Diodes Incorporated AP7315D-25FS4-7B

Overview

AP7315D-25FS4-7B from Diodes Incorporated is a 2.5V 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). Fabricated on a CMOS process, it delivers high power supply rejection and ultra-low quiescent current (35µA typ.) for noise-sensitive RF and portable media subsystems.

For engineers reviewing the AP7315D-25FS4-7B datasheet, AP7315D-25FS4-7B pinout, AP7315D-25FS4-7B application, or AP7315D-25FS4-7B equivalent, key selection criteria include dropout voltage (280mV max at 150mA), EN logic thresholds (0.5V low / 1.3V high), thermal performance in X2-DFN1010-4, and discharge functionality for fast VOUT decay during shutdown.

Technical Context

The AP7315D-25FS4-7B integrates a precision voltage reference, error amplifier, current-limit circuit, and NMOS pass transistor with built-in auto-discharge path. Its CMOS architecture enables stable operation with 0.47µF ceramic input/output capacitors and supports rapid load transient response under 150mA step changes.

Unlike non-discharge variants (e.g., AP7315-25FS4-7B), the "D" suffix denotes an internal 30Ω discharge FET between VOUT and GND when EN = low, reducing output decay time without external components. This feature is critical for sequencing-sensitive systems requiring controlled power-down behavior.

Key Specifications

Pinout & Package

AP7315D-25FS4-7B uses the X2-DFN1010-4 (1.0mm × 1.0mm, 0.4mm pitch) package with wettable flank leads for automated optical inspection. The thermal pad (exposed bottom) must be connected to PCB ground plane 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 MCP1700-2502E/TO and XC6219B252MR-G, AP7315D-25FS4-7B uniquely combines 2.5V precision, integrated discharge, and 1.0mm² footprint-enabling compact, sequenced power architectures without added BOM cost or layout complexity.

Availability

AP7315D-25FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier bias, mobile camera sensor core supply, and portable media player audio codec applications requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for AP7315D-25FS4-7B 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-reliability power management, signal integrity, and protection solutions for consumer, industrial, and automotive markets.

The AP7315 series belongs to Diodes' precision LDO portfolio, engineered specifically for space-constrained, battery-powered devices demanding ultra-low noise, high PSRR, and fast enable/disable control in sub-2mm² packages.

FAQ

What is the purpose of the "D" suffix in AP7315D-25FS4-7B?

The "D" denotes integrated auto-discharge functionality: when the EN pin is pulled low, an internal 30Ω FET actively discharges the VOUT capacitor to GND. This eliminates residual voltage hold-up, enabling precise power sequencing in multi-rail systems without external discharge resistors or FETs.

Can AP7315D-25FS4-7B operate with input voltage below 2.5V?

Yes - its minimum input voltage is 1.7V, but regulation requires VIN ≥ VOUT + dropout voltage. At 150mA, dropout is up to 280mV, so VIN must be ≥ 2.78V to sustain 2.5V output. Below that, output drops linearly per the dropout curve in the datasheet.

Is the thermal pad electrically connected internally?

No - the exposed thermal pad on the X2-DFN1010-4 package is not internally connected to any circuit node. It must be soldered to a PCB copper area tied to GND for thermal conduction, but should not serve as the sole GND connection; dedicated GND pin (Pin 2) remains the primary return path.

How does PSRR performance change with load current?

PSRR degrades slightly with increasing load: the datasheet specifies 75dB at 1kHz with 30mA load, but drops to ~70dB at 150mA due to reduced loop gain. For critical noise rejection, maintain load currents ≤50mA or add downstream LC filtering where PSRR margin is insufficient.