Buck-boost in an 8-pin DIP – legacy workhorse
The MC33063AP is a 1.5A (switch) adjustable buck-boost regulator from Texas Instruments, packaged in an 8-DIP (0.300-inch, 7.62mm) through-hole package. It accepts an input from 3V to 40V and can produce a positive or negative adjustable output down to 1.25V (minimum) or up to 40V (switch limit). The 100kHz switching frequency is fixed — no external sync or frequency foldback — which simplifies the inductor selection but limits the minimum practical output ripple filter size compared to modern 400kHz+ parts.
Confirm the board footprint and the mating socket or solder-hole pattern before committing.
The 1.5A switch current rating is the peak current the internal transistor can handle; the actual output current depends on the topology (buck vs boost), input-output differential, and inductor ripple. For a typical 12V-to-5V buck conversion, expect around 0.5–0.8A continuous output before the switch current limit is reached. No synchronous rectifier is integrated, so the freewheeling diode must be added externally — a Schottky with adequate reverse voltage and forward current rating. This adds a diode drop to the conduction loss, which matters at low output voltages. The adjustable output is set by two external resistors; the internal reference is 1.25V. The output can be configured for positive or negative regulation, which is useful for generating a -5V rail from a positive input in legacy mixed-signal boards.
Package and mounting – through-hole reality
The 8-DIP package (0.300-inch body width, 7.62mm) is a standard through-hole footprint. No exposed pad or thermal slug — heat is dissipated through the leads and the copper traces on the PCB. The Tube shipping format is typical for through-hole DIPs; no tape-and-reel option is listed. For automated insertion, a tube-fed handler is required.