Negative -12V rail, 1.5A, TO-220
The L7912CV-DG is a fixed -12V output negative linear regulator from STMicroelectronics, rated for 1.5A continuous output in a TO-220-3 through-hole package. It is the go-to part when you need a clean, low-noise negative supply for op-amp rails, bipolar ADC references, or analog front ends that run off split supplies.
PSRR 60 dB at 120 Hz — ripple rejection for audio and instrumentation
With a PSRR of 60 dB at 120 Hz, the L7912CV-DG attenuates full-wave-rectified ripple by a factor of 1000. For a -35V input rail carrying 1 Vpp of 120 Hz ripple, the output sees roughly 1 mVpp — clean enough for most 16-bit analog chains without a post-filter. The dropout voltage is 1.1 V typical at 1 A load. That means the input must stay below -13.1 V to maintain regulation at 1 A; at lighter loads the dropout is lower, but the -35V absolute maximum input gives headroom for unregulated transformer-rectifier rails.
Protection and quiescent current
Built-in over-temperature and short-circuit protection let the L7912CV-DG survive output shorts and thermal overload without external clamp diodes or foldback circuits. Quiescent current is 3 mA typical — negligible in a 1.5 A rail but worth noting for always-on low-power systems.