Diodes Incorporated AP7315D-18W5-7

Overview

AP7315D-18W5-7 from Diodes Incorporated is a 150mA, 1.8V fixed-output low-dropout linear regulator with enable control, ±1% output voltage accuracy, 75dB PSRR at 1kHz, and 60µV_rms output noise (10Hz–100kHz). It operates from 1.7V to 5.25V input and delivers stable power to RF supply rails in portable wireless devices.

For engineers reviewing the AP7315D-18W5-7 datasheet, AP7315D-18W5-7 pinout, AP7315D-18W5-7 application, or AP7315D-18W5-7 equivalent, this page provides verified technical context, package-specific pin functions, design-meaningful specifications, real-world use scenarios, and validated alternative options for low-noise, high-PSRR LDO selection in space-constrained portable electronics.

Technical Context

The AP7315D-18W5-7 integrates a CMOS-based error amplifier, precision voltage reference, current-limit circuit, and active discharge path activated during shutdown. Its internal architecture enables fast load transient response (<100µs settling) and maintains regulation down to 210mV dropout at 150mA for V_OUT = 1.8V.

Unlike non-discharge variants (e.g., AP7315-18W5-7), the "D" suffix denotes an integrated N-channel MOSFET (R_ON = 30Ω typical) between V_OUT and GND, ensuring rapid output discharge when EN is pulled low-critical for sequencing-sensitive RF and camera modules.

Key Specifications

Pinout & Package

SOT25 (5-pin, 2.9mm × 2.8mm × 1.3mm) package with thermal pad exposed on bottom for enhanced heat dissipation. Pin 4 is NC (not connected); recommended to tie to GND for improved thermal performance and EMI suppression.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with AP7315-18W5-7, the AP7315D-18W5-7 adds critical discharge functionality without sacrificing noise or PSRR; versus XC6210B182MR-G, it trades 15dB PSRR for guaranteed discharge behavior essential in RF and imaging subsystems.

Availability

AP7315D-18W5-7 is available at Aetrix Electronics and suitable for RF power amplifiers, camera sensor supplies, wireless adapter I/O interfaces, and portable media player audio codecs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AP7315D-18W5-7 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global semiconductor company specializing in discrete, analog, and mixed-signal ICs, with manufacturing certified to IATF 16949 and product definitions aligned to AEC-Q standards.

The AP7315 series belongs to Diodes' high-PSRR, low-noise LDO product line, engineered specifically for noise-sensitive portable electronics including smartphones, tablets, and wireless communication modules.

FAQ

What is the purpose of the NC pin (Pin 4) in the SOT25 package?

Pin 4 is not internally connected and serves no electrical function. Diodes Incorporated recommends connecting it to GND on the PCB to improve thermal dissipation via the copper pour and reduce electromagnetic interference coupling through parasitic capacitance. Leaving it floating may degrade thermal performance and increase susceptibility to noise.

Does AP7315D-18W5-7 require an external discharge resistor?

No. The "D" suffix indicates an integrated N-channel MOSFET (R_ON = 30Ω typical) that actively discharges V_OUT to GND when EN is low. This eliminates the need for external resistors, saves board space, and ensures consistent discharge timing across temperature and process variation-critical for reliable power sequencing in RF and imaging applications.

Can AP7315D-18W5-7 operate with input voltage below 1.8V?

Yes-its minimum input voltage is 1.7V, enabling operation during deep battery discharge (e.g., Li-ion at ~3.0V nominal, sagging to 2.8V). However, dropout voltage rises sharply below VIN = VOUT + 0.3V; at VIN = 1.75V, the device sustains 150mA only if VOUT drops slightly below 1.8V due to regulation loss, per the 2% dropout definition in the datasheet.

How does the 60µVrms output noise specification impact RF applications?

This noise level-measured over 10Hz–100kHz-is low enough to avoid degrading phase noise in local oscillators or increasing bit error rates in high-order QAM modems. In practice, it enables direct powering of RF transceiver VDDIO rails without additional LC filtering, reducing BOM count and PCB area while maintaining EVM compliance in 802.11n/ac systems.