Fixed -12 V rail in a TO-220 through-hole package
The L7912ACV-DG is a single-output negative linear regulator delivering a fixed -12 V at up to 1.5 A from a -35 V maximum input. The TO-220 through-hole package suits point-of-load regulation on a main board or a separate heatsink — the tab is ground and the thermal path goes through the mounting hole to the chassis or PCB copper. Its 60 dB PSRR at 120 Hz provides meaningful ripple rejection from a full-wave rectified line-frequency supply — relevant when the regulator feeds an analog front end or a sensitive negative rail in an audio or instrumentation circuit.
Dropout and quiescent current for load budgeting
The typical dropout voltage is 1.1 V at 1 A — the input must stay at least 1.1 V more negative than -12 V under load to maintain regulation. Quiescent current runs 3 mA, which adds to the thermal budget but is low enough to ignore in most supply-rail designs. Built-in over-temperature and short-circuit protection means the regulator survives a momentary output short without external clamp diodes — useful during board bring-up or a downstream fault.
STMicroelectronics lists the L7912ACV-DG as Obsolete. For BOM lines that must stay with a TO-220 negative regulator, the closest active sibling is the L7912AV — same base number, same package, same fixed -12 V output — but confirm the exact spec tolerance and operating temperature range against the original design requirements. Sourcing now runs through independent distribution and spot-market channels.