channel 2, Separate Per Channel 30mV to 100mV Current Sense Range Controls
LTC3838-1   ±0.67% Differential Output Voltage Accuracy Over Temperature on Both Channel 1 and Channel 2, Single Pin 30mV/60mV Current Sense Range Controls
LTC3838-2 ±0.67% Differential Output Voltage Accuracy With Internal Reference on Channel 1, ±4mV Differential with External Reference Voltage on Channel 2, Fixed 30mV Current Sense Range

Applications

  • Distributed Power Systems
  • Point-of-Load Converters
  • Computing Systems
  • Data Communication Systems

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (4)

Tools & Simulations

LTspice

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.

To launch ready-to-run LTspice demonstration circuits for this part:

Step 1: Download and install LTspice on your computer.

Step 2: Click on the link in the section below to download a demonstration circuit.

Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.

LTspice

Models for the following parts are available in LTspice:

LTC3838
LTC3838-1
LTC3838-2

LTpowerCAD

LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.

To open the project file for this circuit:

Step 1: Download and install LTpowerCAD on your computer.

Step 2: Click on the link(s) in the section below to download part-specific project files.

Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.

LTPowerCAD

Design tools for the following parts are available in LTpowerCAD:

LTC3838
LTC3838 Parallel
LTC3838-2
ltc3838Parallel

Product Recommendations

LTC3838 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.

Discussions

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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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


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Evaluation Boards Pricing displayed is based on 1-piece.
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.