Diodes Incorporated AP1186K5-L-U

Overview

AP1186K5-L-U from Diodes Incorporated is a 1.5A ultra-low dropout positive voltage regulator in TO263-5L package, configurable as adjustable or fixed-output (1.5V/1.8V/2.5V/3.3V/5.0V), with 0.26V typical dropout at 1.5A, remote sensing capability via Vsense pin, and integrated thermal shutdown - deployed in graphics chipset power rails requiring 2.4–2.7V from 3.3V ATX supplies.

For engineers reviewing the AP1186K5-L-U datasheet, AP1186K5-L-U pinout, AP1186K5-L-U application, or AP1186K5-L-U equivalent, key selection criteria include dropout voltage under full load, remote sensing accuracy, control pin (Vctrl) biasing requirements, thermal resistance (ΘJC = 2.5°C/W), and compatibility with aluminum electrolytic output capacitors ≥100µF.

Technical Context

The AP1186 employs an NPN pass transistor architecture with externally biased Vctrl pin-enabling lower dropout than PNP regulators without base current losses. Its five-terminal topology separates Vout and Vsense to support true remote load sensing, compensating for PCB trace IR drop.

It delivers fast transient response (300–500ns current step handling) and 60–70dB ripple rejection at 120Hz, optimized for microprocessor and GPU core supply where tight initial tolerance (±1% for fixed versions) and dynamic regulation are critical. The device operates with junction temperatures up to +150°C and includes current limiting and thermal shutdown.

Key Specifications

Pinout & Package

AP1186K5-L-U uses the TO263-5L surface-mount package with exposed tab electrically connected to Vout for low-inductance thermal path and power return. Pin 1 is Vout (tab), Pin 2 is Vsense, Pin 3 is Adj (GND in fixed mode), Pin 4 is Vctrl, Pin 5 is Vin.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with AP1186T5-L-U, the K5 variant offers superior thermal performance in SMT layouts; versus TPS7A4700RGWR, it trades noise floor for higher current, remote sensing, and flexible biasing-making it uniquely suited for ATX-derived GPU and chipset rails.

Availability

AP1186K5-L-U is available at Aetrix Electronics and suitable for graphics card power delivery, ATX motherboard auxiliary rails, industrial FPGA I/O regulation, and medical imaging sensor bias requiring stable component supply with RoHS-compliant lead-free finish.

Supply support for AP1186K5-L-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 semiconductor manufacturer specializing in discrete, analog, and mixed-signal devices, with emphasis on power management, signal integrity, and protection solutions.

The AP1186 belongs to Diodes' high-current LDO regulator product line, engineered specifically for graphics and computing applications needing ultra-low dropout, remote sensing, and dual-input biasing from ATX-style power supplies.

FAQ

What is the function of the Vctrl pin on AP1186K5-L-U?

The Vctrl pin supplies bias voltage to the internal control circuitry and NPN pass transistor base drive. It must be ≥1V above Vout to maintain regulation. In ATX systems, it is commonly connected to the 5V rail while Vin is sourced from 3.3V, enabling ultra-low dropout operation without sacrificing control loop stability.

Can AP1186K5-L-U be used in adjustable-output mode?

Yes - the AP1186K5-L-U is the fixed-output variant (2.5V), but the underlying AP1186-ADJ die supports adjustable mode via external R1/R2 resistors between Adj, Vsense, and Vout. To use adjustable mode, select the AP1186K5-ADJ variant (if offered) or confirm pin-compatible adjustable marking on the device body per Diodes' marking guide.

What output capacitor is required for stability?

A minimum 100µF aluminum electrolytic capacitor with ESR between 50–100mΩ is required at the Vout pin. This value satisfies both stability and transient response requirements for GPU and FPGA loads. The Vsense pin additionally requires ≥10µF to ground for loop stability.

How does remote sensing work on AP1186K5-L-U?

Remote sensing uses the dedicated Vsense pin to monitor voltage directly at the load (e.g., GPU BGA). The regulator adjusts Vout to maintain 1.25V between Vsense and Adj, compensating for voltage drop across PCB traces. This ensures ±10mV regulation accuracy at the load, even with 50mΩ trace resistance.