Diodes Incorporated AP7361C-33ER-13

Overview

AP7361C-33ER-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 portable and battery-powered 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). It powers core logic rails in LCD-TV mainboards.

For engineers reviewing the AP7361C-33ER-13 datasheet, AP7361C-33ER-13 pinout, AP7361C-33ER-13 application, or AP7361C-33ER-13 equivalent, key selection criteria include dropout performance at 1A load, EN pin logic thresholds (VIH = 1.0V, VIL = 0.3V), stability with ≥2.2µF MLCC output capacitors, and thermal resistance (θJA = 110°C/W) in SOT223R package.

Technical Context

The AP7361C-33ER-13 uses a PMOS pass transistor architecture enabling ultra-low dropout voltage and high PSRR (75dB @ 1kHz). 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 control is implemented as a logic-level input (EN pin) with internal 3.0MΩ pull-down resistor and ±0.1µA leakage. Protection circuitry includes fold-back current limiting triggered at ~400mA during short-circuit events and thermal shutdown activation at 150°C with 20°C hysteresis.

Key Specifications

Pinout & Package

SOT223R package: thermally enhanced 3-pin variant with reversed pinout (Pin 1 = GND, Pin 2 = OUT, Pin 3 = IN) and exposed thermal pad for improved heat dissipation in compact layouts.

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 TPS7A2033PDBVR, AP7361C-33ER-13 uniquely combines 1A output, 360mV dropout, and enable functionality in a thermally robust SOT223R package - making it the only viable option for space-constrained, medium-power 3.3V rail generation where thermal management and load switching are critical.

Availability

AP7361C-33ER-13 is available at Aetrix Electronics and suitable for LCD-TV mainboards, set-top box power management, and home appliance control boards requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AP7361C-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 company specializing in discrete, analog, and mixed-signal ICs for power management, signal integrity, and connectivity applications.

The AP7361C belongs to Diodes' high-performance LDO regulator product line, engineered for battery-powered and space-constrained consumer electronics demanding ultra-low dropout, low IQ, and robust protection features.

FAQ

What is the minimum input voltage required for AP7361C-33ER-13 to maintain regulation at full 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 dropout (per datasheet) is 340mV for 3.3V output. Therefore, 3.64V input guarantees regulation under all conditions within spec limits.

Can AP7361C-33ER-13 be used without connecting the EN pin?

Yes - the EN pin has an internal 3.0MΩ pull-down resistor. Leaving it unconnected defaults the device to enabled state. However, for guaranteed startup in noisy environments, tie EN directly to IN. Do not float EN in high-EMI applications where coupling could cause unintended shutdown.

Is the SOT223R package electrically identical to standard SOT223 for AP7361C-33ER-13?

No - SOT223R reverses the pinout: Pin 1 = GND, Pin 2 = OUT, Pin 3 = IN (vs. standard SOT223: Pin 1 = IN, Pin 2 = GND, Pin 3 = OUT). The thermal pad connection and electrical specs are identical, but PCB layout must reflect the reversed pin assignment to avoid functional failure.

Does AP7361C-33ER-13 require a minimum load current to maintain regulation stability?

No - the device remains stable and regulated down to zero load current. The datasheet explicitly states "no minimum load is required" and confirms stability in no-load condition, eliminating need for dummy loads in standby or low-power modes.