Diodes Incorporated AP7311-33WG-7

Overview

AP7311-33WG-7 from Diodes Incorporated is a fixed-output 3.3V, 150mA low-dropout linear regulator in SOT25 package, featuring 65µA quiescent current, 150mV dropout at full load, and 65dB PSRR at 100Hz. It integrates enable control, thermal shutdown, current limiting, and short-circuit protection - designed for battery-powered portable devices requiring stable, ultra-low-power voltage regulation.

For engineers reviewing the AP7311-33WG-7 datasheet, AP7311-33WG-7 pinout, AP7311-33WG-7 application, or AP7311-33WG-7 equivalent, key selection considerations include its fast 80µs startup time, stability with 1µF ceramic output capacitor, wide 2V–6V input range, -40°C to +85°C operating temperature, and fixed 3.3V output accuracy of ±2% over load and temperature.

Technical Context

The AP7311-33WG-7 implements a PMOS pass transistor architecture with internal 0.4V bandgap reference, enabling low dropout and minimal quiescent current across load (0–150mA) and input voltage (2–6V). Its error amplifier drives the gate of the pass element to maintain regulated output with high DC accuracy and fast transient response.

Enable logic operates with VIH ≥ 1.4V and VIL ≤ 0.4V; shutdown current is <1µA. Protection circuitry includes foldback current limiting (200–300mA), short-circuit clamping (~50mA), and thermal shutdown at ~140°C with 15°C hysteresis - all fully integrated without external components.

Key Specifications

Pinout & Package

SOT25 (5-pin, 2.9mm × 1.6mm × 1.1mm) surface-mount package with RoHS-compliant lead-free finish and green molding compound (no Br/Sb).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700-3302E/TO and TPS70633DBVR, AP7311-33WG-7 offers optimal balance of low dropout (150mV), moderate IQ (65µA), and minimal 1µF output capacitance - making it ideal for space-constrained, wide-input portable designs where both efficiency and simplicity matter.

Availability

AP7311-33WG-7 is available at Aetrix Electronics and suitable for wireless sensor nodes, GSM baseband power supplies, USB peripherals, and industrial I/O modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AP7311-33WG-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 AP7311 belongs to Diodes' low-quiescent-current LDO family, engineered specifically for battery-powered and energy-conscious applications demanding fast transient response, minimal external components, and robust fault protection.

FAQ

What is the minimum input voltage required to maintain 3.3V output at 150mA load?

The AP7311-33WG-7 has a typical dropout voltage of 150mV at 150mA, so the minimum input voltage is 3.3V + 0.15V = 3.45V. This ensures regulation remains within specification across temperature and process variation; datasheet confirms stable operation down to VIN = VOUT + 0.3V under worst-case conditions.

Can the EN pin be left unconnected, or must it be tied high?

The EN pin must not be left floating - it has no internal pull-up. To ensure reliable operation, tie EN directly to IN for always-on use, or drive it actively with a logic signal meeting VIH ≥ 1.4V and VIL ≤ 0.4V. Floating EN may cause erratic enable/disable behavior due to noise coupling.

Is a minimum load required for output stability?

No minimum load is required. The AP7311-33WG-7 remains stable and regulated from 0mA to 150mA, including no-load conditions. This is confirmed in the datasheet's "No Load Stability" section and validated by stability testing with 1µF ceramic output capacitor.

Does the device require an input capacitor, and what value is recommended?

Yes - a minimum 1µF X5R/X7R ceramic capacitor is required between IN and GND, placed as close as possible to the pins. Larger values improve noise rejection and transient immunity; the datasheet states input capacitance "may be increased without limit," and layout guidelines emphasize low-inductance placement using wide copper traces.