Diodes Incorporated AP1084D18G-13

Overview

AP1084D18G-13 from Diodes Incorporated is a 5A low-dropout linear regulator in fixed 1.8V output mode, housed in a TO252-3L surface-mount package. It delivers stable 1.8V at up to 5A with ≤1.4V dropout at full load, built-in thermal shutdown and current limiting, and supports fast transient response for high-speed bus termination and low-current 3.3V logic supply applications.

For engineers reviewing the AP1084D18G-13 datasheet, AP1084D18G-13 pinout, AP1084D18G-13 application, or AP1084D18G-13 equivalent, this device is selected for high-current, low-noise local regulation where input-to-output differential is constrained (e.g., 4.7–12V input → 1.8V output), stability under dynamic load steps matters, and RoHS-compliant green packaging is required.

Technical Context

The AP1084D18G-13 operates as a three-terminal adjustable/fixed LDO with internal 1.25V reference and precision error amplifier. Its dropout voltage remains ≤1.4V at 5A, enabling regulation from inputs as low as 3.2V while maintaining 1.8V output. The device uses external resistor feedback only in adjustable mode; in fixed 1.8V mode, the ADJ pin functions as ground.

Thermal protection activates at 150°C junction temperature, and output stability requires ≥10µF capacitor (ESR 0.15–20Ω). Load regulation is specified at ±15–18mV over 0–5A at 25°C, and line regulation is ≤0.2% across VIN range.

Key Specifications

Pinout & Package

AP1084D18G-13 uses the TO252-3L (DPAK) thermally enhanced surface-mount package. The exposed thermal pad (Tab) is electrically connected to VOUT and must be soldered to a large PCB copper pour for thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1084K18G-13, the D2PAK offers superior thermal dissipation but increases PCB area; compared with TLV1117-18CDCYR, AP1084D18G-13 provides 6.25× higher current and maintains regulation at lower input voltages, making it irreplaceable in 5A 1.8V system rails.

Availability

AP1084D18G-13 is available at Aetrix Electronics and suitable for DDR memory termination, VGA graphics card power, and industrial FPGA I/O banks requiring stable component supply with RoHS-compliant green packaging and surface-mount assembly compatibility.

Supply support for AP1084D18G-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 manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The AP1084 series belongs to Diodes' high-current LDO portfolio, designed specifically for low-voltage, high-current IC supply rails-including bus termination, logic core power, and graphics subsystems-where dropout, transient response, and thermal robustness are critical.

FAQ

What is the minimum input voltage required for AP1084D18G-13 to regulate at 1.8V?

The minimum input voltage is determined by dropout: VIN ≥ VOUT + VDROP = 1.8V + 1.4V = 3.2V. However, the datasheet specifies operation starting at 3.3V for 1.8V output to ensure margin across temperature and load. Below 3.3V, regulation is not guaranteed, and output will track VIN minus dropout.

Can AP1084D18G-13 be used in adjustable mode?

No. AP1084D18G-13 is factory-configured for fixed 1.8V output. The "D" prefix indicates TO252-3L package, and "18" denotes fixed 1.8V; the ADJ pin is internally grounded. To use adjustable mode, select AP1084D-13 (no voltage suffix) and add external R1/R2 resistors per the VOUT = 1.25V × (1 + R2/R1) formula.

Is an input capacitor required for stable operation?

Yes. Although not part of the internal compensation network, a minimum 10µF aluminum or tantalum capacitor (with ESR 0.15–20Ω) is required at VIN to prevent input sag during load transients and suppress upstream noise. Without it, the regulator may experience instability or fail to maintain regulation under dynamic loads.

How should the thermal tab (VOUT) be connected on the PCB?

The exposed thermal pad (Tab) is electrically connected to VOUT and must be soldered to a dedicated, low-thermal-resistance copper pour on the PCB. Use ≥4 thermal vias (0.3mm diameter, filled or capped) connecting the pad to inner-layer or back-side ground/power planes. Do not float or isolate the tab-it is essential for both thermal performance and electrical integrity.