Diodes Incorporated AP1186T5-L-U

Overview

AP1186T5-L-U from Diodes Incorporated is a 1.5A ultra-low dropout positive voltage regulator in TO220-5L package, supporting fixed output voltages (1.5V/1.8V/2.5V/3.3V/5.0V) or adjustable mode via external resistors. It delivers ≤0.38V dropout at 1.5A load, features remote sensing (Vsense pin), thermal shutdown, and current limiting. It is used to power graphics chipsets requiring 2.4–2.7V from 3.3V ATX supplies.

For engineers reviewing the AP1186T5-L-U datasheet, AP1186T5-L-U pinout, AP1186T5-L-U application, or AP1186T5-L-U equivalent, key selection criteria include dropout voltage under full load, remote sensing capability for load regulation, control pin (Vctrl) biasing requirements, and thermal resistance (ΘJC = 2.5°C/W) for heatsink design in high-current linear regulation.

Technical Context

The AP1186 employs an NPN pass transistor with externally biased Vctrl pin-separate from Vin-to eliminate base-current-related inefficiency typical of PNP LDOs. This architecture enables ultra-low dropout while maintaining fast transient response for GPU core supply applications.

Its five-terminal topology separates Vout, Vsense, Adj (GND in fixed mode), Vctrl, and Vin to support true remote sensing and independent control rail biasing. The internal 1.25V reference and ±2.5% output tolerance (at 10mA) are maintained across 0–150°C junction temperature range with built-in thermal shutdown activation above 150°C.

Key Specifications

Pinout & Package

AP1186T5-L-U uses the TO220-5L package with exposed tab electrically connected to Vout. Pin 1 = Vin, Pin 2 = Vsense, Pin 3 = Adj (GND in fixed mode), Pin 4 = Vctrl, Pin 5 = Vout. Tab serves as primary thermal path and output connection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1186K5-L-U, the T5 variant offers easier mechanical mounting and field-replaceability; compared with LT1963AEST-2.5#TRPBF, it provides superior load regulation accuracy and thermal headroom at the cost of higher design complexity due to the Vctrl rail.

Availability

AP1186T5-L-U is available at Aetrix Electronics and suitable for graphics processor core supplies, ATX motherboard auxiliary rails, industrial FPGA I/O banks, and test equipment precision references requiring stable component supply with lead-free compliance and long-lifecycle support.

Supply support for AP1186T5-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 manufacturer of discrete semiconductors and analog ICs, specializing in high-efficiency power management, signal integrity, and protection solutions for computing, industrial, and consumer markets.

The AP1186 belongs to Diodes' ultra-low dropout linear regulator product line, engineered specifically for high-current, low-voltage GPU and FPGA core supply applications where switching noise must be avoided and remote sensing is critical.

FAQ

What is the minimum required capacitor on the Vctrl pin?

The datasheet specifies a minimum 100µF aluminum electrolytic capacitor from Vctrl to ground to ensure stability and sufficient charge delivery during transient load events. Lower values risk oscillation or control loop instability, especially under 1.5A step loads. Use capacitors rated for ≥105°C and ESR ≤100mΩ.

Can AP1186T5-L-U operate without the Vsense pin connected?

Yes-when Vsense is shorted to Vout, the device operates in local-sensing mode with typical load regulation of 1%. However, remote sensing (Vsense connected at load) improves load regulation to ≤0.02%/A by compensating for PCB trace resistance, which is essential for GPU core applications.

Is the Vctrl pin required to be higher than Vin at all times?

Yes-the datasheet mandates Vctrl ≥ Vin + 1V under all operating conditions. If Vctrl drops below this threshold, the internal control circuitry loses bias, causing loss of regulation and potential output collapse. A dedicated 5V rail or boosted 3.3V supply is typically used.

How does thermal shutdown behave during sustained overload?

Thermal shutdown activates when junction temperature exceeds ~150°C, latching off the pass transistor until temperature falls below ~135°C. During repeated cycling, average output current drops significantly-designers must size heatsinks to keep steady-state TJ < 125°C at 1.5A to avoid intermittent shutdown.