What this regulator does on the board
The MC34063EBD-TR is a single-output, adjustable switching regulator that can be configured as a step-up (boost) or step-down (buck) converter, with positive or negative output polarity. Its internal 1.5 A switch handles moderate loads — think 500 mA to 1 A continuous after derating — without an external pass transistor for many designs. The 33 kHz switching frequency keeps the inductor physically larger than a modern 500 kHz part, but the trade-off is lower radiated noise and a simpler layout that tolerates more parasitic capacitance.
Input and output voltage envelope
Input can range from 3 V to 40 V, so it works off a single Li-ion cell (3.7 V nominal) up through a 24 V industrial rail or 36 V battery pack.
Housed in an 8-SOIC (0.154" wide, 3.90 mm body) surface-mount package, it reflows on a standard lead-free profile and fits a two-layer PCB without micro-vias.