3A buck regulator with a 60V input ceiling
The Texas Instruments LM2576HVSX-ADJ/NOPB is a SIMPLE SWITCHER® step-down buck regulator delivering up to 3A from a 4V to 60V input rail. The adjustable output version sets anywhere from 1.23V up to 57V using two external resistors. This is the high-voltage variant of the LM2576 family, meaning the 60V input max covers 48V industrial supplies and 24V automotive systems with load-dump headroom. The switching frequency is fixed at 52kHz — low enough to keep EMI predictable and avoid AM-band interference, but it forces larger external magnetics and output capacitors than a 150kHz or 500kHz switcher would. The trade-off is simpler layout and no need for frequency-sync or spread-spectrum design effort.
Junction temperature range and package thermal path
The DDPAK/TO-263-5 package exposes a large copper tab on the bottom — that tab is the main heat path. This differs from the 6-lead TO-263 footprint used by some other LM2576 package options, so confirm the PCB land pattern matches the 5-lead DDPAK before committing the layout.
External diode is mandatory — no synchronous rectification
The LM2576HVSX-ADJ/NOPB does not include a synchronous rectifier — it requires an external Schottky catch diode (typically a 3A–4A, 60V-rated part like the 1N5822 or MBR360) between the switch node and ground. The diode conducts during the off-time and its forward voltage directly adds to the conversion loss. A fast-recovery or Schottky diode with low Vf keeps efficiency acceptable at 52kHz.
The SIMPLE SWITCHER family has been in production for decades, and the high-voltage adjustable version remains a current catalog item for designs that need the 60V input capability.