Sizing a 12 V rail from a 48 V bus
The LM2576HVSX-12 is a fixed 12 V output buck from the SIMPLE SWITCHER® family, rated for 3 A continuous output at 52 kHz switching frequency. Its 60 V input maximum lets it regulate down from a 48 V telecom rail or a 24 V industrial supply without an intermediate stage.
The 52 kHz switching frequency keeps the inductor physically small — a 100 µH to 330 µH shielded type is typical — but the output ripple is higher than a modern 400 kHz+ switcher, so the output capacitor bank needs a lower ESR than a generic aluminium electrolytic. The 3 A output is continuous at 25°C ambient; at 125°C junction the current derating curve in the datasheet applies, so a 3 A load at high ambient may need forced air or a larger copper area on the DDPAK tab.
NRND — planning the last-time buy
The part is RoHS non-compliant, which may restrict its use in new EU-market products without an exemption.
The 5-lead DDPAK footprint is shared with the through-hole TO-220 version (LM2576T-12), so a board designed for the TO-220 can be adapted with a different layout for the surface-mount variant.