2 A linear regulator for 5 V rails
The STMicroelectronics L78S05CV is a 5 V fixed-output positive linear regulator rated for 2 A continuous output current — the 'S' in the part number marks the 2 A variant of the standard 78xx family, stepping up from the 1 A L78xx parts without changing the TO-220-3 footprint. Maximum input voltage is 35 V, and the 2 A output makes it suitable for powering 5 V logic rails, sensor supplies, or relay coils in industrial control boards where a switching regulator's noise is undesirable.
Ripple rejection and protection
PSRR is 54 dB at 120 Hz — this is the line-frequency ripple rejection figure; a 54 dB rejection means the output ripple is roughly 0.2 % of the input ripple at 120 Hz, which keeps the 5 V rail clean for analog circuits like op-amp supplies or ADC reference buffers. Built-in protection covers over-current, over-temperature, and short-circuit conditions — the regulator folds back output current during a fault and recovers automatically when the fault clears, eliminating the need for external crowbar or foldback circuits on the board. Quiescent current is 8 mA typical — the ground pin current drawn by the regulator itself; at 2 A load this is negligible, but in always-on standby circuits the 8 mA Iq should be factored into the system power budget.
Package and thermal design
Operating junction temperature range is 0 °C to 150 °C — the 0 °C lower limit means this part is specified for commercial/industrial environments, not extended cold storage or outdoor winter operation below freezing.
Lifecycle and compliance
ROHS3 compliant — meets the current EU RoHS exemption regime (including exemptions for lead in high-melting-temperature solders), so no substance restrictions block its use in new product introductions or export to regulated markets.