The output pulldown current for this device is 0.9mA typical.

Do not rely on the output pulldown circuit for discharging a large amount of output capacitance after the input

supply collapses. When the input supply collapses, reverse current flows from the output to the input, and this

reverse current causes damage to the device. See the Reverse Current section for more details.

6.3.5 Thermal Shutdown

The device contains a thermal shutdown protection circuit to disable the device when the junction temperature

(TJ) of the pass transistor rises to TSD(shutdown) (typical). Thermal shutdown hysteresis makes sure the device

resets (turns on) when the temperature falls to TSD(reset) (typical).

The thermal time-constant of the semiconductor die is fairly short. Thus the device cycles on and off when

thermal shutdown is reached until power dissipation is reduced. Power dissipation during start-up is high from

large VIN – VOUT voltage drops across the device or from high inrush currents charging large output capacitors.

Under some conditions, the thermal shutdown protection disables the device before start-up completes.

For reliable operation, limit the junction temperature to the maximum listed in the Recommended Operating

Conditions table. Operation above this maximum temperature causes the device to exceed operational

specifications. Although the device internal protection circuitry is designed to protect against thermal overall

conditions, this circuitry is not intended to replace proper heat sinking. Continuously running the device into

thermal shutdown or above the maximum recommended junction temperature reduces long-term reliability.

LM1117-Q1

SBVS468A – DECEMBER 2024 – REVISED JUNE 2025

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