LTC3866 - Current Mode Synchronous Controller for Sub Milliohm DCR Sensing


  • Sub Milliohm DCR Current Sensing
  • High Efficiency: Up to 95%
  • Selectable Current Sensing Limit
  • Programmable DCR Temperature Compensation
  • Die Overtemperature Thermal Shutdown
  • ± 0.5% 0.6V Output Voltage Accuracy
  • Programmable Fixed Frequency 250kHz to 770kHz
  • High Speed Differential Remote Sense Amplifier
  • Wide Input Voltage Range: 4.5V to 38V
  • Output Voltage Range: 0.6V to 3.5V with Diffamp
  • Adjustable Soft-Start or Output Voltage Tracking
  • Foldback Output Current Limit
  • Short-Circuit Soft Recovery
  • Output Overvoltage Protection
  • 24-Lead (4mm × 4mm) QFN and 24-Lead FE Packages

Typical Application

LTC3866 Typical Application
LTC3866 Typical Application


The LTC®3866 is a single phase current mode synchronous step-down switching regulator controller that drives all N-channel power MOSFET switches. It employs a unique architecture which enhances the signal-to-noise ratio of the current sense signal, allowing the use of a very low DC resistance power inductor to maximize the efficiency in high current applications. This feature also reduces the switching jitter commonly found in low DCR applications. The LTC3866 also includes a high speed remote sense differential amplifier, a programmable current sense limit that can be selected to 10mV, 15mV, 20mV, 25mV or 30mV, and DCR temperature compensation to limit the maximum output current precisely over temperature.

The LTC3866 also features a precise 0.6V reference with a guaranteed limit of ±0.5% that provides an accurate output voltage from 0.6V to 3.5V. A 4.5V to 38V input voltage range allows it to support a wide variety of bus voltages and various types of batteries.

The LTC3866 is offered in a low profile 24-lead 4mm × 4mm QFN and 24-lead exposed pad FE packages.


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
LTC3866EFE#PBF TSSOP-24 FE E 05-08-1771 Yes
LTC3866EFE#TRPBF TSSOP-24 FE E 05-08-1771 Yes
LTC3866EUF#PBF 4x4 QFN-24 UF E 05-08-1697 Yes
LTC3866EUF#TRPBF 4x4 QFN-24 UF E 05-08-1697 Yes
LTC3866IFE#PBF TSSOP-24 FE I 05-08-1771 Yes
LTC3866IFE#TRPBF TSSOP-24 FE I 05-08-1771 Yes
LTC3866IUF#PBF 4x4 QFN-24 UF I 05-08-1697 Yes
LTC3866IUF#TRPBF 4x4 QFN-24 UF I 05-08-1697 Yes

LTC3866 Package Drawing
LTC3866 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
LTC3866EFE#PBF TSSOP-24 E $4.26 $2.98 Yes
LTC3866EFE#TRPBF TSSOP-24 E $3.04 Yes
LTC3866EUF#PBF 4x4 QFN-24 E $3.87 $2.71 Yes
LTC3866EUF#TRPBF 4x4 QFN-24 E $2.77 Yes
LTC3866IFE#PBF TSSOP-24 I $4.96 $3.47 Yes
LTC3866IFE#TRPBF TSSOP-24 I $3.53 Yes
LTC3866IUF#PBF 4x4 QFN-24 I $4.26 $2.98 Yes
LTC3866IUF#TRPBF 4x4 QFN-24 I $3.04 Yes
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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 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
DC1829A LTC3866EUF Demo Board VIN = 4.5V to 14V, VOUT = 1.5V @ 30A $150.00
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Design Tools


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