LD6815TD/18P,125

Overview

The LD6815TD/18P,125 is a low dropout regulator (LDO) from NXP USA Inc., featuring a fixed 1.8 V nominal output voltage and a maximum load current of 150 mA. It operates within an input voltage range of 2.3 V to 5.5 V and delivers a typical dropout voltage of 250 mV at full load. The device provides high power supply rejection ratio (PSRR) of 75 dB at 1 kHz and exhibits low RMS output noise of 40 µV between 10 Hz and 100 Hz. It incorporates an auto discharge function via a pull-down transistor in disabled mode, ensuring a low-ohmic output state. The component is housed in a compact SOT753 (TSOP5) plastic package.

Feature Summary

• Integrates an auto discharge function using a pull-down switching transistor to provide a low-ohmic output state when disabled.
• Delivers ultra-high power supply rejection ratio for effective suppression of input voltage ripples and noise.
• Includes overcurrent protection and high-level electrostatic discharge protection capabilities.
• Maintains extremely low quiescent current consumption during shutdown mode.

Applications

• Smartphones
• Tablet PCs
• Mobile handsets
• Portable media players

Procurement Notes

Verify the specific suffix 'P' confirms the presence of the pull-down auto-discharge feature, as distinct from the 'H' variant which offers a high-ohmic state. Confirm the ordering code matches the required 1.8 V output specification. Ensure compatibility with the SOT753 surface-mount package dimensions for PCB layout. Validate that the application environment stays within the specified ambient temperature range of -40 °C to +85 °C for optimal performance.

Selection Notes

Select this component when a fixed 1.8 V rail is required with minimal footprint constraints. The pull-down feature is critical if rapid output capacitor discharge is necessary upon system shutdown. Consider the 150 mA current limit against peak load demands. The high PSRR makes it suitable for noise-sensitive analog sections in mobile devices. Verify input voltage stability remains above the minimum operating threshold under all load conditions.

Part Context

This part belongs to the LD6815 series of low dropout regulators designed for portable electronics. The series shares common electrical characteristics but varies by output voltage and disabled-state behavior. The 'TD' designation indicates the tape-and-reel packaging format, while '18' specifies the 1.8 V output. The 'P' suffix differentiates it from the high-ohmic version, defining its internal pull-down architecture for output discharge management.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Engineers must verify pinout compatibility and electrical specifications when considering alternative LDOs from other manufacturers. Ensure any replacement supports the required 150 mA load and 1.8 V output with similar PSRR characteristics.