Package and mounting
The Maxim Integrated MAX1553ETA+T is a DC-DC boost regulator specifically designed for LED backlight applications. It integrates the switching FET internally, so the external BOM stays tight — just the inductor, input/output caps, and a current-set resistor. The single output can drive a string of series-connected LEDs up to 40V, which covers most small-to-medium LCD panel backlights or indicator arrays. Dimming is handled either by a PWM signal on the control pin or by varying the analog reference, giving the firmware team flexibility on brightness granularity.
Supply range and switch current — the real limits
Input voltage range is 2.7V to 5.5V, so it runs happily from a single lithium-ion cell, a 3.3V rail, or a 5V USB supply. The internal switch is rated for 480mA peak — that's the current limit through the inductor, not the LED current directly. For a typical white LED forward voltage around 3.2V, a 40V output can stack about 12 LEDs in series, but the total LED current is set by the sense resistor and must stay within the switch's capability after accounting for the boost ratio. If the target LED current times the duty cycle pushes past 480mA, the part will current-limit and the output drops.
Package and temperature grade
Housed in an 8-TDFN (3x3mm) with an exposed pad — that pad needs a solid thermal via stitch to the ground plane if you're running near the 480mA switch limit or in a warm enclosure. The operating temperature range is -40°C to 85°C, which covers industrial and outdoor-rated equipment but not under-hood automotive. Surface-mount only, as you'd expect for a small-format boost converter.
Lifecycle and compliance
It's ROHS3 compliant, which clears the restriction-of-hazardous-substances check for new designs shipping into Europe or California.