LT8391 - 60V Synchronous 4-Switch Buck-Boost LED Controller with Spread Spectrum
Datasheet Documentation
Design Note
LT Journal
Press Release


Typical Application

LT8391 Typical Application
LT8391 Typical Application


The LT®8391 is a synchronous 4-switch buck-boost LED controller that regulates LED current from input voltage above, below, or equal to the output voltage. The proprietary peak-buck peak-boost current mode control scheme allows adjustable and synchronizable 150kHz to 650kHz fixed frequency operation, or internal ±15% triangle spread spectrum operation for low EMI. With 4V to 60V input, 0V to 60V output, and seamless low noise transitions between operation regions, the LT8391 is ideal for LED driver and battery charger applications in automotive, industrial, and battery-powered systems.

The LT8391 provides both internal (up to 128:1) and external (up to 2000:1) LED current PWM dimming with a high-side PMOS switch. Two CTRL pins provide flexible 20:1 analog dimming with ±3% LED current accuracy at 100mV full scale. Fault protection is provided to detect an open or short LED condition, during which the LT8391 retries, latches off, or keeps running.

  Switching Frequency Max Output Power
LT8391 Adjustable 150kHz - 650kHz 450W+
LT8391A 2MHz 50W+

4x5 QFN-28,TSSOP-28

LT8391 Package Drawing
LT8391 Package Drawing
Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price
LT8391EFE#PBF TSSOP 28 E $6.64 $4.65
LT8391HUFD#PBF QFN 28 H $7.67 $5.37
LT8391IUFD#TRPBF QFN 28 I $7.37 $5.18
LT8391IFE#TRPBF TSSOP 28 I $7.37 $5.18
LT8391EUFD#PBF QFN 28 E $6.64 $4.65
LT8391EUFD#TRPBF QFN 28 E $6.70 $4.71
LT8391AIFE#TRPBF TSSOP 28 I $7.37 $5.18
LT8391AIUFD#TRPBF QFN 28 I $7.37 $5.18
LT8391AHFE#PBF TSSOP 28 H $7.67 $5.37
LT8391AHUFD#PBF QFN 28 H $7.67 $5.37
LT8391AEUFD#TRPBF QFN 28 E $6.70 $4.71
LT8391AIFE#PBF TSSOP 28 I $7.31 $5.12
LT8391AEFE#PBF TSSOP 28 E $6.64 $4.65
LT8391AEFE#TRPBF TSSOP 28 E $6.70 $4.71
LT8391AHFE#TRPBF TSSOP 28 H $7.73 $5.43
LT8391IUFD#PBF QFN 28 I $7.31 $5.12
LT8391IFE#PBF TSSOP 28 I $7.31 $5.12
LT8391EFE#TRPBF TSSOP 28 E $6.70 $4.71
LT8391AEUFD#PBF QFN 28 E $6.64 $4.65
LT8391AIUFD#PBF QFN 28 I $7.31 $5.12
LT8391AHUFD#TRPBF QFN 28 H $7.73 $5.43
LT8391HFE#TRPBF TSSOP 28 H $7.73 $5.43
LT8391HUFD#TRPBF QFN 28 H $7.73 $5.43
LT8391HFE#PBF TSSOP 28 H $7.67 $5.37
* 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
DC2345A LT8391EFE Demo Board | Sync Buck-Boost LED Driver, 4V ≤ VIN ≤ 60V, VLED = 25V @ 2A $309.00