Diodes Incorporated AP7315D-29FS4-7B

Overview

AP7315D-29FS4-7B from Diodes Incorporated is a 2.9V fixed-output, 150mA 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 ultra-low quiescent current (35µA typ) for RF supply and portable media applications.

For engineers reviewing the AP7315D-29FS4-7B datasheet, AP7315D-29FS4-7B pinout, AP7315D-29FS4-7B application, or AP7315D-29FS4-7B equivalent, this page provides verified technical context, package-specific pin functions, real-world use cases in battery-powered RF subsystems, and validated alternative options with documented functional differences.

Technical Context

The AP7315D-29FS4-7B integrates a CMOS-based error amplifier, precision voltage reference, current-limit circuit, and active discharge path (enabled when EN = low). Its architecture supports fast load transient response (<100µs settling) and stable operation with 0.47µF ceramic input/output capacitors.

This variant includes an internal 30Ω N-channel discharge FET (activated during shutdown), reducing VOUT decay time to <100µs under 150mA load-critical for sequencing-sensitive RF power domains where residual voltage must clear before next-stage activation.

Key Specifications

Pinout & Package

X2-DFN1010-4 (1.0mm × 1.0mm, 0.4mm pitch) package with exposed thermal pad. Requires GND-connected copper pour beneath the pad for thermal dissipation; pad must not serve as primary GND electrode.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP7315-29FS4-7B, the D-suffix version adds critical discharge functionality for sequenced power domains, while MCP1700T trades PSRR and noise performance for lower IQ-making AP7315D-29FS4-7B the sole option meeting both 75dB PSRR and active discharge in X2-DFN1010-4.

Availability

AP7315D-29FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier bias, camera sensor core supply, wireless adapter PHY rail, and portable media player audio codec applications requiring stable component supply, full traceability, and long-term lifecycle support.

Supply support for AP7315D-29FS4-7B 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 manufacturer of discrete semiconductors and analog ICs, specializing in high-efficiency power management, signal integrity, and protection solutions for consumer, industrial, and automotive markets.

The AP7315 series targets space-constrained, battery-operated devices requiring ultra-low noise and high PSRR-designed specifically for RF, imaging, and portable multimedia subsystems where power integrity directly impacts signal fidelity.

FAQ

What is the thermal pad connection requirement for AP7315D-29FS4-7B?

The exposed thermal pad is not electrically connected but must be soldered to a dedicated GND copper pour on the PCB. Use ≥4 thermal vias (0.3mm diameter) connecting the pad to an internal GND plane to achieve θ_JA ≤ 180°C/W. Do not rely on the pad as the sole GND connection for current return paths.

Does AP7315D-29FS4-7B require an external discharge resistor?

No. The 'D' suffix denotes integrated discharge functionality: when EN is pulled low, a 30Ω internal N-channel FET actively discharges VOUT to GND. This eliminates need for external resistors, saving board space and ensuring predictable decay time (<100µs at 150mA load).

Can AP7315D-29FS4-7B operate with input voltage below 2.9V?

Yes-minimum input is 1.7V, but dropout voltage rises with load. At 150mA output, dropout is 210mV; thus, VIN must be ≥3.11V to maintain regulated 2.9V. Below that, output drops linearly (e.g., VIN = 3.0V yields ~2.79V out), which may violate downstream device V_MIN requirements.

How does the 60µV_rms noise specification impact RF applications?

This noise level-measured over 10Hz–100kHz-directly limits phase noise in local oscillators powered by AP7315D-29FS4-7B. In 2.4GHz Bluetooth transceivers, it contributes <−145dBc/Hz close-in phase noise, enabling compliance with BLE 5.0 spectral mask requirements without additional filtering.