Analog Devices LT3935

Description

The LT®3935 is a monolithic, synchronous, step-down DC/DC converter that utilizes fixed-frequency, peak current control and provides PWM dimming for a string of LEDs. The LED current is programmed by an analog voltage or the duty cycle of pulses at the CTRL pin. An output voltage limit can be set with a resistor divider to the FB pin.The switching frequency is programmable from 200kHz to 2MHz by an external resistor at the RT pin or by an external clock at the SYNC/SPRD pin. With the optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI. Additional features include an LED current monitor, an accurate EN/UVLO pin threshold, open-drain fault reporting for open-circuit and short-circuit load conditions,and thermal shutdown. The LT3935 utilizes proprietary Silent Switcher technology for very low EMI.

Features

• ±1.5% LED Current Regulation
• ±1.2% Output Voltage Regulation
• Spread-Spectrum Frequency Modulation
• Silent Switcher® Architecture for Low EMI
• 3.6V to 36V Input Voltage Range
• 0V to 36V LED String Voltage
• 200kHz to 2MHz with SYNC Function
• 20:1 Analog or Duty Cycle LED Current Control
• Open/Short LED Fault Indication
• Accurate LED Current Sense with Monitor Output
• Programmable UVLO
• Thermally Enhanced 28-Lead (5mm × 4mm) LQFN

Typical applications

• Industrial and General Purpose Lighting
• Automotive Lighting

More information

• Datasheet
• IC product information