Diodes Incorporated AP7315D-22FS4-7B

Overview

AP7315D-22FS4-7B from Diodes Incorporated is a 2.2V fixed-output, 150mA low-dropout linear regulator with high PSRR (75dB at 1kHz), ultra-low output noise (60µVrms), ±1% output voltage accuracy, and enable-controlled shutdown. It operates from 1.7V to 5.25V input and delivers stable power to noise-sensitive RF supply rails in portable wireless devices.

For engineers reviewing the AP7315D-22FS4-7B datasheet, AP7315D-22FS4-7B pinout, AP7315D-22FS4-7B application, or AP7315D-22FS4-7B equivalent, this page provides verified technical context, package-specific pin functions, real-world use cases for RF and camera subsystems, and validated alternative LDOs with documented functional trade-offs.

Technical Context

The AP7315D-22FS4-7B 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 maintains regulation down to 280mV dropout at 150mA for 2.2V output.

Unlike non-discharge variants (e.g., AP7315-22FS4-7B), the "D" suffix denotes integrated NMOS discharge transistor (RON ≈ 30Ω) that actively pulls VOUT to GND when EN is low-critical for preventing back-powering in multi-rail systems and meeting strict power sequencing requirements.

Key Specifications

Pinout & Package

AP7315D-22FS4-7B uses the X2-DFN1010-4 (1.0mm × 1.0mm, 0.4mm pitch) package with wettable flank leads for automated optical inspection. Thermal pad (exposed bottom) must be connected to PCB ground plane for thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-2202E/TT and XC6210B222MR-G, the AP7315D-22FS4-7B uniquely combines 75dB PSRR, 60µVrms noise, and guaranteed 30Ω discharge resistance in a 1.0×1.0mm DFN-making it optimal for RF-critical, space-constrained portable designs requiring strict power sequencing.

Availability

AP7315D-22FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier bias, CMOS image sensor analog supply, and BLE SoC core voltage applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant green packaging.

Supply support for AP7315D-22FS4-7B 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 solutions for power management, signal integrity, and connectivity applications.

The AP7315 series belongs to Diodes' high-performance LDO portfolio designed specifically for battery-powered portable electronics demanding ultra-low noise, high PSRR, and precise voltage regulation in minimal footprints.

FAQ

What is the purpose of the NC pin (Pin 5) on the X2-DFN1010-4 package?

Pin 5 is internally not connected and serves no electrical function. Diodes recommends connecting it to PCB ground to maximize copper area for thermal conduction and improve EMI shielding-this does not alter regulation performance but enhances thermal reliability under sustained 150mA load.

How does the active discharge feature behave during EN pin deactivation?

When EN transitions from HIGH to LOW, the internal 30Ω NMOS discharge FET turns ON and sinks current from VOUT to GND until VOUT drops below ~0.2V. This occurs within 1ms for a 1µF output capacitor and prevents back-powering of upstream circuits or latch-up in multi-rail systems.

Can AP7315D-22FS4-7B operate with only a 0.22µF output capacitor?

No. The datasheet specifies minimum 0.47µF ceramic output capacitance for stability and transient response. Using 0.22µF risks oscillation under load steps and violates the ESR vs. IOUT stability boundary shown in Figure 11-designs must adhere to the 0.47µF minimum with X5R/X7R dielectric.

Is the thermal pad electrically connected to GND inside the AP7315D-22FS4-7B die?

Yes-the exposed thermal pad is internally bonded to the silicon substrate's ground reference and must be soldered to a PCB ground plane. It is not an isolated thermal slug; using it as a standalone heatsink without GND connection compromises both thermal performance and electrical noise immunity.