36-V, 3-A low-EMI synchronous step-down converter with 1.5-µA IQ

The LMQ664x0 is the industry smallest 36V, 3A (available in 2A and 1A

variants) synchronous step-down DC/DC converter with an integrated bypass and

bootstrap capacitor in an enhanced HotRod QFN package. This easy-to-use converter

supports a wide input voltage range of 2.7V to 36V (after start-up or after

operating) with transients up to 42V.

The LMQ664x0 is

specifically designed to meet low standby power requirements for always-on, industrial

applications. Auto mode enables frequency foldback when operating at light loads,

allowing an unloaded typical current consumption of 1.5µA at 13.5VIN and

high light load efficiency. A seamless transition between PWM and PFM modes along

with very low MOSFET ON resistances makes sure there is exceptional efficiency

across the entire load range. The control architecture (peak current mode) and

feature set are optimized for an ultra-small design size with minimal output

capacitance. The device minimizes input filter size by using dual-random spread

spectrum (DRSS), a low-EMI enhanced HotRod QFN package, and an optimized

pinout. The RT pin can

be used to set the frequency to avoid noise sensitive frequency bands.

There are NC pins between critical high voltage pins, reducing potential

failures (excellent choice pin FMEA). ZEN 2 switcher features enable the device to

support ultra low-EMI applications. The rich feature set of the LMQ664x0 is designed to simplify implementation for

a wide range of industrial end equipment.