LM1117IMPX-3.3

Overview

The LM1117IMPX-3.3 is a fixed-output low-dropout linear regulator manufactured by Texas Instruments, providing a stable 3.3 V output with a maximum load current of 800 mA. It operates within an input voltage range up to 15 V and features a typical dropout voltage of 1.2 V at full load. The device ensures high precision with line regulation of 0.2% and load regulation of 0.4%. It includes built-in thermal shutdown and current limiting for protection. The component is housed in a space-saving SOT-223 package and supports an operating junction temperature range from -40°C to +125°C.

Feature Summary

• Provides a fixed 3.3 V output with ±1% accuracy using a Zener trimmed bandgap reference.
• Features integrated current limiting and thermal shutdown to protect against overload conditions.
• Delivers low dropout performance, requiring only 1.2 V differential at 800 mA load.
• Requires a minimum 10 µF tantalum output capacitor to ensure stability and transient response.

Applications

• AC drive power stage modules
• Merchant network and server PSU
• Industrial AC/DC power supplies
• Ultrasound scanners
• Servo drive control modules

Procurement Notes

Verify the specific suffix 'IMPX' confirms the SOT-223 surface-mount package and industrial temperature grade (-40°C to +125°C). Confirm the '-3.3' designation matches the required fixed 3.3 V output. Ensure the 'NOPB' suffix indicates lead-free and halogen-free compliance as per RoHS standards. Cross-reference the manufacturer part number with official TI documentation to validate authenticity and revision status before procurement.

Selection Notes

Select this component when a fixed 3.3 V rail is needed with up to 800 mA capability in a compact SMT footprint. It is suitable for replacing older 78xx series regulators where lower dropout voltage is critical. Ensure the application provides sufficient headroom above the 1.2 V dropout voltage. Verify that the PCB layout allows for adequate thermal dissipation given the SOT-223 package's thermal resistance characteristics under expected load conditions.

Part Context

This device belongs to the LM1117 family of 800 mA low-dropout linear regulators. It serves as a legacy alternative to newer Texas Instruments parts like the TLV1117 or TLV761, which offer improved functionality or drop-in compatibility. The LM1117 is widely used in general-purpose power management applications requiring reliable linear regulation with moderate current capacity.

Replacement Considerations

Texas Instruments recommends the TLV1117 as a newer drop-in alternative. For fixed output configurations in SOT-223 packages with improved functionality, the TLV761 is suggested as a replacement option.