Diodes Incorporated AP7331-18SNG-7

Overview

AP7331-18SNG-7 from Diodes Incorporated is a fixed-output 1.8V, 300mA low-dropout linear regulator in DFN2020-6 package with 65μA quiescent current, 300mV typical 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 wireless LAN cards and portable computing systems requiring stable low-power voltage regulation.

For engineers reviewing the AP7331-18SNG-7 datasheet, AP7331-18SNG-7 pinout, AP7331-18SNG-7 application, or AP7331-18SNG-7 equivalent, key selection criteria include its 1.8V fixed output, DFN2020-6 footprint compatibility, 65μA IQ across load, PSRR of 65dB at 100Hz, and stability with 1μF ceramic output capacitor - critical for space-constrained, low-noise embedded power rails.

Technical Context

The AP7331-18SNG-7 implements a PMOS pass transistor architecture enabling ultra-low dropout (300mV @ 300mA) and near-constant 65μA quiescent current across 2V–6V input range. Its internal 0.4V bandgap reference and error amplifier deliver ±2% output accuracy over –40°C to +85°C ambient.

Enable logic operates with VIH = 1.4V and VIL = 0.4V, supporting direct microcontroller GPIO control. Protection circuitry includes foldback current limiting (400–600mA), short-circuit clamping (~100mA), and thermal shutdown at 140°C with 15°C hysteresis - all fully integrated without external components.

Key Specifications

Pinout & Package

AP7331-18SNG-7 uses the DFN2020-6 (2.0mm × 2.0mm, 0.65mm pitch) thermally enhanced package with exposed thermal pad. Pin 1 is marked by dot; top-view pin numbering matches datasheet Figure 1c.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output LDO applications.

Compared with MCP1700-1802E/TO and XC6206P182MR-G, AP7331-18SNG-7 uniquely balances 300mA delivery, 65μA IQ, 80μs startup, and integrated EN - making it optimal for battery-powered systems needing both high peak current and aggressive power-state transitions.

Availability

AP7331-18SNG-7 is available at Aetrix Electronics and suitable for wireless LAN modules, notebook computer subsystems, battery-powered IoT sensors, and XDSL customer premises equipment requiring stable component supply with consistent DFN2020-6 packaging and RoHS-compliant green molding compound.

Supply support for AP7331-18SNG-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 communications markets.

The AP7331 series belongs to Diodes' precision low-dropout regulator product line, engineered specifically for space-constrained, battery-operated applications demanding ultra-low quiescent current, fast transient response, and robust fault protection without external components.

FAQ

What is the minimum input voltage required for AP7331-18SNG-7 to maintain 1.8V output at 300mA?

The AP7331-18SNG-7 requires a minimum input voltage of 2.1V to sustain 1.8V output at 300mA load, based on its typical 300mV dropout voltage specification. At lower inputs (e.g., 2.05V), output may drop below 1.8V due to process variation; design margin should target ≥2.15V for guaranteed regulation across temperature and tolerance.

Can AP7331-18SNG-7 operate without an output capacitor?

No - AP7331-18SNG-7 requires a minimum 1μF ceramic output capacitor (X5R/X7R, 10–200mΩ ESR) for stability and transient performance. Omitting it causes oscillation and uncontrolled overshoot/undershoot during load steps; the device is not internally compensated for zero-capacitance operation.

Is the EN pin 5V-tolerant when used with a 3.3V microcontroller GPIO?

Yes - the EN pin accepts up to VIN + 0.3V per absolute maximum ratings, and VIH is specified at 1.4V. A 3.3V GPIO easily exceeds the 1.4V threshold while staying well below the 7V absolute max input voltage, making it directly compatible without level-shifting.

How does thermal shutdown behave under sustained 300mA load at 70°C ambient?

With θ_JA = 167°C/W and 300mA at 1.8V (0.54W dissipation), junction temperature rise is ~90°C above ambient. At 70°C ambient, T_J ≈ 160°C - exceeding the 140°C shutdown threshold. Therefore, derating to ≤220mA or improving PCB copper area is required for continuous 300mA operation at 70°C.