Automotive grade synchronous step-down DC-DC converter with spread spectrum

The Texas Instruments LMR38015-Q1 synchronous buck converter is created to regulate over a wide input voltage range, reducing the necessity for external surge suppression components. The device operates during input voltage dips as low as 4.2V, at nearly 100% duty cycle if needed, making the device an excellent choice for 48V battery automotive applications and MHEV/EV systems as the absolute maximum input voltage is 85V.

The device provides a high voltage enable pin to enable the device by connecting it to the wide input supply voltage or by having precise UVLO control across start-up and shutdown. With built-in filtering and delay, the power-good flag provides a true indication of system status, eradicating the necessity for an external supervisor. The device includes a pseudorandom spread spectrum option for minimal EMI. The switching frequency can be configured between 200kHz and 2.2MHz to avoid noise-sensitive frequency bands. Also, the frequency can be programmed via the RT pin for improved efficiency at low operating frequencies or by having a smaller design size at high operating frequencies.

The device includes built-in protection features such as cycle-by-cycle current limit, hiccup mode short-circuit protection, and thermal shutdown in case of excessive power dissipation. The device is qualified to automotive AEC-Q100 grade 1 and is offered in a 12-pin WSON package.