76V input buck in an 8-pin SOIC
The MAX5033BASA+ is a step-down (buck) switching regulator from Analog Devices, delivering a fixed 5V output at up to 500mA from a 7.5V to 76V input rail. The 76V maximum input covers 48V telecom buses, 24V industrial supplies, and 12V automotive systems with headroom for transients — no external pre-regulator needed for those rails.
125 kHz switching and the thermal budget
Switching at 125 kHz, the MAX5033BASA+ keeps switching losses low enough that the 8-SOIC package can dissipate the heat from 500mA output without a heatsink in most layouts — the junction temperature range is -40°C to +125°C. The downside of the low frequency is a larger inductor than a 500 kHz part would need; plan for a 47 µH to 100 µH shielded inductor in the BOM. No synchronous rectifier is used internally, so the external Schottky diode carries the inductor current during the off-time. The diode's forward drop and the 500mA output current set the rectifier's power dissipation — a 1A-rated Schottky with a Vf around 0.5V keeps the diode junction below 100°C in still air.