The LM3642TL-LT is a 4MHz fixed-frequency synchronous boost converter plus 1.5A constant current driver for a high-current white LED. The high-side current source allows for grounded cathode LED operation providing Flash current up to 1.5A. An adaptive regulation method ensures the current source remains in regulation and maximizes efficiency. The LM3642 is controlled via an I2C-compatible interface. Features include: a hardware flash enable (STROBE) allowing a logic input to trigger the flash pulse and a TX input which forces the flash pulse into a low-current Torch Mode allowing for synchronization to RF power amplifier events or other high-current conditions. The 4MHz switching frequency, over-voltage protection and adjustable current limit settings allows the use of tiny, low-profile inductors and (10 μF) ceramic capacitors.
- Synchronization Input for RF Power Amplifier Pulse Events
- 1.5A High-Side Current Source for Single LED
- Accurate and Programmable LED Current from VIN Flash Monitor Optimization
- 400 kHz I2C-Compatible Interface > 85% Efficiency in Torch Mode (@ 100 mA) and Flash Mode (@1A to 1.5A)
- Accurate Programmable Torch LED Currents from 48.4 mA to 375 mA
- Soft-Start Operation for Battery Protection Hardware Strobe Enable