Diodes Incorporated AP7315-33FS4-7B

Overview

AP7315-33FS4-7B from Diodes Incorporated is a 3.3V fixed-output, 150mA low-dropout linear regulator with ±1% output voltage accuracy, 75dB PSRR at 1kHz, 60µV_rms output noise (10Hz–100kHz), and 35µA quiescent current. It features enable control, CMOS-based architecture, and is optimized for RF supply rails in space-constrained portable electronics.

For engineers reviewing the AP7315-33FS4-7B datasheet, AP7315-33FS4-7B pinout, AP7315-33FS4-7B application, or AP7315-33FS4-7B equivalent, this page delivers verified electrical specs, package mapping to X2-DFN1010-4, thermal pad layout guidance, and real-world use cases in RF power management, camera modules, and portable media subsystems.

Technical Context

The AP7315-33FS4-7B integrates a precision voltage reference, error amplifier, current-limit circuit, and CMOS pass transistor - enabling stable 3.3V regulation across 1.7V–5.25V input with dropout as low as 210mV at 150mA. Its non-discharge architecture avoids output discharge during shutdown, preserving downstream bias conditions.

EN pin logic thresholds (0.5V_IL, 1.3V_IH) ensure robust enable/disable control under varying supply conditions, while internal short-circuit protection limits output current to ~55mA when VOUT is shorted to GND - preventing thermal runaway without external components.

Key Specifications

Pinout & Package

X2-DFN1010-4 (1.0mm × 1.0mm, 0.4mm pitch) with exposed thermal pad - requires PCB copper area 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 MCP1700-3302E/TO and XC6206P332MR-G, the AP7315-33FS4-7B uniquely balances 75dB PSRR, 60µV_rms noise, 35µA IQ, and integrated enable in a 1.0mm² package - making it the only option meeting simultaneous RF-grade noise rejection and dynamic power control requirements.

Availability

AP7315-33FS4-7B is available at Aetrix Electronics and suitable for RF power supply, camera module bias, and portable media player core applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant green packaging.

Supply support for AP7315-33FS4-7B 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-performance power management, signal integrity, and protection solutions for consumer, industrial, and automotive markets.

The AP7315 series belongs to Diodes' high-PSRR, low-noise LDO portfolio - designed specifically for noise-sensitive applications in portable communications equipment where compact size and battery efficiency are critical.

FAQ

What is the maximum allowable input voltage for AP7315-33FS4-7B?

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 circuits. Operation above 5.25V is not guaranteed and reduces reliability margin per datasheet Section 4 (Absolute Maximum Ratings).

Does AP7315-33FS4-7B include output discharge functionality?

No - AP7315-33FS4-7B is the non-discharge variant (indicated by absence of "D" in part number). When disabled via EN pin, the output remains floating and retains its voltage until discharged by external load or leakage. For active discharge, select AP7315D-33FS4-7B, which integrates an NMOS discharge switch (R_DS(ON) ≈ 30Ω).

Can AP7315-33FS4-7B operate with ceramic capacitors smaller than 0.47µF?

The datasheet specifies 0.47µF as the minimum recommended value for both C_IN and C_OUT to ensure stability and transient response across temperature and load. Using smaller values risks instability, overshoot, or oscillation - especially under 100mA load steps. No derating or validation data is provided for <0.47µF ceramics.

How is thermal performance affected if the thermal pad is left unconnected?

Leaving the thermal pad unconnected increases junction-to-ambient thermal resistance (θ_JA) by ~120°C/W versus proper GND-connected copper pour, raising die temperature by >40°C at 150mA load. This violates SOA limits and accelerates parametric drift - the pad must be soldered to ≥100mm² GND copper area per datasheet Layout Considerations section.