What the 1.5 A switch and 33 kHz mean for your rail
The MC34063ABD-TR integrates a 1.5 A switch transistor — that's the peak current the internal transistor can handle, not the continuous output current. The 33 kHz switching frequency keeps the switching losses low enough that the part doesn't need a heatsink at moderate loads, but it forces you into a larger inductor than a modern higher-frequency part would. Synchronous rectification is not supported, which means the diode forward drop eats into efficiency at low output voltages; a Schottky diode external is standard practice.
Input range and temperature grade — where it fits
The input voltage range spans 3 V to 40 V, covering a wide variety of logic rails and industrial supplies. Keep the copper area under the IC generous on the PCB to help dissipate the heat from the internal switch.