Diodes Incorporated AP1186K5-15L-U

Overview

AP1186K5-15L-U from Diodes Incorporated is a 1.5A ultra-low dropout positive fixed-mode linear regulator with 1.5V output, TO263-5L package, 0.38V max dropout at 1.5A, and integrated thermal shutdown and current limiting. It delivers stable 1.5V supply for graphics chipset core rails powered from 3.3V ATX sources.

For engineers reviewing the AP1186K5-15L-U datasheet, AP1186K5-15L-U pinout, AP1186K5-15L-U application, or AP1186K5-15L-U equivalent, key selection criteria include dropout voltage under full load, remote sensing capability via Vsense pin, thermal resistance (ΘJC = 2.5°C/W), and stability with ≥100µF aluminum electrolytic output capacitance.

Technical Context

The AP1186K5-15L-U uses an NPN pass transistor architecture with externally supplied Vctrl pin-separate from Vin-to eliminate base-current-related power loss and achieve sub-0.4V dropout. Its five-terminal design enables true remote voltage sensing by decoupling Vsense from Vout, compensating for PCB trace IR drop.

It operates in fixed-output mode (1.5V) with internal reference trimmed to ±2% over temperature and load. The control loop is optimized for fast transient response (300–500ns current steps), supporting GPU core rail requirements where initial accuracy and dynamic regulation are both critical.

Key Specifications

Pinout & Package

AP1186K5-15L-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.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1186T5-15L-U, the K5 variant offers superior thermal interface via surface-mount tab; versus TPS7A4700RGWR, it trades noise floor for essential remote sensing and ATX-compatible dual-input flexibility-critical for graphics and embedded motherboard designs.

Availability

AP1186K5-15L-U is available at Aetrix Electronics and suitable for graphics processor core supplies, ATX-based embedded system rails, low-noise analog subsystem bias, and legacy PCI Express slot auxiliary rails requiring stable component supply and long-term manufacturability.

Supply support for AP1186K5-15L-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 high-reliability power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The AP1186 product line targets high-current, ultra-low-dropout regulation in space-constrained computing platforms-specifically designed to replace inefficient PNP-based regulators while maintaining compatibility with existing ATX power architectures.

FAQ

What is the minimum input voltage required for AP1186K5-15L-U to regulate at 1.5V with 1.5A load?

The absolute minimum input voltage is 1.88V (1.5V + 0.38V dropout), but Diodes specifies 2.05V as the test condition for 1.5A dropout. For reliable operation across temperature and process variation, maintain Vin ≥ 2.2V. Input must also satisfy Vctrl ≥ Vin + 1V, so with Vctrl = 5V, Vin must stay ≤ 4V to avoid violating that constraint.

Can AP1186K5-15L-U be used without connecting the Vsense pin?

Yes-Vsense may be tied directly to Vout for local regulation, but doing so forfeits remote sensing benefits. When shorted, load regulation degrades from 15mV to ~25mV due to uncompensated PCB trace resistance. The device remains fully functional and stable, as confirmed in the datasheet's "Local Sensing" configuration on page 6.

Is an external resistor divider required to set the 1.5V output?

No. The "-15" suffix denotes factory-trimmed fixed 1.5V output; the Adj pin is internally connected to GND. No external resistors are needed-unlike the adjustable AP1186-ADJ variant. This simplifies layout and eliminates resistor tolerance errors affecting output accuracy.

What is the recommended PCB copper area for thermal management of AP1186K5-15L-U at 1.5A continuous load?

Diodes recommends a minimum 1.4" × 1.4" (35.6mm × 35.6mm) copper pad connected to the exposed Vout tab. With this area, ΘJA drops to 25–45°C/W, enabling up to 2.4W dissipation at 25°C ambient-well above the 1.68W calculated for 3.3V→1.5V conversion at 1.5A.