Diodes Incorporated AP7331-WG-7

Overview

AP7331-WG-7 from Diodes Incorporated is a 300mA adjustable/fixed-output low-dropout linear regulator in SOT25 package, featuring 65μA typical quiescent current, 300mV dropout at full load, and fast 80μs startup. It integrates enable control, thermal shutdown, current limiting, and short-circuit protection, and is optimized for battery-powered portable electronics requiring stable low-power voltage regulation.

For engineers reviewing the AP7331-WG-7 datasheet, AP7331-WG-7 pinout, AP7331-WG-7 application, or AP7331-WG-7 equivalent, key selection criteria include ultra-low IQ across load range, compatibility with 1μF ceramic output capacitors, fixed 3.3V output (per ordering code "33"), EN logic-level thresholds (VIH = 1.4V), and thermal shutdown at 140°C with 15°C hysteresis.

Technical Context

The AP7331-WG-7 implements a PMOS pass transistor architecture enabling low dropout and high PSRR (65dB at 100Hz). Its internal 0.4V bandgap reference feeds an error amplifier that regulates output via feedback (ADJ pin) or fixed resistor network, supporting both adjustable (0.8–5.0V) and factory-set outputs (e.g., 3.3V).

Enable functionality uses active-high logic with VIH ≥ 1.4V and VIL ≤ 0.4V; shutdown current is 1μA. Protection circuitry includes foldback current limiting (400–600mA), short-circuit clamping (~100mA), and thermal shutdown with automatic recovery at ~125°C junction temperature.

Key Specifications

Pinout & Package

SOT25 package (3.0mm × 1.7mm × 1.3mm), RoHS-compliant, green molding compound, lead-free finish.

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, AP7331-WG-7 uniquely balances ultra-low IQ (65μA), full protection set, EN control, and fast transient response-making it optimal for portable systems demanding both efficiency and robustness.

Availability

AP7331-WG-7 is available at Aetrix Electronics and suitable for wireless LAN cards, XDSL routers, and battery-powered equipment requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for AP7331-WG-7 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 industrial, computing, and consumer markets.

The AP7331 belongs to Diodes' low-quiescent-current LDO family, designed specifically for energy-constrained portable and battery-operated applications where extended runtime and fast dynamic response are essential.

FAQ

What output voltage does AP7331-WG-7 deliver?

AP7331-WG-7 delivers a fixed 3.3V output. The "33" in the ordering code (implied by "WG") specifies the 3.3V variant; it is not adjustable. Output accuracy is ±2% over –40°C to +85°C ambient, with line regulation of 0.01–0.20%/V and load regulation of ±0.6% from 1mA to 300mA.

Can AP7331-WG-7 operate with a 1µF ceramic output capacitor?

Yes - AP7331-WG-7 is explicitly characterized and guaranteed stable with a 1µF X7R or X5R ceramic output capacitor (ESR 10–200mΩ). This eliminates need for larger or higher-ESR capacitors, reducing cost and PCB footprint. Performance metrics like load transient response and PSRR are validated under this condition.

How does the EN pin function, and what are its voltage thresholds?

The EN pin is active-high with VIH ≥ 1.4V (minimum logic high) and VIL ≤ 0.4V (maximum logic low). When pulled high (≥1.4V), the regulator enables and delivers output; when pulled low (≤0.4V), it enters shutdown with 1μA input current. If unused, EN must be tied directly to IN to ensure continuous operation.

Does AP7331-WG-7 include thermal protection, and how does it behave?

Yes - AP7331-WG-7 incorporates thermal shutdown at approximately 140°C junction temperature, with automatic recovery when junction cools to ~125°C (15°C hysteresis). Under sustained overload, it cycles on/off to limit average power dissipation, protecting against permanent damage without requiring external intervention.