Diodes Incorporated AP1084K18G-13

Overview

AP1084K18G-13 from Diodes Incorporated is a 5A low-dropout positive fixed-mode voltage regulator delivering a precise 1.8V output with ≤1.4V dropout at full load, thermal shutdown protection, and built-in current limiting. It uses the TO263-3L package with exposed thermal tab connected to VOUT, and is designed for high-speed bus termination and low-current 3.3V logic supply in VGA cards and embedded power rails.

For engineers reviewing the AP1084K18G-13 datasheet, AP1084K18G-13 pinout, AP1084K18G-13 application, or AP1084K18G-13 equivalent, key selection criteria include guaranteed 1.4V max dropout at 5A, ±1.5% output voltage tolerance at 10mA, 100µF minimum output capacitance requirement, and thermal resistance of 60°C/W (junction-to-case) for reliable thermal management in compact PCB layouts.

Technical Context

The AP1084K18G-13 integrates a precision 1.25V bandgap reference, error amplifier, and PNP pass transistor in a fixed-output configuration. Its internal current limit is set at 5.1A under 5V VIN–VOUT differential, and thermal shutdown activates at 150°C junction temperature.

It operates across 0°C to 125°C junction temperature range with input voltage support from 3.3V to 12V, enabling stable 1.8V regulation from 4.7V–12V supplies. Load regulation is specified at 15–18mV over 0–5A output current at TA = 25°C, and line regulation is 0.2% for VIN variations within operating range.

Key Specifications

Pinout & Package

AP1084K18G-13 uses the TO263-3L (D²PAK) surface-mount package with an exposed thermal pad electrically connected to the VOUT terminal. The package supports high-power dissipation with low thermal resistance and is RoHS-compliant and green compound (halogen-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1084K18G-13, AP1084K18L-13 offers identical performance with non-green packaging, while TLV1117-18CDR trades 5A capability and thermal robustness for small footprint-making it unsuitable for high-power 1.8V rails.

Availability

AP1084K18G-13 is available at Aetrix Electronics and suitable for VGA graphics cards, FPGA power delivery, industrial PLC I/O modules, and embedded camera sensor interfaces requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for AP1084K18G-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 product line delivers high-current, low-dropout regulation for demanding digital power rails-including bus termination, FPGA cores, and GPU memory-where thermal efficiency and transient response are critical.

FAQ

What is the minimum input voltage required for AP1084K18G-13 to regulate at 1.8V?

The device requires VIN ≥ VOUT + 1.4V to maintain regulation, so minimum input is 3.2V. At lower differentials, output voltage drops linearly with input; operation below 3.2V results in unregulated dropout behavior. Input must also stay within absolute maximum rating of 12V.

Can AP1084K18G-13 be used in adjustable mode?

No-AP1084K18G-13 is factory-configured as a fixed 1.8V output device. The "K18" suffix denotes fixed 1.8V version in TO263-3L package. Adjustable versions use blank suffix (e.g., AP1084K-13) and require external R1/R2 resistors to set VOUT between 1.25V and VIN–1.4V.

Is a heatsink mandatory for 5A continuous operation?

Yes-thermal resistance θJA is 60°C/W on recommended FR-4 layout. At 5A with 3.2V input (1.4V dropout), power dissipation is 7W. Without heatsinking, junction temperature would exceed 150°C even at 25°C ambient. A heatsink or large copper pour is essential for sustained 5A loads.

What output capacitor ESR range ensures stability?

The datasheet specifies 0.15Ω to 20Ω ESR for the minimum 10µF output capacitor. Aluminum electrolytic, tantalum, or polymer capacitors within this range guarantee phase margin and prevent oscillation. Ceramic capacitors alone (ESR < 0.01Ω) may cause instability unless paralleled with a resistor or higher-ESR capacitor.