The MC34063ABN is a classic switching regulator controller with an integrated 1.5 A switch transistor, capable of step-up (boost) or step-down (buck) conversion from a single supply rail between 3 V and 40 V. The 1.5 A switch current rating is the peak current the internal transistor can handle — the actual output current will be lower, depending on the input-to-output voltage differential and the inductor value. For a 12 V to 5 V buck, expect around 750 mA continuous before the switch saturates. The 33 kHz switching frequency is low by modern standards, which means the inductor and output capacitor will be physically larger than what you'd use with a 500 kHz part. That's a trade-off: the low frequency keeps switching losses down and makes layout less critical, but the magnetics take up board space.
Through-hole 8-DIP package — the repair-bench favourite
The 8-DIP (0.300-inch, 7.62 mm) through-hole package is the go-to for rework and low-volume builds. No hot air required — a standard soldering iron and a desoldering pump are all you need to swap it. The scorch mark tells you which part died; the 8-DIP lets you replace it without lifting pads. Compared to the surface-mount MC34063AD (SO-8), the DIP version has a larger thermal footprint — the copper pad area under the body is smaller, so the junction-to-ambient thermal resistance is higher. For continuous loads above 500 mA, a small heatsink or airflow helps keep the junction below the 85°C ambient ceiling.
The through-hole package is widely available through independent distribution; confirm the date-code freshness at quote time.