Diodes Incorporated AP7315-28FS4-7B

Overview

AP7315-28FS4-7B from Diodes Incorporated is a 2.8V fixed-output, 150mA low-dropout linear regulator with ±1% output voltage accuracy, 75dB PSRR at 1kHz, 60µVrms output noise (10Hz–100kHz), and 35µA quiescent current. It features CMOS-based architecture, enable control, and is optimized for RF supply and portable media applications requiring stable, low-noise biasing.

For engineers reviewing the AP7315-28FS4-7B datasheet, AP7315-28FS4-7B pinout, AP7315-28FS4-7B application, or AP7315-28FS4-7B equivalent, this LDO delivers high PSRR and ultra-low noise in a 1.0mm × 1.0mm X2-DFN1010-4 package - critical for space-constrained, battery-powered systems where power integrity and thermal efficiency are design priorities.

Technical Context

The AP7315-28FS4-7B integrates a precision voltage reference, error amplifier, current-limit circuit, and CMOS pass transistor to achieve 2.8V regulation across 1.7V–5.25V input range. Its non-discharge architecture maintains output voltage during shutdown without sinking load capacitance.

Designed for fast transient response and minimal board area, it operates stably with 0.47µF ceramic input/output capacitors and supports enable-driven sequencing. Dropout voltage is 210mV typical at 150mA (VIN ≥ 3.01V), enabling efficient operation near battery end-of-life.

Key Specifications

Pinout & Package

AP7315-28FS4-7B uses the X2-DFN1010-4 (1.0mm × 1.0mm, 0.4mm pitch) package with exposed thermal pad. PCB layout requires large copper area under the thermal pad connected to GND for optimal thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700-2802E/TO and XC6219B282MR-G, the AP7315-28FS4-7B uniquely balances 75dB PSRR, 60µVrms noise, 35µA IQ, and active-high EN in a 1.0mm² footprint - making it the only option meeting simultaneous RF bias, battery life, and sequencing requirements in modern portable designs.

Availability

AP7315-28FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier bias, camera sensor core supply, portable media player audio codec, and wireless adapter baseband IC applications requiring stable component supply, long-term manufacturability, and RoHS-compliant sourcing.

Supply support for AP7315-28FS4-7B 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 semiconductor company specializing in discrete, analog, and mixed-signal devices, with leadership in power management, signal integrity, and protection solutions.

The AP7315 series belongs to Diodes' high-performance LDO portfolio, designed specifically for battery-powered portable electronics demanding ultra-low noise, high PSRR, and minimal footprint - targeting smartphone, tablet, and wireless connectivity markets.

FAQ

What is the maximum allowable input voltage for AP7315-28FS4-7B?

The absolute maximum input voltage is 6.0V, but the recommended operating range is 1.7V to 5.25V. Exceeding 5.25V risks violating safe operating area limits and may trigger internal protection or cause permanent damage. For reliable operation with margin, VIN should remain ≤5.0V in production designs.

Does AP7315-28FS4-7B include output discharge functionality?

No - AP7315-28FS4-7B is the non-discharge variant (as indicated by absence of "D" in the part number). When disabled via EN pin, the output remains floating and does not actively sink load capacitance. For automatic discharge, select AP7315D-28FS4-7B, which integrates an internal NMOS discharge switch (RON ≈30Ω).

Can AP7315-28FS4-7B operate with ceramic capacitors smaller than 0.47µF?

No - the datasheet specifies 0.47µF as the minimum stable ceramic output capacitance. Using smaller values (e.g., 0.22µF) risks instability, overshoot, or oscillation under load transients. Input capacitance must also be ≥0.47µF ceramic, placed within 2mm of VIN/GND pins to ensure robust decoupling.

How does thermal performance differ between X2-DFN1010-4 and SOT23 packages?

The X2-DFN1010-4 package (used in AP7315-28FS4-7B) offers significantly better thermal resistance (θ_JA ≈ 220°C/W on JEDEC 2-layer board) versus SOT23 (θ_JA ≈ 280°C/W) due to its exposed thermal pad. With proper PCB copper pour connected to GND, junction temperature rise at 150mA is ~33°C - well below the 125°C limit - whereas SOT23 would exceed safe limits under identical conditions.