Diodes Incorporated AP1184K5-25L-U

Overview

AP1184K5-25L-U from Diodes Incorporated is a 4A ultra-low dropout positive voltage regulator in TO263-5L package, configured for fixed 2.5V output. It delivers 2.5V/4A with 0.85V max dropout at full load, built-in thermal shutdown and current limiting, and supports remote sensing via Vsense pin for precise load regulation - deployed in GPU power rails requiring stable 2.4–2.7V supply from 3.3V ATX sources.

For engineers reviewing the AP1184K5-25L-U datasheet, AP1184K5-25L-U pinout, AP1184K5-25L-U application, or AP1184K5-25L-U equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative parts with documented differences, and supply support for industrial embedded and graphics subsystem designs.

Technical Context

The AP1184K5-25L-U uses a five-terminal NPN-based architecture with separate Vctrl and Vsense pins to decouple control biasing from input voltage, enabling sub-1V dropout while avoiding base-current losses typical of PNP regulators. Its adjustable/fixed mode is determined by internal resistor network - this variant is factory-set to 2.5V (K5-25 suffix).

Remote sensing is implemented through dedicated Vsense pin tied to load point, compensating for PCB trace IR drop; stability relies on ≥100µF output capacitor with 50–100mΩ ESR. Thermal shutdown activates above 150°C junction temperature, and current limit is fixed at 4.2A minimum.

Key Specifications

Pinout & Package

AP1184K5-25L-U is housed in a surface-mount TO263-5L (D²PAK) package with exposed tab electrically connected to Vout for thermal conduction and low-inductance output path. The tab must be soldered to ≥1.4"×1.4" 2oz copper pad per AP02001 layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1184T5-25L-U, the K5 variant offers superior thermal performance in dense SMT layouts; versus TPS7A8300RGRT, it delivers 33% higher current and true remote sensing essential for motherboard-level accuracy - making it irreplaceable in ATX GPU power delivery.

Availability

AP1184K5-25L-U is available at Aetrix Electronics and suitable for GPU power delivery, ATX motherboard auxiliary rails, FPGA I/O regulation, and precision test equipment reference supplies requiring stable component supply and long-lifecycle support.

Supply support for AP1184K5-25L-U 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 AP1184 product line targets high-current, ultra-low-dropout linear regulation in computing infrastructure - specifically engineered to replace switching regulators in GPU and chipset power rails where noise, cost, and layout complexity must be minimized.

FAQ

Is AP1184K5-25L-U recommended for new designs?

No - Diodes Incorporated marks AP1184 as "NOT RECOMMENDED FOR NEW DESIGN" in its official datasheet (Rev. 6-3, Oct 2014). This reflects obsolescence planning due to newer architectures; however, it remains actively stocked and supported for legacy system repair, second-source needs, and cost-sensitive industrial upgrades where qualification cycles prohibit redesign.

What is the minimum required capacitor on the Vctrl pin?

A minimum 100µF aluminum electrolytic capacitor is required between Vctrl and ground to ensure loop stability and prevent oscillation during large load transients. This value is specified in the Absolute Maximum Ratings section and validated in the Stability application note - smaller values risk instability under 4A step loads.

Can AP1184K5-25L-U operate without connecting the Vsense pin?

Yes, but with degraded performance: leaving Vsense unconnected or tying it directly to Vout disables remote sensing, reverting to local regulation with up to 50mV additional error from PCB trace resistance. For GPU applications where load regulation must stay within ±1%, Vsense must be routed to the load point.

What thermal derating applies at 70°C ambient?

At TA = 70°C, maximum continuous output current drops to ~2.8A for TO263-5L (based on θJA = 61°C/W and TJ(max) = 150°C). Derating follows Pd = (TJ − TA)/θJA; with 2.5V output and 3.3V input, power dissipation exceeds safe limits above this current unless additional copper area or forced airflow is applied.