Diodes Incorporated AP1184K5-15L-U

Overview

AP1184K5-15L-U from Diodes Incorporated is a 4A ultra-low dropout positive voltage regulator in TO263-5L package, configured for fixed 1.5V output. It delivers 1.500V ±30mV at 10mA load with 0.85V max dropout at 4A, built-in thermal shutdown and current limiting, and supports remote sensing via Vsense pin for precision load regulation - used in GPU core power supplies requiring stable 2.4–2.7V derived from 3.3V ATX rails.

For engineers reviewing the AP1184K5-15L-U datasheet, AP1184K5-15L-U pinout, AP1184K5-15L-U application, or AP1184K5-15L-U equivalent, key selection criteria include dropout voltage under 4A load, remote sense capability for <15mV load regulation, thermal resistance (θJA = 61°C/W), control pin (Vctrl) biasing requirements, and compatibility with aluminum electrolytic output capacitors ≥100µF.

Technical Context

The AP1184K5-15L-U implements an NPN-based LDO architecture with externally biased Vctrl pin, enabling sub-1V dropout by decoupling base drive from Vin. Its five-terminal design separates Vout, Vsense, and Vctrl to support true remote sensing and independent control rail optimization.

It operates with fixed 1.5V output (no external resistor divider needed), requires ≥100µF output capacitance for stability, and mandates ≥100µF on Vctrl and ≥10µF on Vsense for transient response integrity. Thermal shutdown activates above 125°C junction temperature.

Key Specifications

Pinout & Package

AP1184K5-15L-U uses the TO263-5L surface-mount package with exposed thermal pad (Vout-connected tab). Pin numbering follows front-view orientation; Tab is electrically connected to Vout for enhanced thermal conduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1184K5-15L-U, AP1186K5-15L-U offers higher current headroom and better thermal performance in identical TO263-5L footprint, while TPS7A8300RGRT trades remote sensing capability for digital control and lower dropout - making AP1184K5-15L-U optimal for cost-sensitive, high-accuracy analog load-point regulation.

Availability

AP1184K5-15L-U is available at Aetrix Electronics and suitable for GPU core power supplies, ATX motherboard auxiliary rails, industrial FPGA I/O banks, and embedded vision sensor bias circuits requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for AP1184K5-15L-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 power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The AP1184 series belongs to Diodes' high-current LDO portfolio, designed specifically for low-voltage, high-transient GPU and FPGA core regulation where efficiency, accuracy, and thermal robustness outweigh switching complexity.

FAQ

What is the minimum required output capacitance for stable operation?

The AP1184K5-15L-U requires a minimum of 100µF aluminum electrolytic capacitor on the Vout pin to ensure loop stability and adequate transient response. This value assumes typical ESR of 50–100mΩ; lower-ESR ceramics may destabilize the regulator unless combined with appropriate series resistance or parallel electrolytic.

Can the Vsense pin be left unconnected in fixed-output mode?

No - the Vsense pin must be connected directly to the load point (or to Vout if remote sensing is not needed), and bypassed with ≥10µF capacitor to ground. Leaving it floating causes regulation instability and potential overvoltage at the load due to uncontrolled feedback path impedance.

Why does Vctrl require a higher voltage than Vin?

Vctrl supplies the base drive for the internal NPN pass transistor and powers the control circuitry. It must exceed Vout by ≥1V to maintain sufficient Vce saturation margin and ensure full conduction at 4A. Using Vin as Vctrl would collapse dropout performance and risk thermal runaway under heavy load.

Is AP1184K5-15L-U recommended for new designs?

No - Diodes Incorporated marks AP1184 as "NOT RECOMMENDED FOR NEW DESIGN" in its official documentation (Rev. 6-3, October 2014). It remains available for legacy support and existing production, but designers should evaluate newer alternatives like AP1186 or industry-standard replacements for long-term viability.