Diodes Incorporated AP7315D-23FS4-7B

Overview

AP7315D-23FS4-7B from Diodes Incorporated is a 2.3V fixed-output, 150mA low-dropout linear regulator with high PSRR (75dB at 1kHz), ultra-low output noise (60µVrms, 10Hz–100kHz), and 35µA quiescent current. It features an enable pin for power sequencing, ±1% output voltage accuracy over temperature, and is optimized for RF supply rails in portable wireless devices.

For engineers reviewing the AP7315D-23FS4-7B datasheet, AP7315D-23FS4-7B pinout, AP7315D-23FS4-7B application, or AP7315D-23FS4-7B equivalent, this LDO delivers stable 2.3V biasing under fast load transients, supports compact PCB layouts via X2-DFN1010-4 packaging, and enables low-noise analog/RF subsystems without external compensation.

Technical Context

The AP7315D-23FS4-7B integrates a CMOS-based error amplifier, precision voltage reference, current-limit circuit, and active discharge path (enabled when EN = low). Its architecture ensures fast transient response (<100µs settling) and maintains regulation down to 1.7V input across –40°C to +85°C ambient.

Unlike non-discharge variants, the "D" suffix denotes integrated NMOS discharge transistor (RON ≈ 30Ω) that actively pulls VOUT to GND during shutdown-critical for preventing back-powering in multi-rail systems. Input-to-output dropout is 340mV typical at 150mA for VOUT = 2.3V.

Key Specifications

Pinout & Package

AP7315D-23FS4-7B uses the X2-DFN1010-4 package (1.0mm × 1.0mm, 0.4mm pitch), featuring a thermal pad (exposed copper on underside) for enhanced heat dissipation. The package supports high-density routing and requires solder paste stencil design per Diodes' DFN guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-2302E/MB and XC6210B232MR-G, the AP7315D-23FS4-7B uniquely combines 75dB PSRR, 60µVrms noise, and active discharge in a 1.0mm² footprint - making it optimal for space-constrained, noise-sensitive, and multi-rail portable RF systems.

Availability

AP7315D-23FS4-7B is available at Aetrix Electronics and suitable for RF power amplifiers, wireless camera sensors, BLE SoC I/O domains, and portable media player audio codecs requiring stable component supply, long-term lifecycle support, and RoHS-compliant green packaging.

Supply support for AP7315D-23FS4-7B 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 ICs for power management, signal integrity, and connectivity applications.

The AP7315 series belongs to Diodes' high-performance LDO portfolio, engineered specifically for noise-sensitive portable electronics where small size, low IQ, and robust transient response are mandatory.

FAQ

What is the purpose of the thermal pad on the AP7315D-23FS4-7B 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 dedicated GND-connected copper pour on the PCB to dissipate up to 400mW of power and maintain junction temperature below 125°C. Leaving it unconnected or floating degrades thermal performance and risks thermal shutdown.

Does the AP7315D-23FS4-7B require an external output capacitor, and what type is recommended?

Yes, a minimum 0.47µF ceramic capacitor is required between VOUT and GND for stability and transient response. X5R or X7R dielectrics with low ESR (<10mΩ) are recommended. For loads with >50mA step changes, adding a 4.7µF bulk tantalum or polymer capacitor in parallel improves regulation during large transients.

How does the "D" suffix in AP7315D-23FS4-7B affect functionality compared to non-D variants?

The "D" denotes integrated active discharge: when EN is pulled low, an internal 30Ω NMOS switch connects VOUT to GND, discharging output capacitance in <1ms. Non-D versions lack this feature and rely on load leakage or external resistors for discharge-making the "D" variant essential for systems requiring strict power-rail sequencing and zero residual voltage.

Can AP7315D-23FS4-7B operate from a 2.5V input while delivering 150mA at 2.3V?

Yes. With a 2.5V input, the dropout voltage is 340mV maximum at 150mA, resulting in a minimum headroom requirement of 0.34V. Since 2.5V − 2.3V = 0.2V < 0.34V, it cannot sustain 150mA continuously at 2.5V. However, it will regulate at reduced current (≈85mA) or enter dropout-confirm operation using the Dropout Voltage vs. Output Current curve on page 7 of DS38352 Rev. 2-2.