The APM80905 is a 36 V, 4 A, ASIL-B, low EMI, synchronous buck switching regulator module that provides a regulated current output to drive high-power infrared or standard LEDs. The module integrates both the high-side and low-side N-channel MOSFET switches and high frequency input voltage and boot capacitors. The APM80905 also includes several fault protection features including a PWM dimming signal monitor with configurable LED on-time and duty cycle limits to simplify the design of Driver Monitoring Systems.
The switching frequency is programmable from 400 kHz to 2.2 MHz with an external resistor. Output current is programmable by an external current sense resistor, and the output voltage is automatically adjusted to drive one or multiple LEDs in series, optimizing system efficiency regardless of the number of LEDs in the string. The analog dimming input, ADIM, allows for LED current calibration or thermal foldback with an external NTC thermistor. An open-drain fault flag pin FFn is pulled low to alert the system or controller a fault was detected.
The APM80905 is offered in a compact, thermally enhanced 4x4x2.1 mm QFN package with wettable flanks.
