Figure 2-4 LMQ66430-Q1 Functional Block Diagram

The LMQ66430-Q1 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 LMQ66430-Q1 is specifically designed to meet low standby power requirements for always-on, automotive applications. Auto mode enables frequency foldback when operating at light loads, allowing an unloaded typical current consumption of 1.5µA at 13.5V_IN 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 MODE/SYNC pin can be used to set or synchronize the frequency to avoid noise sensitive frequency bands. There are NC pins between critical high voltage pins, reducing potential failures (excellent choice pin FMEA). The rich feature set of the LMQ66430-Q1 is designed to simplify implementation for a wide range of automotive end equipment.