12 V fixed rail, 1.5 A continuous — TO-263 D²Pak
The LM7812S/NOPB is a fixed 12 V output linear regulator from the classic 78xx family, delivering up to 1.5 A continuous. The 72 dB PSRR at 120 Hz means it attenuates the 100/120 Hz ripple from a rectified mains supply by a factor of ~4000 — relevant for powering analog front-ends or sensor bias rails where clean DC matters. The 2 V max dropout at 1 A sets the minimum input headroom: the unregulated DC input must stay above 14 V at full load to keep the output in regulation. The 8 mA quiescent current is typical for a bipolar linear regulator of this output rating.
Package and thermal budget
Housed in a TO-263-3 (D²Pak) surface-mount package with an exposed tab on the bottom. A 2 oz copper plane of at least 1 in² is typical to keep the junction below 125°C at 1.5 A load. For ambient temperatures above 70°C, derate the output current or increase the copper area to stay within the junction limit.
Protection features and supply posture
On-chip protection includes over-temperature shutdown and short-circuit current limiting — the regulator survives a sustained output short without damage, though the die temperature will cycle near the thermal limit.