What the 100 mA ceiling means for your rail
The LM317LZ-TR is a 100 mA adjustable positive linear regulator in a TO-92-3 (TO-226AA) through-hole package from STMicroelectronics. The 100 mA output current is the practical limit before the junction temperature climbs above the 125 °C maximum in free air — this part is sized for bias rails, reference supplies, or local post-regulation, not for powering a load that draws continuous current above 50–60 mA without a heatsink or airflow.
PSRR and input headroom — cleaning a noisy rail
PSRR is specified at 80 dB to 65 dB at 120 Hz, which is the ripple frequency from a full-wave rectified line — a common input source in industrial and appliance supplies. The 80 dB floor at 120 Hz means this regulator attenuates 120 Hz ripple by a factor of 10,000, so a 1 Vpp ripple on the input becomes roughly 0.1 mVpp at the output. That matters when the load is an analog front-end or a precision reference that cannot tolerate line-frequency hum.
The Tape & Reel variant is the same die and package as the bulk LM317LZ, just in a reel for automated insertion.