Diodes Incorporated AP1184K5-L-13

Overview

AP1184K5-L-13 from Diodes Incorporated is a 4A ultra-low dropout positive voltage regulator in TO263-5L package, configured for fixed 2.5V output (K5 = TO263-5L, blank = adjustable, but suffix "K5" with no voltage code implies adjustable mode per ordering table; however, J-column context and standard interpretation of AP1184K5-X-L-13 indicates K5 denotes package only, and absence of voltage code (e.g., 25) means ADJ mode - confirmed by datasheet section "Ordering Information": AP1184K5XXL-13 → XX = voltage code; here, "K5-L-13" has no explicit voltage suffix, thus ADJ mode). It delivers ≤0.85V dropout at 4A, features remote sensing (Vsense), thermal shutdown, and current limiting. Used in GPU core power delivery from 3.3V ATX rails.

For engineers reviewing the AP1184K5-L-13 datasheet, AP1184K5-L-13 pinout, AP1184K5-L-13 application, or AP1184K5-L-13 equivalent, key selection criteria include dropout voltage at full load, remote sense capability for load regulation, control pin (Vctrl) biasing requirements, and thermal resistance (θJA = 61°C/W) for surface-mount thermal design on FR-4 PCBs.

Technical Context

The AP1184 operates as an NPN-based LDO with externally biased control pin (Vctrl), enabling sub-1V dropout by decoupling base drive from Vin. Its five-terminal architecture separates Vout, Vsense, Adj (GND in fixed mode), Vctrl, and Vin to support true remote sensing and adjustable output via resistor divider.

It employs internal 1.25V reference with ±2.5% tolerance, achieves 60–70dB ripple rejection at 120Hz, and maintains load regulation within 1% (adjustable mode) or 25mV (2.5V fixed variant) across 0–4A. Thermal shutdown activates above 125°C junction temperature.

Key Specifications

Pinout & Package

AP1184K5-L-13 uses the TO263-5L surface-mount package (lead-free, RoHS-compliant), with exposed tab electrically connected to Vout for thermal conduction and low-inductance output path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable LDO applications.

Compared with LT1963AET-2.5#TRPBF and TPS7A8300RGRT, AP1184K5-L-13 uniquely supports 4A output with true remote sensing and external Vctrl biasing-enabling higher efficiency and tighter regulation in GPU/FPGA power delivery where auxiliary rails exist.

Availability

AP1184K5-L-13 is available at Aetrix Electronics and suitable for GPU core power supplies, industrial FPGA I/O banks, medical imaging sensor biasing, and test equipment precision references requiring stable component supply across extended production cycles.

Supply support for AP1184K5-L-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 AP1184 belongs to Diodes' high-current LDO family, engineered specifically for graphics processor and FPGA core power delivery from ATX-style 3.3V/5V rails where ultra-low dropout and remote sensing are mandatory.

FAQ

What is the correct configuration for the Adj pin on AP1184K5-L-13?

The AP1184K5-L-13 is an adjustable-mode regulator (no voltage suffix in part number), so the Adj pin serves as the reference node for the external R1/R2 divider. It must be connected to ground through R1 and to Vsense through R2. Per datasheet, R1 = 121Ω ensures minimum 10mA load current, and Vout = 1.25V × (1 + R2/R1) + (50µA × R2).

Can AP1184K5-L-13 operate without a dedicated Vctrl supply?

No. Vctrl must be ≥ Vin + 1V for regulation - e.g., with Vin = 3.3V, Vctrl ≥ 4.3V is mandatory. This pin powers the internal control circuitry and base drive; omitting it causes immediate dropout or failure to regulate. A separate 5V rail or LDO is required, and ≥100µF capacitor to ground is mandatory for stability.

How does remote sensing (Vsense) improve regulation accuracy?

Vsense connects directly to the load's power plane, allowing the regulator to measure voltage at the point-of-load rather than at its Vout pin. This compensates for voltage drop across PCB traces (e.g., 50mΩ × 4A = 200mV), maintaining ±1% regulation at the load despite layout-induced losses - critical for GPU/FPGA core rails.

Is AP1184K5-L-13 recommended for new designs?

No - the datasheet explicitly states "NOT RECOMMENDED FOR NEW DESIGN" (Rev. 6-3, Oct 2014). While fully functional and supported, Diodes recommends newer alternatives like the AP7361 series for new projects. Aetrix Electronics continues to stock AP1184K5-L-13 for legacy system repair, long-lifecycle industrial maintenance, and drop-in replacement in existing designs.