Diodes Incorporated AP7361C-33D-13

Overview

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

For engineers reviewing the AP7361C-33D-13 datasheet, AP7361C-33D-13 pinout, AP7361C-33D-13 application, or AP7361C-33D-13 equivalent, key selection criteria include dropout voltage at full load, EN pin logic thresholds (VIH = 1.0V min, VIL = 0.3V max), thermal resistance (95°C/W for TO252), stability with ≥2.2µF MLCC output capacitors, and fixed 3.3V output configuration without external feedback resistors.

Technical Context

The AP7361C-33D-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 by comparing feedback from a fixed resistor network (for fixed versions) or adjustable divider (not used here).

Enable control is implemented via a dedicated EN pin with internal 3.0MΩ pull-down resistor and ±0.1µA leakage; activation requires VIH ≥ 1.0V. Protection circuitry includes fold-back current limiting (triggers at ~400mA during short-circuit) and thermal shutdown at +150°C with 20°C hysteresis.

Key Specifications

Pinout & Package

AP7361C-33D-13 uses the TO252 (DPAK) package: 3-pin surface-mount outline with exposed thermal pad, rated for 1250mW power dissipation and 95°C/W junction-to-ambient thermal resistance on standard 2oz copper PCB layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP7361-33D-13, the AP7361C-33D-13 adds EN control and ±1% accuracy essential for modern SoC interfaces; versus MCP1700-3302E/TO, it delivers 4× output current and integrated thermal cycling protection critical for sustained 1A operation.

Availability

AP7361C-33D-13 is available at Aetrix Electronics and suitable for LCD-TV mainboards, Set-Top-Box AV processing modules, and home appliance control panels requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AP7361C-33D-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, with design centers across Asia, Europe, and the US, and ISO/TS 16949-certified manufacturing facilities.

The AP7361C belongs to Diodes' high-performance LDO regulator product line, engineered for low-noise, high-accuracy power delivery in consumer electronics, set-top boxes, and industrial control systems where efficiency, reliability, and compact footprint are critical.

FAQ

What is the minimum input voltage required for AP7361C-33D-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; however, worst-case dropout may reach 440mV over temperature and process variation, so 4.0V input is recommended for margin. Below 3.66V, output voltage collapses nonlinearly.

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

No - the device requires a minimum 2.2µF ceramic output capacitor connected between OUT and GND for stability. Omitting it causes oscillation and unregulated output. The capacitor must be placed within 2mm of the OUT and GND pins using short, wide traces; tantalum or aluminum electrolytic types are not recommended due to ESR-related instability risks.

Is the EN pin functional in the TO252 (DPAK) package of AP7361C-33D-13?

Yes - unlike earlier AP7361 variants, the AP7361C series includes EN functionality across all packages including TO252 (D-suffix). Pin 4 is designated EN in the TO252 pinout per DS37274 Rev. 5-2, with VIH ≥ 1.0V and VIL ≤ 0.3V, and internal 3.0MΩ pull-down ensuring safe default-OFF behavior.

How does thermal shutdown behave under sustained overload conditions?

When junction temperature reaches +150°C, the output disables; it re-enables automatically once temperature falls to +130°C due to 20°C hysteresis. Under continuous overload (e.g., 1.2A into short), this causes thermal cycling - visible as periodic output toggling - which limits average power dissipation and prevents permanent damage, though system-level thermal design should avoid sustained cycling.