LTC3838 - Dual, Fast, Accurate Step- Down DC/DC Controller with Differential Output Sensing


  • 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

Typical Application

LTC3838 Typical Application
LTC3838 Typical Application


The LTC®3838 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.

Part NumberDescription
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


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
LTC3838EFE#PBF TSSOP-38 FE E 05-08-1772 Yes
LTC3838EFE#TRPBF TSSOP-38 FE E 05-08-1772 Yes
LTC3838EUHF#PBF 5x7 QFN-38 UHF E 05-08-1701 Yes
LTC3838EUHF#TRPBF 5x7 QFN-38 UHF E 05-08-1701 Yes
LTC3838IFE#PBF TSSOP-38 FE I 05-08-1772 Yes
LTC3838IFE#TRPBF TSSOP-38 FE I 05-08-1772 Yes
LTC3838IUHF#PBF 5x7 QFN-38 UHF I 05-08-1701 Yes
LTC3838IUHF#TRPBF 5x7 QFN-38 UHF I 05-08-1701 Yes

LTC3838 Package Drawing
LTC3838 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
LTC3838EFE#PBF TSSOP-38 E $4.86 $3.40 Yes
LTC3838EFE#TRPBF TSSOP-38 E $3.46 Yes
LTC3838EUHF#PBF 5x7 QFN-38 E $4.54 $3.18 Yes
LTC3838EUHF#TRPBF 5x7 QFN-38 E $3.24 Yes
LTC3838IFE#PBF TSSOP-38 I $5.54 $3.88 Yes
LTC3838IFE#TRPBF TSSOP-38 I $3.94 Yes
LTC3838IUHF#PBF 5x7 QFN-38 I $5.13 $3.59 Yes
LTC3838IUHF#TRPBF 5x7 QFN-38 I $3.65 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
DC1626A-A LTC3838EFE Demo Board (DCR Sense) | 4.5V ≤ VIN ≤ 26V; VOUT1 = 1.2V @ 15A, VOUT2 = 1.5V @ 15A $150.00
DC1626A-B LTC3838EFE Demo Board (RSENSE) |4.5V ≤ VIN ≤ 26V; VOUT1 = 1.2V @ 15A, VOUT2 = 1.5V @ 15A $150.00
DC1801A-A LTC3838EUHF Demo Board (DCR Sense) | VIN = 4.5V to 14V, VOUT1 = 1.2V @ 20A, VOUT2 = 1.5V @ 20A $150.00
DC1801A-B LTC3838EUHF Demo Board (RSENSE) | VIN = 4.5V to 14V, VOUT1 = 1.2V @ 20A, VOUT2 = 1.5V @ 20A $150.00
Buy Now
Click here to view our complete list of demo boards


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

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


LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:


The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

To open the project file for this circuit:

Design tools for the following parts are available in LTpowerCAD:
LTC3838 Parallel

Technical Support