Diodes Incorporated AP7315D-32FS4-7B

Overview

AP7315D-32FS4-7B from Diodes Incorporated is a 3.2V 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 stable power to RF supply rails in space-constrained portable devices.

For engineers reviewing the AP7315D-32FS4-7B datasheet, AP7315D-32FS4-7B pinout, AP7315D-32FS4-7B application, or AP7315D-32FS4-7B equivalent, key selection criteria include dropout voltage at 150mA (max 290mV), ultra-low quiescent current (35µA typ), EN pin logic thresholds (0.5V low / 1.3V high), and thermal performance in X2-DFN1010-4 package.

Technical Context

The AP7315D-32FS4-7B integrates a CMOS-based error amplifier, precision voltage reference, current-limit circuit, and active discharge path activated during shutdown. Its architecture enables fast load transient response (<100µs settling) and stable operation with 0.47µF ceramic output capacitors.

This variant includes an internal N-channel MOSFET (R_ON = 30Ω typ) between VOUT and GND for automatic output discharge when disabled, reducing residual voltage on downstream circuits. Input-to-output isolation remains >60dB across 10Hz–1MHz under 150mA load.

Key Specifications

Pinout & Package

X2-DFN1010-4 (1.0mm × 1.0mm, 0.4mm pitch) with exposed thermal pad - requires PCB copper pour connected to GND for optimal thermal dissipation (θ_JA = 220°C/W on JEDEC High-K board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-3202E/MB and XC6210B322MR-G, the AP7315D-32FS4-7B uniquely combines 3.2V precision, active discharge, and X2-DFN1010-4 footprint-enabling compact, fast-turnoff RF and imaging power domains where residual voltage must be actively cleared.

Availability

AP7315D-32FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier bias, camera sensor analog supply, wireless adapter core logic, and portable media player audio codec applications requiring stable component supply across production lifecycles.

Supply support for AP7315D-32FS4-7B 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 power management, signal integrity, and protection solutions for consumer, industrial, and automotive markets.

The AP7315 series targets portable electronics requiring ultra-low-noise, high-PSRR LDOs in minimal footprints - designed specifically for RF, imaging, and battery-sensitive applications where efficiency, size, and signal purity are critical.

FAQ

What is the purpose of the thermal pad on the AP7315D-32FS4-7B package?

The exposed thermal pad on the X2-DFN1010-4 package is a mechanical and thermal interface-not an electrical node. It must be soldered to a minimum 10mm² copper area connected to GND to dissipate heat and maintain junction temperature below 125°C at 150mA load. Leaving it unconnected reduces thermal performance by >40%.

Does the AP7315D-32FS4-7B require an input capacitor?

Yes-a minimum 0.47µF ceramic capacitor is required between VIN and GND, placed within 2mm of the pins. This stabilizes the input rail during load transients and prevents oscillation caused by source impedance. Larger values (e.g., 2.2µF) improve rejection of low-frequency ripple but are not mandatory for basic operation.

How does the active discharge function behave during shutdown?

When EN is pulled low, the internal 30Ω N-channel FET connects VOUT to GND, discharging output capacitance to <0.1V within 100µs. This prevents back-powering of upstream regulators or unintended wake-up of downstream logic. Discharge only occurs when EN is actively driven low-not during undervoltage lockout or thermal shutdown.

Can the AP7315D-32FS4-7B be used with ceramic output capacitors smaller than 0.47µF?

No-0.47µF is the minimum recommended value per Diodes' design validation. Smaller ceramics (e.g., 0.1µF) cause instability and ringing under load steps due to insufficient phase margin. The device's stability is guaranteed only with ≥0.47µF ceramic capacitors having ESR <100mΩ and placed adjacent to VOUT/GND pins.