The LMR36503-Q1 is a wide input, low-quiescent current, high-performance regulator that can operate over a wide range of duty ratio and the switching frequencies, including sub-AM band at 400 kHz and above AM band at 2.2 MHz. During wide input transients, if the minimum ON-time or the minimum OFF-time cannot support the desired duty ratio at the higher switching frequency settings, the switching frequency is reduced automatically, allowing the LMR36503-Q1 to maintain the output voltage regulation. With an internally-compensated design optimized for minimal output capacitors, the system design process with the LMR36503-Q1 is simplified significantly compared to other buck regulators available in the market.

The LMR36503-Q1 is designed to minimize external component cost and solution size while operating in all demanding automotive environments. The LMR36503-Q1 family includes variants that can be set-up to operate over a wide switching frequency range, from 200 kHz to 2.2 MHz, with the correct resistor selection from RT pin to ground. To further reduce system cost, the PGOOD output feature with built-in delayed release allows the elimination of the reset supervisor in many applications.

The LMR36503-Q1 family is designed to reduce EMI/EMC emissions. The design includes a pseudo-random spread spectrum switching frequency dithering scheme, has no bond-wire flip-chip on the lead (HotRod™) package, and is available with the MODE/SYNC feature (select variants), allowing synchronization to an external clock, when available. Together, these features eliminate the need for any common-mode choke or shielding or any elaborate input filter design scheme, greatly reducing the complexity and cost of the EMI/EMC mitigation measures.

The LMR36503-Q1 comes in an ultra-small 2-mm x 2-mm QFN package with wettable flanks allowing for quick optical inspection along with specially designed corner anchor pins for reliable board level solder connections.