52 kHz switching — inductor sizing trade-off
The LM2577S-ADJ switches at 52 kHz, a deliberate choice from the SIMPLE SWITCHER® era. That low frequency means larger inductors and more output ripple than a modern part, but it also gives you wider loop stability margins and less switching loss in the internal 3A switch.
Boost, flyback, forward — one part for three topologies
This regulator handles boost, flyback, and forward converter topologies from a single adjustable output. The output can be configured positive or negative, and the 1.23V reference lets you set the output up to 60V (switch rating). That flexibility is rare in a single IC — most modern switchers are topology-locked. For a bench supply or a multi-rail retrofit, it saves board space and BOM line count.
NRND — plan your BOM around a last-time buy
For repair or legacy support, stock up now — the window is open but finite.
TO-263-5 DDPAK — hand-solderable with care
The TO-263-5 (DDPAK) package has a large exposed pad on the bottom for thermal dissipation. You can hand-solder it with a hot-air station or a reflow skillet — the tab needs a good solder joint to the board copper for thermal performance.