The MAX16821 features a unique pin configuration capability that allows the device to be configured for either synchronous buck or synchronous boost mode. Synchronous buck and synchronous boost mode allow LED drivers to operate at very high efficiencies, such as high-power applications such as automotive exterior lighting and emergency lighting systems that are particularly power-hungry.
The wide switching frequency (125kH to 1.5MHz) allows small inductors and filter capacitors to be used in extremely space-constrained devices such as pocket projectors. For systems that require multiple drivers, the MAX16821 also features a 180° phase-delayed clock output that controls another LED driver that is out of phase. This solution reduces LED current ripple, which reduces the size and cost of the input and output filter capacitors.
The MAX16821 operates from 5.4V to 28V and has a built-in 0.03V LED current sense voltage for lowest power consumption (other current sense voltage versions are also available). Other features include programmable hiccup mode, overvoltage protection, reverse current limit, and output enable. The MAX16821 operates over the -40°C to +125°C automotive temperature range and is available in a tiny, lead-free, 5mm × 5mm × 0.8mm, 28-pin TQFN package with an exposed pad. The chip starts at $1.82 (1,000 sheets, FOB USA).