Diodes Incorporated AP1186T5-18G-U

Overview

AP1186T5-18G-U from Diodes Incorporated is a 1.5A ultra-low dropout positive voltage regulator in TO220-5L package, fixed at 1.8V output, with 0.38V max dropout at 1.5A load, remote sensing capability via Vsense pin, and integrated thermal shutdown. It delivers stable power to graphics chipsets requiring 2.4–2.7V supplies from 3.3V ATX rails.

For engineers reviewing the AP1186T5-18G-U datasheet, AP1186T5-18G-U pinout, AP1186T5-18G-U application, or AP1186T5-18G-U equivalent, key selection criteria include dropout voltage under full load, remote sense accuracy, thermal shutdown threshold, control pin (Vctrl) biasing requirements, and minimum output capacitance for stability.

Technical Context

The AP1186T5-18G-U uses an NPN pass transistor architecture with externally biased Vctrl pin-enabling lower dropout than standard PNP LDOs while avoiding base current losses. Its separate Vsense and Vout pins enable true remote voltage regulation at the load point, compensating for PCB trace IR drop.

It operates with Vin ≥ Vout + 0.38V and requires Vctrl ≥ Vin + 1V for full regulation; output stability mandates ≥100µF aluminum electrolytic capacitor with 50–100mΩ ESR. The device maintains ±1% load regulation across 0–1.5A at 25°C and achieves 60–70dB ripple rejection at 120Hz.

Key Specifications

Pinout & Package

AP1186T5-18G-U is housed in a TO220-5L thermally enhanced through-hole package with exposed tab electrically connected to Vout. The tab serves as primary heat path and must be mounted to a heatsink or copper pour.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1186K5-18G-U, the TO220-5L variant offers superior thermal dissipation in open-frame or heatsinked environments; versus TPS7A4701RGWR, it delivers tighter load regulation, higher PSRR, and true remote sensing-critical for high-speed digital loads where voltage droop at the die causes timing violations.

Availability

AP1186T5-18G-U is available at Aetrix Electronics and suitable for graphics card power delivery, FPGA I/O bank regulation, and industrial camera sensor biasing requiring stable component supply, long-lifecycle availability, and RoHS-compliant lead-free packaging.

Supply support for AP1186T5-18G-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 company specializing in discrete, analog, and mixed-signal ICs, with design centers in Asia, Europe, and the U.S., serving industrial, computing, and consumer markets.

The AP1186 product line targets high-current, ultra-low-dropout regulation for graphics, FPGA, and SoC applications where efficiency, noise, and transient response outweigh switching complexity - emphasizing precision, thermal resilience, and layout flexibility.

FAQ

What is the minimum input voltage required for AP1186T5-18G-U to regulate at full 1.5A load?

The minimum input voltage is 2.18V (1.8V + 0.38V max dropout), but per datasheet test conditions, Vin must be ≥2.3V for guaranteed 1.5A operation at 25°C. At elevated temperatures or with marginal heatsinking, ≥2.5V is recommended to maintain regulation margin during transient peaks.

Can the Vsense pin be left unconnected if remote sensing is not needed?

No - the Vsense pin must be connected directly to the Vout pin (not just to the output capacitor) for proper internal feedback loop operation. Leaving it floating or unconnected causes regulation failure and potential output instability, even in local-sensing configurations.

Is a heatsink mandatory for continuous 1.5A operation in TO220-5L package?

Yes - with Θ_JA ≈ 35°C/W and typical power dissipation of ~1.2W (at Vin=3.3V, Vout=1.8V), junction temperature exceeds 125°C at 25°C ambient without heatsinking. A 10°C/W heatsink or ≥2 sq-in copper pour is required for reliable 1.5A continuous operation.

Does AP1186T5-18G-U support reverse-voltage protection or input overvoltage clamping?

No - the device lacks built-in reverse-voltage or overvoltage protection. Absolute maximum Vin is 16V; exceeding this risks permanent damage. External TVS diodes on Vin and series Schottky diodes on input are recommended for systems with hot-swap or battery-backup scenarios.