AP7343D-18FS4-7

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Overview

The AP7343D-18FS4-7 is a fixed-output low dropout regulator manufactured by Diodes Incorporated, delivering a precise 1.8V output with a guaranteed maximum current of 300mA. It operates within an input voltage range of 1.7V to 5.25V and features high power supply rejection ratio (PSRR) of 75dB at 1kHz alongside low output noise of 60µVrms from 10Hz to 100kHz. The device incorporates an enable pin for power management, built-in short-circuit protection, and thermal shutdown. It utilizes the X2-DFN1010-4 package and includes an auto-discharge feature upon shutdown.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Feature Summary

• Integrated enable control allowing active shutdown via the EN pin
• High ripple rejection capability suitable for sensitive RF applications
• Built-in discharge mechanism to rapidly reduce output voltage when disabled
• Compact footprint design optimized for dense PCB layouts

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Applications

• RF power supplies
• Portable media players
• Wireless communication adapters
• Smartphones and tablets

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Procurement Notes

Verify the specific suffix 'D' indicates the presence of the output discharge function, as non-discharge variants exist within the same family. Confirm the 'FS4' designation corresponds to the X2-DFN1010-4 package type required for your layout. Ensure the ordering code matches the exact 1.8V fixed output requirement. Cross-reference the datasheet revision to confirm compatibility with your manufacturing process.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Selection Notes

Select this component when low quiescent current and high PSRR are critical for system efficiency and signal integrity. The integrated discharge feature distinguishes it from standard versions, making it suitable for battery-powered devices requiring rapid power-down states. Verify that the input voltage remains above the minimum threshold while accounting for dropout voltage under full load conditions.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Part Context

This part belongs to the AP7343 series of low dropout regulators designed for handheld communication equipment. The series offers various fixed output voltages ranging from 0.9V to 3.6V. The 'D' suffix specifically denotes the inclusion of an internal N-channel auto-discharge resistor connected to the output, which actively pulls the voltage down when the enable pin is deactivated.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Replacement Considerations

AP7343-18FS4-7 serves as the non-discharge equivalent within the same package.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators FAQ

What is the function of the 'D' suffix in the part number?

The 'D' suffix indicates that the regulator includes an internal auto-discharge circuit that actively pulls the output voltage to ground when the enable pin is set to a low state.

How does the enable pin operate?

Driving the EN pin high turns the regulator on, while pulling it low activates the shutdown mode and engages the discharge function if present.