Diodes Incorporated AP7361-33ER-13

Overview

AP7361-33ER-13 from Diodes Incorporated is a 1A fixed-output (3.3V) ultra-low dropout linear regulator in SOT223R package with enable control, 70µA quiescent current, and 500mV dropout at full load. It integrates current limiting, thermal shutdown, and stable operation with ≥2.2µF ceramic output capacitors-designed for FPGA I/O power, laptop subsystems, and battery-powered audio devices.

For engineers reviewing the AP7361-33ER-13 datasheet, AP7361-33ER-13 pinout, AP7361-33ER-13 application, or AP7361-33ER-13 equivalent, key selection criteria include dropout voltage at 1A load, EN pin logic thresholds, thermal resistance (110°C/W), output accuracy (±2% over temperature), and compatibility with low-ESR ceramic capacitors.

Technical Context

The AP7361-33ER-13 implements a PMOS pass transistor architecture enabling ultra-low dropout (500mV @ 1A) and fast transient response. Its internal 0.8V bandgap reference feeds an error amplifier that regulates output via feedback from the fixed 3.3V output node-no external resistors required.

Enable functionality is implemented as a logic-high active input (VIH ≥ 1.0V) with sub-1µA shutdown current. Protection circuitry includes foldback current limiting (1.1–1.5A trip range) and thermal shutdown with 20°C hysteresis, triggered at ~150°C junction temperature.

Key Specifications

Pinout & Package

SOT223R package: thermally enhanced surface-mount variant with exposed thermal pad; pin 1 = GND, pin 2 = OUT, pin 3 = IN. Pin 4 is NC (no connection).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1703T-3302E/MB and XC6210B332MR-G, the AP7361-33ER-13 uniquely delivers 1A capability with integrated thermal shutdown, 500mV dropout at full load, and 65dB PSRR-making it the only option qualified for thermally demanding, high-current digital I/O applications requiring safety-critical protection.

Availability

AP7361-33ER-13 is available at Aetrix Electronics and suitable for FPGA I/O power, laptop subsystem regulation, and portable audio codec supply requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AP7361-33ER-13 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 semiconductor manufacturer specializing in discrete, analog, and mixed-signal solutions for power management, signal integrity, and connectivity applications.

The AP7361 belongs to Diodes' high-performance LDO family targeting low-noise, high-current power delivery in computing, consumer, and industrial systems-designed specifically for applications demanding ultra-low dropout and fast transient response.

FAQ

What is the minimum input voltage required for stable 3.3V output at 1A?

The AP7361-33ER-13 requires VIN ≥ 3.8V to maintain regulation at 1A load, based on its 500mV dropout specification. Below this, output voltage collapses proportionally; operation below 2.2V input is prohibited per absolute maximum ratings.

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

The EN pin must never be left floating-it has no internal pull-up. For always-on operation, tie EN directly to IN. For controlled enable/disable, drive with a logic signal meeting VIH ≥ 1.0V and VIL ≤ 0.3V, with source impedance <10kΩ to avoid false triggering.

Is the SOT223R package thermally equivalent to standard SOT223?

No. The SOT223R pinout swaps IN and GND positions (GND=Pin1, OUT=Pin2, IN=Pin3), altering PCB layout and thermal path. Its θJA remains 110°C/W, but thermal pad soldering must follow Diodes' recommended footprint for SOT223R-not generic SOT223 land patterns.

Does the AP7361-33ER-13 require an external resistor divider for 3.3V output?

No. The "33" suffix denotes factory-trimmed fixed 3.3V output; ADJ pin is not present in this variant. External resistors are only used in adjustable versions (e.g., AP7361-ADJ), which are unavailable in SOT223R packaging.