The LMR36503E-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 400kHz and above AM band at 2.2MHz. 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 LMR36503E-Q1 to maintain the output voltage regulation. With an internally-compensated design optimized for minimal output capacitors, the system design process with the LMR36503E-Q1 is simplified significantly compared to other buck regulators available in the market.

The LMR36503E-Q1 is designed to minimize external component cost and design size while operating in all demanding automotive environments. The LMR36503E-Q1 family includes variants that can be set-up to operate over a wide switching frequency range, from 200kHz to 2.2MHz, 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 LMR36503E-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 LMR36503E-Q1 comes in an ultra-small, 2mm × 2mm QFN package with wettable flanks, allowing for quick optical inspection along with specially designed corner anchor pins for reliable board level solder connections.