Analog Devices LT3942

Description

The LT®3942 is a monolithic 4-switch synchronous buck-boost LED driver. The driver can regulate the LED string current up to 34V with input voltages above, below, or equal to the output voltage. The proprietary peak-buck peak-boost current mode control scheme allows adjustable and synchronizable 300kHz to 2MHz fixed frequency operation, or internal 25% triangle spread spectrum operation for low EMI. With 3V to 36V input, 0V to 36V output and seamless low-noise transitions between operation regions, the LT3942 is ideal for LED driver applications in automotive, industrial and battery-powered systems.The LT3942 provides LED current regulation with up to 128:1 internal and 5000:1 external PWM dimming using an optional high-side PMOS switch. The CTRL pin provides flexible 20:1 analog dimming with ±2.5% LED current regulation at 100mV full scale. Robust fault protection detects an open or short LED condition, during which the LT3942 retries, latches off, or keeps running.

Features

• 4-Switch Single Inductor Architecture Allows VIN Above, Below or Equal to VOUT
• Proprietary Peak-Buck Peak-Boost Current Mode
• 3V to 36V Input Voltage Range
• 0V to 36V Output Voltage Range
• ±1.5% Output Voltage Regulation
• ±3% LED Current Regulation
• 5000:1 External and 128:1 Internal PWM Dimming
• Rail-to-Rail LED Current Sense and Monitor Output
• Open and Short LED Protection with Fault Reporting
• 300kHz to 2MHz Fixed Switching Frequency with External Frequency Synchronization
• Flicker-Free Spread Spectrum for Low EMI
• Available in 28-Lead QFN (4mm × 5mm)

Typical applications

• General Purpose LED Driver / Automotive and Industrial Lighting
• Voltage Regulator with Accurate Current Limit

More information

• Datasheet
• IC product information