Diodes Incorporated AP7361C-33E-13

Overview

AP7361C-33E-13 from Diodes Incorporated is a 1A fixed-output (3.3V), ultra-low dropout linear regulator with enable, designed for power rail regulation in space-constrained, battery-sensitive systems. It delivers ±1% output accuracy, 360mV dropout at 1A, 60µA quiescent current, and integrates thermal shutdown, fold-back short-circuit protection (400mA), and current limit (1.5A).

For engineers reviewing the AP7361C-33E-13 datasheet, AP7361C-33E-13 pinout, AP7361C-33E-13 application, or AP7361C-33E-13 equivalent, key selection criteria include dropout voltage at full load, EN logic thresholds (VIH = 1.0V min, VIL = 0.3V max), stability with ≥2.2µF MLCC output capacitance, and thermal resistance (θJA = 100°C/W in SO-8EP package).

Technical Context

The AP7361C-33E-13 implements a PMOS pass transistor architecture enabling ultra-low dropout operation and high PSRR (75dB @ 1kHz). Its internal 0.8V bandgap reference and error amplifier regulate output via feedback from the fixed 3.3V output node-no external resistors required.

Enable control is implemented with active-high EN pin (1.0V min VIH, 0.3V max VIL) and 3.0MΩ internal pull-down resistor. Protection circuitry includes fold-back current limiting (400mA short-circuit clamp), thermal shutdown at 150°C with 20°C hysteresis, and over-temperature cycling behavior confirmed in thermal transient testing.

Key Specifications

Pinout & Package

AP7361C-33E-13 is packaged in SO-8EP (exposed pad), a thermally enhanced 8-pin surface-mount package with GND-connected thermal pad. Pin 1 = IN, Pin 2 = GND, Pin 3 = OUT, Pin 4 = GND, Pin 5 = EN, Pin 6 = NC, Pin 7 = NC, Pin 8 = GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700-3302E/TO and TLS850B2TE/V1, AP7361C-33E-13 uniquely balances 1A output, ultra-low dropout, enable control, and SO-8EP thermal performance - making it optimal for industrial and portable designs needing robust, medium-current regulation without automotive overhead.

Availability

AP7361C-33E-13 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, medical patient monitor displays, and set-top box HDMI interfaces requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AP7361C-33E-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 company specializing in discrete, analog, and mixed-signal solutions, with design centers in Asia, Europe, and the US, and manufacturing in ISO/TS 16949-certified facilities.

The AP7361C belongs to Diodes' high-performance LDO regulator product line, engineered for low-noise, low-dropout power management in portable, industrial, and consumer electronics where efficiency, thermal resilience, and small-footprint integration are critical.

FAQ

What is the minimum input voltage required for AP7361C-33E-13 to maintain regulation at 1A load?

The minimum input voltage is calculated as VOUT + VDROPOUT = 3.3V + 0.36V = 3.66V. At 1A load and +25°C, the typical dropout is 360mV; worst-case (max) dropout is 440mV per datasheet, so VIN ≥ 3.74V ensures regulation across temperature and process variation. Input below 3.66V causes output collapse.

Can AP7361C-33E-13 operate without an output capacitor?

No. The datasheet explicitly requires ≥2.2µF ceramic output capacitance for stability. Omitting COUT causes oscillation and potential device failure. The LDO's internal compensation relies on the ESR and capacitance of this external capacitor; tantalum or aluminum electrolytic types may be used but require higher values due to higher ESR.

Is the EN pin internally pulled down, and what happens if left unconnected?

Yes - the EN pin has a 3.0MΩ internal pull-down resistor. If left unconnected, the pin defaults to logic low, disabling the regulator output. To ensure reliable turn-on, drive EN to ≥1.0V using a GPIO or connect directly to VIN through a current-limiting resistor (e.g., 10kΩ) if always-on operation is needed.

How does thermal performance differ between SO-8EP and U-DFN3030-8 packages for AP7361C-33E-13?

SO-8EP has θJA = 100°C/W; U-DFN3030-8 (Type E) has θJA = 70°C/W - a 30°C/W improvement due to its smaller footprint and superior thermal pad soldering. For 1A load at 3.66V input, power dissipation is 360mW; SO-8EP junction rise is ~36°C above ambient, while U-DFN3030-8 rises only ~25°C - enabling higher ambient operation or reduced heatsinking.