Diodes Incorporated AP1184K5-18L-13

Overview

AP1184K5-18L-13 from Diodes Incorporated is a 4A ultra-low dropout positive fixed-mode linear regulator in TO263-5L package, delivering 1.8V output with ≤0.85V dropout at full load, built-in thermal shutdown and current limiting, and optimized for GPU core supply from 3.3V ATX rails in graphics card designs.

For engineers reviewing the AP1184K5-18L-13 datasheet, AP1184K5-18L-13 pinout, AP1184K5-18L-13 application, or AP1184K5-18L-13 equivalent, key selection criteria include dropout voltage under 4A load, remote sensing capability via Vsense pin, Vctrl biasing requirements, thermal resistance (θJC = 7°C/W), and fixed-output stability with ≥100µF output capacitance.

Technical Context

The AP1184K5-18L-13 uses a five-terminal NPN-based architecture with separate Vctrl and Vsense pins to decouple control biasing from input power and enable true remote voltage sensing at the load. Its adjustable reference (1.25V ±2.5%) and low I_adj (50–150 µA) support precise fixed-output derivation without external resistors in 1.8V configuration.

It achieves fast transient response (<500 ns load step recovery) through internal compensation tuned for aluminum electrolytic output capacitors (100–1000 µF, ESR 50–100 mΩ), while thermal shutdown activates above 125°C junction temperature and current limit triggers at 4.2A typical.

Key Specifications

Pinout & Package

AP1184K5-18L-13 is housed in a surface-mount TO263-5L (D²PAK) package with exposed tab electrically connected to Vout for thermal and electrical integration. The tab must be soldered to a large copper pour for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1184K5-18L-13, AP1186K5-18L-13 offers higher current headroom in identical packaging, while TPS7A8300RGRT trades current capacity for compactness and lower quiescent current-neither matches the 4 A/0.85 V dropout combination in TO263-5L.

Availability

AP1184K5-18L-13 is available at Aetrix Electronics and suitable for graphics card GPU core supply, ATX motherboard secondary rail generation, industrial FPGA I/O bank regulation, and test equipment digital logic supply requiring stable component supply with long-term lifecycle support.

Supply support for AP1184K5-18L-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-performance power management, signal integrity, and protection solutions for computing, industrial, and consumer markets.

The AP1184 product line delivers ultra-low-dropout linear regulators targeting high-current, low-voltage applications such as GPU and FPGA core supplies where switching noise must be avoided and efficiency from intermediate rails is critical.

FAQ

Is AP1184K5-18L-13 pin-compatible with other AP1184 fixed-output variants?

Yes - all AP1184 fixed-output versions (e.g., -15, -18, -25, -33, -50) in TO263-5L (K5) or TO220-5L (T5) packages share identical pin assignments and thermal design requirements. Only the output voltage and associated internal resistor network differ; no layout change is needed when switching between 1.5 V, 1.8 V, or 2.5 V variants.

What is the minimum required capacitor on the Vctrl pin, and why is it critical?

A minimum 100 µF aluminum electrolytic capacitor is required from Vctrl to ground. This capacitor stabilizes the internal control circuit's bias supply during fast load transients; insufficient capacitance causes oscillation or thermal shutdown due to Vctrl droop below Vout +1 V, especially under 4 A load steps.

Can AP1184K5-18L-13 operate without remote sensing (Vsense unconnected)?

No - Vsense must be connected directly to Vout (or to the load) and bypassed with ≥10 µF to ground. Leaving Vsense floating violates the internal error amplifier topology and causes output voltage instability or failure to regulate. In fixed-mode variants, Vsense is internally referenced to Vout but still requires external connection for proper loop closure.

Why does Diodes Incorporated mark AP1184 as "NOT RECOMMENDED FOR NEW DESIGN"?

This marking reflects Diodes' internal product lifecycle policy: AP1184 remains fully manufactured and supported, but newer alternatives (e.g., AP1186 series) offer higher current ratings and improved thermal performance. It does not indicate obsolescence, reliability issues, or discontinuation - Aetrix Electronics maintains active inventory and long-term supply assurance for AP1184K5-18L-13.