Diodes Incorporated AP7331-SNG-7

Overview

AP7331-SNG-7 from Diodes Incorporated is a 300mA adjustable-output low-dropout linear regulator in DFN2020-6 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 wireless LAN cards and portable computing systems requiring stable low-power voltage regulation.

For engineers reviewing the AP7331-SNG-7 datasheet, AP7331-SNG-7 pinout, AP7331-SNG-7 application, or AP7331-SNG-7 equivalent, key selection criteria include its fixed/adjustable output flexibility (0.8V–5.0V), compatibility with 1μF ceramic output capacitors, PSRR of 65dB at 100Hz, and operation across –40°C to +85°C ambient temperature.

Technical Context

The AP7331-SNG-7 implements a band-gap referenced error amplifier driving an NMOS pass transistor, with internal 0.4V reference voltage and adjustable output via external resistor divider. Its architecture enables stable regulation with ultra-low quiescent current across input voltages from 2V to 6V.

Thermal shutdown triggers at ~140°C junction temperature with 15°C hysteresis, while current limit activates at ~400–600mA and short-circuit protection clamps output to ~100mA when V_OUT < 0.2V. EN pin logic thresholds are V_IL ≤ 0.4V and V_IH ≥ 1.4V, supporting direct microcontroller GPIO interfacing.

Key Specifications

Pinout & Package

AP7331-SNG-7 uses the DFN2020-6 package (2.0mm × 2.0mm × 0.6mm, 0.65mm pitch), RoHS-compliant and halogen-free, with exposed thermal pad for enhanced power dissipation (θ_JA = 167°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-quiescent-current LDO applications.

Compared with MCP1700T-3302E/MB and TPL7407LDR, AP7331-SNG-7 uniquely balances 300mA drive strength, 65μA IQ, adjustable output, and compact DFN2020-6 packaging-making it optimal for space-constrained, battery-sensitive wireless and portable computing applications where both flexibility and efficiency are required.

Availability

AP7331-SNG-7 is available at Aetrix Electronics and suitable for wireless LAN cards, XDSL routers, notebook computer subsystems, and battery-powered test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AP7331-SNG-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 belongs to Diodes' low-dropout linear regulator product line, engineered specifically for portable and battery-operated applications demanding ultra-low quiescent current, fast transient response, and robust fault protection in miniature packages.

FAQ

What is the minimum output capacitor value required for stability with AP7331-SNG-7?

The AP7331-SNG-7 is stable with a minimum 1μF X7R or X5R ceramic output capacitor (ESR 10–200mΩ). Lower ESR values improve transient response, while capacitance up to 4.7μF further reduces output voltage deviation during load steps. Placement within 2mm of OUT and GND pins is mandatory for optimal performance.

Can AP7331-SNG-7 be used in adjustable mode with a 0.8V output?

Yes. With V_REF = 0.4V, setting R2 = 100kΩ and R1 = 100kΩ yields V_OUT = 0.4V × (1 + 100k/100k) = 0.8V. R2 must remain ≤125kΩ to ensure reference stability; standard 1% metal-film resistors meet this requirement and provide ±2% total output accuracy across temperature.

How does thermal shutdown behave under sustained overload conditions?

When junction temperature reaches ~140°C, thermal shutdown disables the pass transistor. Output resumes once temperature falls to ~125°C due to 15°C hysteresis. Under continuous overload (e.g., 300mA into short), the device cycles on/off - limiting average power dissipation and preventing permanent damage, though system-level current limiting is still recommended.

Is the NC pin (Pin 5) safe to tie to GND for improved thermal conduction?

No. Pin 5 is internally unconnected and must remain electrically floating. Grounding it may cause unpredictable behavior or latch-up. Thermal performance relies solely on the exposed thermal pad (connected to GND) and proper PCB copper area - not NC pin routing. Refer to Diodes' AP02001 pad layout for verified thermal design.