-5 V fixed negative rail in a D2PAK tabbed package
The STMicroelectronics L7905ACD2T is a fixed-output negative voltage regulator delivering -5 V at up to 1.5 A. It is a three-terminal device in the D2PAK (TO-263-3) surface-mount package, where the exposed tab is both the thermal pad and the negative output node. The part is intended for negative-rail generation in systems that need a clean, regulated -5 V from an unregulated negative input down to -35 V.
60 dB ripple rejection at 120 Hz — what it means for analog rails
The L7905ACD2T specifies a PSRR of 60 dB at 120 Hz, which is the typical rectified line frequency. That level of ripple rejection means the output sees roughly 1 mV of ripple for every 1 V of input ripple at that frequency — adequate for powering op-amp rails or ADC reference buffers in industrial control boards where the negative supply is derived from a transformer-and-rectifier stage. For switching regulators upstream, the 120 Hz figure is less relevant; you are looking at the PSRR roll-off above a few kHz, which is not specified here.
Obsolete — sourcing through independent distribution
The L7905ACD2T carries an Obsolete lifecycle status.
Protection features and quiescent draw
Built-in over-temperature and short-circuit protection are included, which is standard for this regulator family. The quiescent current is 3 mA — not a low-Iq part, but acceptable for a linear regulator driving a 1.5 A load where the 3 mA overhead is negligible compared to the load current. The typical dropout voltage is 1.4 V at 1 A load, so the input must stay below -6.4 V to maintain regulation at full current.