LM1117T-3.3

Overview

The LM1117T-3.3 is a fixed-output low-dropout linear regulator manufactured by Texas Instruments, providing a nominal 3.3 V output with a maximum load current of 800 mA. It operates within an input voltage range up to 15 V and maintains regulation with a dropout voltage of approximately 1.2 V at full load. The device features line regulation of 0.2% maximum and load regulation of 0.4% maximum. It includes built-in thermal shutdown and current limiting protection. The component is housed in a TO-220 package and supports an operating junction temperature range from 0°C to 125°C.

Feature Summary

• Integrated thermal shutdown and current limiting for robust operation under fault conditions
• Low dropout voltage performance enabling efficient regulation with minimal input-to-output differential
• High ripple rejection ratio suitable for noise-sensitive applications
• Requires minimum output capacitance for stability and transient response improvement

Applications

• Post-regulator for switching DC-DC converters
• Battery charger circuits
• Portable instrumentation power supplies

Procurement Notes

Verify the specific suffix 'T' indicates the TO-220 through-hole package variant when sourcing. Confirm the absence of the 'I' prefix ensures compliance with the commercial 0°C to 125°C temperature range rather than the industrial -40°C to 125°C range. Ensure the ordering part number matches the exact pin configuration and thermal characteristics required for the target PCB layout.

Selection Notes

Select this component when a stable 3.3 V rail is needed with up to 800 mA capacity. Ensure the input voltage remains above the output voltage plus the dropout voltage across all operating temperatures. Verify that the application can accommodate the required output capacitor type, typically tantalum or low-ESR electrolytic, to maintain loop stability and prevent oscillation.

Part Context

This device belongs to the LM1117 family of low-dropout regulators, which also includes adjustable versions and other fixed voltages like 1.8 V, 2.5 V, and 5 V. The family shares common internal architectures featuring Zener-trimmed bandgap references. The TO-220 package variant provides higher thermal dissipation capabilities compared to surface-mount options like SOT-223 or WSON.

Replacement Considerations

LM1117T-3.3/NOPB