Diodes Incorporated AP1186K5-33G-13

Overview

AP1186K5-33G-13 from Diodes Incorporated is a 1.5A ultra-low dropout positive fixed-mode linear regulator in TO263-5L package, delivering a stable 3.3V output with ≤0.38V dropout at 1.5A load and built-in thermal shutdown and current limiting. It supports remote sensing via separate Vsense pin for precise load regulation and is optimized for GPU core supply in ATX-based motherboards requiring tight transient response and low-noise 3.3V rails.

For engineers reviewing the AP1186K5-33G-13 datasheet, AP1186K5-33G-13 pinout, AP1186K5-33G-13 application, or AP1186K5-33G-13 equivalent, key selection criteria include dropout voltage under full load, remote sensing capability, thermal resistance (ΘJC = 2.5°C/W), control pin (Vctrl) biasing requirements, and compatibility with high-ESR electrolytic output capacitors.

Technical Context

The AP1186K5-33G-13 uses an NPN pass transistor architecture with externally biased Vctrl pin-requiring Vctrl > Vin-to eliminate base-current losses typical of PNP LDOs. Its five-terminal topology separates Vout and Vsense to enable true remote voltage sensing at the load point, compensating for PCB trace IR drop.

It achieves fast transient response through internal compensation tuned for ≥100µF aluminum electrolytic output capacitors (50–100mΩ ESR), and integrates thermal shutdown triggered above 150°C junction temperature plus foldback current limiting at 1.6A nominal.

Key Specifications

Pinout & Package

AP1186K5-33G-13 is housed in a surface-mount TO263-5L (D²PAK) package with exposed tab electrically connected to Vout for thermal conduction. The tab must be soldered to a ≥1.4″×1.4″ copper pour for thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1186T5-33G-13 and TPS7A4700RGWR, the AP1186K5-33G-13 uniquely combines 1.5A current, remote sensing, and ultra-low dropout in a thermally efficient SMT package-making it irreplaceable for ATX-based GPU power where both precision and power delivery coexist.

Availability

AP1186K5-33G-13 is available at Aetrix Electronics and suitable for GPU core power supply, ATX motherboard secondary rail generation, and industrial FPGA I/O bank regulation requiring stable component supply, consistent parametric performance, and RoHS-compliant packaging.

Supply support for AP1186K5-33G-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 devices for computing, industrial, and consumer markets.

The AP1186 series belongs to Diodes' ultra-low dropout linear regulator product line, engineered specifically for high-current, low-voltage GPU and chipset power delivery in ATX platforms where switching complexity must be avoided.

FAQ

What is the minimum required capacitor on the Vctrl pin?

A minimum 100µF aluminum electrolytic capacitor must be placed between Vctrl and ground to ensure stability of the internal control circuitry and prevent oscillation during load transients. This capacitor also filters noise coupling from the bias rail into the pass transistor gate drive path.

Can AP1186K5-33G-13 operate without remote sensing?

Yes - the Vsense pin may be shorted directly to Vout for local regulation, but doing so forfeits the primary advantage of the device: compensation for PCB trace voltage drop. Load regulation degrades from ≤33mV to ~1% without remote sensing, especially under high-current dynamic loads.

Is the exposed tab electrically isolated?

No - the exposed tab in the TO263-5L package is internally connected to the Vout pin and must be soldered to a grounded or 3.3V copper plane accordingly. Isolation would compromise thermal performance and violate the device's ΘJC specification of 2.5°C/W.

Why does Vctrl need to be higher than Vin?

Vctrl supplies base drive to the NPN pass transistor; setting Vctrl > Vin ensures sufficient V_BE headroom to maintain saturation and minimize dropout. At Vctrl = Vin, the transistor enters linear region, increasing dropout and thermal stress - hence the 1V minimum overhead requirement.