Adjustable 1.23 V to 37 V buck — the 3 A workhorse now obsolete
The Texas Instruments LM2576T-ADJ is a SIMPLE SWITCHER® step-down buck regulator delivering 3 A continuous output from a 4 V to 40 V input rail. The output is adjustable from 1.23 V up to 37 V, set by a pair of external resistors — no secondary LDO needed for non-standard voltages.
52 kHz switching — inductor size vs ripple trade-off
The 52 kHz switching frequency is low by modern standards — expect a physically larger inductor (typically 100 µH to 330 µH for 3 A) compared to a 150 kHz+ part. The trade-off is lower switching losses and a simpler layout with less radiated noise concern. Output ripple is higher; a low-ESR output capacitor helps keep it within budget.
TO-220-5 through-hole — heatsink mandatory at full load
The TO-220-5 package with a metal tab requires a heatsink for sustained 3 A operation. No synchronous rectifier — the external Schottky diode handles the freewheeling current and must be rated for the full output current.
For new designs, consider a pin-compatible third-party clone; for existing BOM lines, source through independent distribution against an RFQ.