Applications in the automotive and industrial fields are typically used in harsh environments. For applications particularly sensitive to noise, compact, low-noise, and high-efficiency step-down regulators (DC/DC converters) are essential. In these cases, rather than using a DC/DC controller IC with external power MOSFETs, step-down regulator products that offer a smaller footprint are often preferred. This means that single-package or monolithic step-down regulators with integrated power MOSFETs are commonly used. Among them, monolithic regulators operating at a high switching frequency of 2MHz—well above the AM band—enable the use of smaller external components. Furthermore, products with an extremely short minimum on-time (TON) can step down high input voltages directly to the required level without intermediate regulation. This helps reduce both board space and system complexity.

The MAX20402 and MAX20403 step-down DC/DC converters from Analog Devices meet these performance demands. With an input voltage range of 3V to 36V (42V tolerant), they are suitable for use with 12V automotive batteries. The MAX20402 provides a maximum output current of 2.5A, and the MAX20403 supports up to 3.5A. Both feature built-in MOSFETs in a compact 3mm x 3mm QFN package, delivering high efficiency in a small form factor. Supporting 2MHz switching with a minimum on-time of 35ns allows for reduced inductor size and cost. The wideband operation also enables lower input and output capacitance, contributing to overall reductions in system cost and size. In addition, the symmetrical pin layout of the MAX20402 and MAX20403, combined with the 2MHz switching frequency and +/-6% spread spectrum function, helps suppress EMI and minimize radio interference. Simulation models are available, and AC and transient characteristics can be evaluated using EE-SIM, the free online simulator provided on Analog Devices' website.