ISSI IS32LT3957 | Demoboard IS32LT3957-ZLA3-EBSEPIC

Description

The IS32LT3957/IS31LT3957 is a current mode PWM controller designed to drive a low side external NMOS FET for wide input/output voltage range and high LED current applications. An external resistor senses the high side output current of the LED string. A high side sense is the most flexible current sensing scheme, since it functions in either boost or buck-boost mode configurations. The controller can be configured with an external resistor to operate between 100kHz~1MHz frequency resulting in small external inductor and capacitors while maintaining high efficiency. A singlecapacitor is all that is required to set the spread spectrum dither frequency to reduce the radiated peak emission and optimize the system EMI performance.

Features

• Wide high voltage input range: 5V to 75V
• Supports boost, buck-boost, SEPIC and buck topology
• ±3.5% output current accuracy over -40°C ~ +125°C temperature
• Adjustable operating frequency range of 100kHz~1MHz
• Programmable soft start to avoid inrush current
• Fixed under voltage lockout threshold
• EMI reduction capabilities
• Programmable spread spectrum function
• Operating frequency synchronization with external clock source
• Supports either analog or PWM dimming
• Fault protection with reporting:
• VCC under voltage lockout (not reported)
• Programmable output over voltage protection
• Output short circuit protection
• RT/SYNC pin short protection
• VDD pin short protection
• VDD under voltage lockout (not reported)
• Over temperature protection
• AEC-Q100 Qualified (IS32LT3957 only)

Typical applications

• 9V~16V, 6A DC power supply
• LED load (7~10 LEDs in series/1A)

More information

• Datasheet
• IC product information