Diodes Incorporated AP1086T18L-U

Overview

AP1086T18L-U from Diodes Incorporated is a fixed-output 1.8V, 1.5A low dropout linear regulator in TO220-3L package with 1.4V maximum dropout at full load, ±1.2% output voltage tolerance at 25°C, and integrated thermal shutdown. It delivers stable power to low-voltage logic circuits including 3.3V/1.8V FPGA I/O banks and VGA card core supplies.

For engineers reviewing the AP1086T18L-U datasheet, AP1086T18L-U pinout, AP1086T18L-U application, or AP1086T18L-U equivalent, key selection criteria include dropout voltage under 1.4V at 1.5A, guaranteed load regulation ≤33mV across 0–1.5A, thermal resistance θ_JA = 86°C/W (TO220), and compatibility with ≥10µF aluminum electrolytic output capacitance.

Technical Context

The AP1086T18L-U implements a bandgap-referenced error amplifier driving a PNP pass transistor, enabling fast transient response to load steps up to 1.5A with <±40mV deviation. Its internal 1.25V reference and fixed resistor network set V_OUT = 1.8V without external components.

Thermal shutdown activates at T_J = 150°C, and current limiting holds output current ≤1.6A when (V_IN−V_OUT) = 5V. Stability requires ≥10µF output capacitance with ESR ≤1Ω; ripple rejection reaches 70dB at 120Hz with 25µF tantalum.

Key Specifications

Pinout & Package

AP1086T18L-U uses the TO220-3L package with exposed tab electrically connected to V_OUT, enabling direct heatsinking to chassis ground or dedicated thermal plane. The tab must be isolated from other potentials unless referenced to V_OUT.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1086K18L-13, the AP1086T18L-U offers identical electrical specs but trades surface-mount flexibility for lower assembly cost and simplified heatsinking via through-hole mounting; versus LD1117S18TR, it provides +50% current capacity and mandatory thermal protection critical for industrial reliability.

Availability

AP1086T18L-U is available at Aetrix Electronics and suitable for FPGA power delivery, VGA graphics subsystems, industrial PLC I/O modules, and embedded camera sensor interfaces requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for AP1086T18L-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 AP1086 product line delivers low-dropout linear regulators optimized for high-current, low-voltage logic supplies in space-constrained and thermally demanding applications such as graphics cards and programmable logic devices.

FAQ

What is the minimum input voltage required for AP1086T18L-U to regulate at 1.8V output?

The device requires VIN ≥ VOUT + 1.4V = 3.2V to maintain regulation at full 1.5A load. At lighter loads, dropout decreases - e.g., 1.3V at 1A - but design margin should retain 3.2V minimum for worst-case operation across temperature and tolerance.

Can AP1086T18L-U operate without an output capacitor?

No. A minimum 10µF aluminum electrolytic capacitor is mandatory between VOUT and GND for stability. Omitting it causes oscillation and output voltage collapse due to loss of frequency compensation; tantalum or ceramic capacitors require careful ESR matching per datasheet Figure 12.

Is the tab on AP1086T18L-U electrically connected, and how should it be handled?

Yes, the TO220-3L tab is internally connected to VOUT. It must be electrically isolated from chassis ground unless the system design references VOUT to chassis. When heatsinking, use insulating pads or shoulder washers to prevent short circuits while maintaining thermal contact.

Does AP1086T18L-U support remote sensing for improved load regulation?

No. As a 3-terminal LDO, it lacks a separate sense pin. Load regulation is specified at the output pin (1/18″ from package), so PCB trace resistance between VOUT and load introduces additional voltage drop - keep high-current traces short and wide to minimize this effect.