5V fixed rail, 1.5 A continuous, D2PAK footprint
The L7805ABD2T-TR is a classic 5 V fixed-output linear regulator from STMicroelectronics, delivering up to 1.5 A continuous in the surface-mount D2PAK (TO-263) package. The 68 dB PSRR at 120 Hz means it rejects mains-frequency ripple well — useful when the input comes from a rectified AC source or a switching pre-regulator with residual 100/120 Hz hum.
Dropout and headroom — what the 2 V max means at the board level
Dropout voltage is specified at 2 V maximum at 1 A output current (typical value lower). That sets the minimum input-to-output differential: if your rail is 5 V, the input must stay above 7 V under load to keep regulation. Below that the regulator drops out and the output follows the input minus the dropout. For a 5 V rail fed from a 9 V battery or a 12 V bus, this is comfortable; for a 6.5 V input it is tight. The quiescent current is 6 mA typical — the current the regulator burns just to run its internal bias. At light loads (10 mA out), that 6 mA is a 60 % overhead; at 1.5 A it is negligible. For battery-powered designs where every milliamp matters, a lower-Iq LDO like the LD39020DTPU33R (200 mA output, 80 dB PSRR at 1 kHz) is a more efficient fit.
For a BOM line that calls for a 5 V, 1.5 A fixed regulator in a surface-mount power package, this part is a direct fit with no lifecycle risk.
Built-in over-temperature and short-circuit protection are standard for the 78xx family — the regulator shuts down if the junction exceeds the safe limit or if the output is shorted to ground.