LD1117D18

Overview

The LD1117D18 is a fixed positive low-dropout linear regulator manufactured by STMicroelectronics, delivering a precise 1.8 V output voltage with a maximum load current of 800 mA. It operates within an input voltage range of 3.3 V to 15 V and maintains a typical dropout voltage of 1 V at full load. The device features tight output voltage tolerance of ±1% at 25°C and includes internal thermal overload and short-circuit current limiting protections. Designed for high efficiency via an NPN pass transistor, it requires only a minimum 10 μF output capacitor for stability and is housed in an SO-8 surface-mount package.

Feature Summary

• Fixed 1.8 V output with ±1% accuracy at 25°C
• Low dropout voltage of approximately 1 V at 800 mA
• Integrated thermal shutdown and current limit protection
• High efficiency due to NPN pass transistor architecture

Applications

• Battery-powered systems requiring efficient voltage regulation
• Post-regulators for switching power supplies
• Portable equipment and handheld devices
• Communication products and instrumentation

Procurement Notes

Verify the specific suffix 'D' indicates the SO-8 package variant when sourcing. Confirm RoHS compliance status as manufacturing processes evolve. Ensure the application circuit includes the recommended minimum 10 μF output capacitor to guarantee stability under all load conditions. Check for end-of-life notices on legacy LD1117 variants before finalizing procurement plans.

Selection Notes

Select this component when a stable 1.8 V rail is required with moderate current demands up to 800 mA. It is suitable for applications where input voltage exceeds output by at least 1 V. Consider thermal dissipation capabilities based on the SO-8 package limitations. Compare against adjustable versions if variable output flexibility is needed instead of a fixed voltage.

Part Context

Part of the LD1117 family of low-dropout regulators from STMicroelectronics. The series offers various fixed voltages and adjustable options in multiple packages including TO-220, DPAK, SOT-223, and SO-8. This specific model targets space-constrained designs needing reliable linear regulation with minimal external components.

Replacement Considerations

LD1117DT18TR (TO-252 package) offers similar electrical performance in a different surface-mount form factor. LD1117S18CTR (SOT-223 package) provides comparable specifications in a compact leaded package. Verify pin compatibility and thermal characteristics when substituting these alternatives.