Diodes Incorporated AP1086KL-U

Overview

AP1086KL-U from Diodes Incorporated is a 1.5A low dropout (LDO) positive voltage regulator in TO220-3L package, configurable as adjustable or fixed-output (3.3V), with 1.4V max dropout at full load, ±1% load regulation, and thermal shutdown. It delivers stable 3.3V/1.5A output from 4.8–12V input for high-speed bus termination and VGA card power rails.

For engineers reviewing the AP1086KL-U datasheet, AP1086KL-U pinout, AP1086KL-U application, or AP1086KL-U equivalent, this page provides verified electrical parameters, thermal resistance (θ_JA = 86°C/W), stability requirements (≥10µF output capacitor), and fixed-mode vs adjustable-mode design trade-offs.

Technical Context

The AP1086KL-U implements a PNP-based LDO architecture with internal 1.25V reference and current-limit protection. Its dropout voltage remains ≤1.4V across 0–1.5A load at T_J = 125°C, enabling efficient regulation from 4.8V input to 3.3V output.

It requires no external compensation beyond a minimum 10µF output capacitor for stability and achieves 70dB ripple rejection at 120Hz. Thermal shutdown activates at T_J = 150°C, and junction-to-ambient thermal resistance is 86°C/W in TO220-3L without heatsink.

Key Specifications

Pinout & Package

AP1086KL-U uses TO220-3L package with exposed tab electrically connected to VOUT for thermal conduction and mechanical mounting. Pin 1 is Adj (GND in fixed mode), Pin 2 is VOUT, Pin 3 is VIN. The tab must be thermally coupled to PCB copper area or heatsink.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1117K-3.3 and LD1086V33, AP1086KL-U offers superior 1.5A capability with lowest dropout (1.4V) and highest junction temperature rating (150°C), making it optimal for space-constrained, high-load industrial and graphics applications where thermal headroom and regulation margin are critical.

Availability

AP1086KL-U is available at Aetrix Electronics and suitable for high-speed bus termination, VGA card logic supply, and embedded system core logic requiring stable component supply with guaranteed 1.5A output and 150°C junction temperature rating.

Supply support for AP1086KL-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 cost-sensitive, high-current applications such as graphics cards, embedded controllers, and bus termination where precision, thermal robustness, and fixed-voltage simplicity are essential.

FAQ

What is the minimum input voltage required for AP1086KL-U to regulate 3.3V at full 1.5A load?

The AP1086KL-U requires VIN ≥ VOUT + 1.4V to maintain regulation at full load. For 3.3V output, minimum input is 4.7V. Below this, dropout occurs and output voltage drops linearly with input. This value is guaranteed across 0–125°C junction temperature per DS31028 Rev. 6-2.

Can AP1086KL-U be used in adjustable mode despite its fixed 3.3V marking?

No. AP1086KL-U is factory-configured as a fixed 3.3V output device. The "KL" suffix denotes TO220-3L package and 3.3V fixed output; adjustable versions use "KL-ADJ" or no voltage code. Internal resistor network is laser-trimmed during manufacturing and cannot be reconfigured externally.

Is an input capacitor required for stable operation of AP1086KL-U?

While not strictly required for stability, a ≥1µF ceramic input capacitor placed near the VIN pin is strongly recommended to suppress high-frequency noise and prevent input sag during load transients. The datasheet specifies that VIN must remain ≥1.4V above VOUT during transients - input capacitance helps maintain that margin.

How does the TO220-3L package's thermal performance compare to TO263-3L for AP1086KL-U?

AP1086KL-U (TO220-3L) has θ_JA = 86°C/W, while TO263-3L variants (e.g., AP1086KK-3.3) have θ_JA = 83°C/W - a marginal 3°C/W improvement. However, TO220-3L offers superior mechanical rigidity and easier heatsink mounting, making it preferred for industrial applications where vibration resistance and thermal cycling reliability are prioritized over minimal thermal resistance.