Diodes Incorporated AP7361C-18SPR-13

Overview

AP7361C-18SPR-13 from Diodes Incorporated is a 1A fixed-output (1.8V) ultra-low dropout linear regulator with enable, designed for power rail regulation in space-constrained applications. It delivers ±1% output voltage accuracy, 360mV dropout at 1A (for 3.3V variant; 1.8V dropout is 440mV typ), 60µA quiescent current, and integrates current limit (1.5A), thermal shutdown (150°C), and fold-back short-circuit protection (400mA). It is used in LCD-TV power supplies and set-top-box core logic rails.

For engineers reviewing the AP7361C-18SPR-13 datasheet, AP7361C-18SPR-13 pinout, AP7361C-18SPR-13 application, or AP7361C-18SPR-13 equivalent, key selection criteria include dropout performance at 1.8V output, SO-8EPR package thermal resistance (100°C/W), EN pin logic thresholds (VIH = 1.0V min), stability with ≥2.2µF MLCC output capacitors, and compatibility with low-noise portable and consumer electronics power domains.

Technical Context

The AP7361C-18SPR-13 implements a PMOS pass transistor architecture enabling ultra-low dropout and high PSRR (75dB @ 1kHz). Its internal 0.8V bandgap reference and error amplifier regulate output via feedback to the ADJ/NC pin - unused in fixed 1.8V configuration but retained for pin compatibility across variants.

Enable control is implemented as active-high logic with 1.0V minimum VIH and 0.3V maximum VIL; internal 3.0MΩ EN pull-down ensures default-off behavior if left floating. Protection circuitry includes fold-back current limiting that reduces short-circuit current to 400mA and thermal shutdown with 20°C hysteresis.

Key Specifications

Pinout & Package

AP7361C-18SPR-13 is packaged in SO-8EPR: thermally enhanced 8-pin small-outline package with exposed pad, optimized for surface-mount assembly and improved heat dissipation (θJA = 100°C/W on FR-4).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700-1802E/TO, AP7361C-18SPR-13 offers 3.3× higher current capacity and integrated enable/thermal protection; versus XC6210B182MR-G, it trades 190mV higher dropout for SO-8EPR's superior thermal performance and drop-in compatibility with existing 8-pin layouts.

Availability

AP7361C-18SPR-13 is available at Aetrix Electronics and suitable for LCD-TV power management, set-top-box core logic, and smart home hub MCU applications requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.

Supply support for AP7361C-18SPR-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 AP7361C belongs to Diodes' high-performance LDO regulator product line, engineered for low-noise, low-dropout power delivery in consumer, computing, and industrial systems where reliability and compact packaging are critical.

FAQ

What is the recommended input and output capacitor configuration for AP7361C-18SPR-13?

A 1µF ceramic capacitor is required between IN and GND; a minimum 2.2µF ceramic capacitor must be placed between OUT and GND. Both capacitors must be located adjacent to their respective pins using short, wide traces. Higher capacitance improves load transient response, and low-ESR MLCCs are strongly preferred over electrolytic types.

Does AP7361C-18SPR-13 require a minimum load current to maintain regulation?

No. The AP7361C-18SPR-13 remains stable and fully regulated under no-load conditions. Unlike some older LDOs, it does not require a minimum output current to sustain regulation or avoid oscillation, simplifying design for intermittent-load applications like sensor hubs or wake-on-event circuits.

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

The EN pin must not be left floating. Due to its internal 3.0MΩ pull-down resistor, leaving it unconnected results in guaranteed disable state. For always-on operation, tie EN directly to IN. For controlled enable/disable, drive it with a logic signal meeting VIH ≥ 1.0V and VIL ≤ 0.3V specifications.

How does thermal performance differ between SO-8EPR and other AP7361C packages?

SO-8EPR (AP7361C-18SPR-13) has θJA = 100°C/W, significantly better than SOT89-5 (150°C/W) and comparable to TO252 (95°C/W). Its exposed pad and dual GND pins enable efficient heat transfer to PCB copper, allowing 1A operation at higher ambient temperatures without derating when properly laid out with thermal vias.