What the 1.5A output and 2V dropout mean for your rail
The L7808ABV-DG is a positive fixed 8V linear regulator from STMicroelectronics' 78xx family, delivering up to 1.5A continuous output in a TO-220-3 through-hole package. At 1.5A and a 12V input, the regulator dissipates 6W. The TO-220 tab, bolted to a heatsink with thermal compound, keeps the junction below the 125°C max when the ambient is 85°C and the sink-to-ambient thermal resistance is under 10°C/W. Without a heatsink, derate to about 0.5A at 85°C ambient.
PSRR 62dB at 120Hz — filtering the rectified line ripple
The 62dB PSRR at 120Hz means the regulator attenuates full-wave-rectified ripple by a factor of 1250. A 1Vpp ripple on the input at 120Hz becomes 0.8mVpp on the 8V output. This matters for analog loads — an op-amp powered from this rail sees the residual ripple as a 120Hz tone in the signal path unless post-filtered. PSRR rolls off above 10kHz; above 100kHz the regulator's loop gain drops and bypass capacitors at the input and output (10µF electrolytic + 100nF ceramic) become the main ripple attenuation. The 6mA quiescent current is the price of that loop gain — it's fixed regardless of load, so at light loads the efficiency drops.
Protection features and temperature range for industrial use
Built-in over-temperature shutdown and short-circuit current limiting protect the regulator and downstream circuitry. The thermal shutdown triggers at approximately 150°C junction, with a 10°C hysteresis — a sustained overload cycles the output on and off until the fault clears. The short-circuit protection folds back the output current to roughly 0.5A, limiting dissipation during a hard short. The -40°C to 125°C operating temperature range covers industrial enclosures, outdoor telecom cabinets, and engine-bay electronics. At -40°C startup, the output voltage may dip 2% below nominal until the die warms — the 8V fixed output stays within 5% tolerance across the full temperature band.