100 mA output — the low-current LM317 for tight spaces
The LM317LZ/LFT1 is the 100 mA member of the LM317 adjustable regulator family, in a TO-92-3 through-hole package. It shares the classic adjustable output architecture — set with two external resistors — but at a fraction of the current of the 1.5 A LM317T. This makes it the natural choice when the load is under 100 mA and board space or cost is the constraint.
Ripple rejection at 120 Hz — what 80 dB ~ 65 dB means
PSRR of 80 dB ~ 65 dB at 120 Hz tells you how much mains-frequency ripple the regulator knocks down. At 80 dB, a 1 Vpp ripple on the input becomes about 100 µVpp on the output — clean enough for most analog and sensor supply rails. The PSRR drops as the output voltage rises or the load current increases; the 65 dB floor is the worst-case corner. If your design feeds a precision ADC or a microphone bias, budget for this roll-off.
Protection features — over-current, over-temperature, short-circuit
Built-in over-current, over-temperature, and short-circuit protection mean the regulator survives a momentary output short or a thermal overload without external clamp diodes. The thermal shutdown threshold is typically around 150°C junction; the part cycles on and off until the fault clears. For a 100 mA part in a TO-92, this is the safety net that keeps the BOM simple.