Boost regulator with integrated 1.2A switch — sizing the power stage
The MIC2291YD5: This is a step-up (boost) DC-DC regulator with the power switch built in — the internal switch is rated for 1.2A peak current. At 1.2MHz switching frequency, the external inductor and capacitor values stay small, which keeps the total solution footprint tight for portable battery-powered gear like camera flash modules or LED backlight drivers. The 2.5V to 10V input range means it starts from a single Li-ion cell at 3.0V and can run up to a 2S battery pack. Output voltage is set by the external resistor divider; the boost topology can deliver up to the switch voltage rating minus the diode drop.
PWM dimming and temperature grade — application fit
The PWM dimming input allows direct LED current control from a microcontroller PWM output — the regulator's internal error amplifier responds to the duty cycle, so the LED brightness tracks the PWM signal linearly. This is the standard interface for camera flash strobe intensity or display backlight dimming. A camera module in an outdoor security camera or an engine-bay ADAS camera sees ambient well above 85°C; the 125°C junction rating gives margin before thermal shutdown.
TSOT-23-5 package — board-fit note
Housed in a TSOT-23-5 package — the thin SOT-23 variant with a 0.9mm max seated height. The five-pin footprint is standard for small boost converters; the thermal pad on the underside (if present on the specific variant) should be soldered to a PCB copper plane to keep junction temperature within limits at full 1.2A switch current.