12 V fixed rail, 1.5 A continuous — the headroom and dropout decision
The UA7812CKCE3 is a fixed 12 V positive-output linear regulator delivering up to 1.5 A. Ripple rejection is 61 dB at 120 Hz, which attenuates full-wave rectifier ripple by a factor of roughly 1100 — a 1 Vpp ripple on the input appears as under 1 mVpp on the output, making this part suitable for powering analog front-ends or reference circuits from a line-frequency supply.
Protection suite and thermal envelope
Built-in protection covers over-current, over-temperature, reverse polarity, and short-circuit conditions — the regulator survives a sustained output short without damage, and the thermal shutdown prevents junction runaway above 125°C. Operating junction temperature range is 0°C to 125°C, which covers commercial and most industrial ambient environments. The TO-220-3 package allows direct mounting to a heatsink via the metal tab — the tab is electrically common with the output pin, so an insulating pad and washer are needed if the heatsink is grounded.