Automotive LED controller with flexible topology
The Analog Devices LT3755EMSE-1#WPBF is a DC DC controller designed for driving high-power LEDs, qualified to AEC-Q100 for automotive applications. It operates as a constant-current, constant-voltage controller supporting buck, boost, SEPIC, and flyback topologies — a single part number that can handle multiple LED string configurations from a 4.5 V to 40 V supply rail. The controller drives an external N-channel MOSFET (no internal switch), so the output current is set by the external pass element and sense resistor, not limited by the IC package.
Switching frequency and dimming flexibility
The switching frequency is programmable from 100 kHz to 1 MHz via a single resistor, letting you trade inductor size against switching losses. For a compact automotive headlamp module, running at 1 MHz shrinks the magnetics; for a high-efficiency daytime-running-light design, 300 kHz cuts gate-drive losses. Dimming is supported in both analog and PWM modes — analog dimming adjusts the LED current linearly, while PWM dimming (via the PWM pin) gives a wide dimming ratio without color shift.
Temperature grade and package
Junction temperature range is -40°C to 125°C, covering under-hood and exterior lighting environments. The part comes in a 16-MSOP-EP (exposed pad) package — the thermal pad must be soldered to a copper plane for adequate heat transfer; without that via stitch, the junction temperature rises quickly above 400 mA continuous LED current.
Lifecycle and sourcing
The LT3755EMSE-1#WPBF carries an Active lifecycle status with ROHS3 compliance.