LT8391A - 60V 2MHz Synchronous 4-Switch Buck-Boost LED Driver Controller


  • 4-Switch Single Inductor Architecture Allows VIN Above, Below or Equal to VOUT
  • Up to 95% Efficiency at 2MHz
  • Proprietary Peak-Buck Peak-Boost Current Mode
  • Wide VIN Range: 4V to 60V
  • Wide VOUT Range: 0V to 60V (51V LED)
  • ±3% LED Current Accuracy
  • 2000:1 External and 128:1 Internal PWM Dimming
  • High Side PMOS PWM Switch Driver
  • No Top MOSFET Refresh Noise in Buck or Boost
  • Adjustable and Synchronizable: 600kHz to 2MHz
  • Flicker-Free Spread Spectrum for Low EMI
  • Open and Short LED Protection with Fault Reporting
  • Available in 28-Lead TSSOP with Exposed Pad and 28-Lead QFN (4mm × 5mm)

Typical Application

LT8391A Typical Application
LT8391A Typical Application


The LT®8391A 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 600kHz to 2MHz fixed frequency operation, or internal 25% 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 LT8391A is ideal for LED driver and battery charger applications in automotive, industrial, and battery-powered systems.

The LT8391A 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 LT8391A retries, latches off, or keeps running.

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


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

Part Number Package Code Temp Package
LT8391AEFE#PBF TSSOP-28 FE E 05-08-1663 (EB) Yes
LT8391AEFE#TRPBF TSSOP-28 FE E 05-08-1663 (EB) Yes
LT8391AEUFD#PBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LT8391AEUFD#TRPBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LT8391AHFE#PBF TSSOP-28 FE H 05-08-1663 (EB) Yes
LT8391AHFE#TRPBF TSSOP-28 FE H 05-08-1663 (EB) Yes
LT8391AHUFD#PBF 4x5 QFN-28 UFD H 05-08-1712 Yes
LT8391AHUFD#TRPBF 4x5 QFN-28 UFD H 05-08-1712 Yes
LT8391AIFE#PBF TSSOP-28 FE I 05-08-1663 (EB) Yes
LT8391AIFE#TRPBF TSSOP-28 FE I 05-08-1663 (EB) Yes
LT8391AIUFD#PBF 4x5 QFN-28 UFD I 05-08-1712 Yes
LT8391AIUFD#TRPBF 4x5 QFN-28 UFD I 05-08-1712 Yes

LT8391A Package Drawing
LT8391A 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
LT8391AEFE#PBF TSSOP-28 E $6.64 $4.65 Yes
LT8391AEFE#TRPBF TSSOP-28 E $6.70 $4.71 Yes
LT8391AEUFD#PBF 4x5 QFN-28 E $6.64 $4.65 Yes
LT8391AEUFD#TRPBF 4x5 QFN-28 E $6.70 $4.71 Yes
LT8391AHFE#PBF TSSOP-28 H $7.67 $5.37 Yes
LT8391AHFE#TRPBF TSSOP-28 H $7.73 $5.43 Yes
LT8391AHUFD#PBF 4x5 QFN-28 H $7.67 $5.37 Yes
LT8391AHUFD#TRPBF 4x5 QFN-28 H $7.73 $5.43 Yes
LT8391AIFE#PBF TSSOP-28 I $7.31 $5.12 Yes
LT8391AIFE#TRPBF TSSOP-28 I $7.37 $5.18 Yes
LT8391AIUFD#PBF 4x5 QFN-28 I $7.31 $5.12 Yes
LT8391AIUFD#TRPBF 4x5 QFN-28 I $7.37 $5.18 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
DC2575A LT8391AIFE Demo Board | 60V, 2MHz Synchronous Buck-Boost LED Driver Controller Contact Factory
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Click here to view our complete list of demo boards


  • Automotive Head Lamps/Running Lamps
  • High Frequency LED Lighting

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