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Features and Benefits
- 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)
The LT8391A 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+|
- Automotive Head Lamps/Running Lamps
- High Frequency LED Lighting
Product Lifecycle 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 (1)
Demonstration circuit DC2575A is a 60V 2MHz synchronous buck-boost LED driver featuring the LT8391A. It accepts an input voltage from 4V to 60V and drives a single string of LEDs up to 16V at 1.5A. DC2575A runs at 2MHz switching frequency without spread spectrum, but spread spectrum frequency modulation (SSFM) can be enabled with a simple jumper. SSFM spreads the switching frequency from fSW to fSW + 25% for reduced EMI.
Tools & Simulations
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.
Models for the following parts are available in LTspice:
Technical Articles (1)
Analog Dialogue (1)
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.
Sample & Buy
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.