The LM317KCS carries a Last Buy status from Texas Instruments, meaning the manufacturer has scheduled end-of-production and is accepting final orders within a defined window.
1.5 A output and adjustable range
This is a positive adjustable linear regulator delivering up to 1.5 A continuous output. The output voltage adjusts from 1.25 V minimum up to 37 V maximum, set by two external resistors — the classic LM317 topology that needs no fixed tap. The 1.5 A rating is the headline load budget: at full current the TO-220-3 package requires a heatsink sized for the dropout voltage times load, because the junction temperature is rated 0 °C to 125 °C.
PSRR and ripple rejection
Power-supply rejection ratio is specified at 80 dB to 65 dB at 120 Hz. That 80 dB floor at the fundamental ripple frequency of a full-wave rectifier means the output sees roughly 1/10,000th of the input ripple — a practical number for clean analog rails. The 65 dB at the same frequency is the worst-case corner; if your load draws near the 1.5 A limit, expect the lower end of that range.
Protection features and quiescent current
On-chip protection includes over-current, over-temperature, and short-circuit — the regulator survives a sustained output short without damage, though the thermal shutdown cycles until the fault clears. Quiescent current is 10 mA typical; that is the current the regulator burns to run its internal reference and error amp, and it flows to ground regardless of load. In battery-powered designs the 10 mA Iq is a standing drain that must be factored into the standby budget.