Diodes Incorporated AP1086DL-U

Overview

AP1086DL-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 protection. It delivers stable 3.3V/1.5A output from 4.8–12V input for high-speed bus termination and logic supply in VGA cards and embedded systems.

For engineers reviewing the AP1086DL-U datasheet, AP1086DL-U pinout, AP1086DL-U application, or AP1086DL-U equivalent, this page provides verified technical context, real-world design meaning of specifications, validated pin functions, application-specific implementation guidance, and confirmed alternative parts with documented functional differences.

Technical Context

The AP1086DL-U implements a PNP-based LDO architecture with internal 1.25V reference and feedback loop enabling precise output regulation across input voltages from 4.8V to 12V. Its dropout voltage remains ≤1.4V at 1.5A load, supporting efficient conversion for 3.3V rail generation where input headroom is constrained.

It integrates current limiting (1.6A typical), thermal shutdown (150°C junction limit), and requires ≥10µF output capacitance for stability. The device operates over 0–125°C junction temperature range and exhibits 60–70dB ripple rejection at 120Hz with 25µF tantalum output capacitor.

Key Specifications

Pinout & Package

AP1086DL-U uses TO220-3L package with exposed tab electrically connected to VOUT for enhanced thermal conduction. Pin 1 is Adj (GND in fixed mode), Pin 2 is VOUT, Pin 3 is VIN. Tab must be soldered to a thermal pad or heatsink.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1086DL-U, AP1086K33G-13 offers superior thermal performance in SMT layouts but requires PCB redesign, while LD1086DT33TR trades 0.1V higher dropout for alternate sourcing-both require validation of thermal margins and transient behavior in the target application.

Availability

AP1086DL-U is available at Aetrix Electronics and suitable for high-speed bus termination, VGA graphics card power, and low-current 3.3V logic supply applications requiring stable component supply across extended production lifecycles.

Supply support for AP1086DL-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 power management, signal integrity, and protection solutions for computing, industrial, and consumer markets.

The AP1086 series belongs to Diodes' LDO voltage regulator product line, engineered specifically for low-noise, high-current 3.3V and other logic rail applications where tight regulation, fast transient response, and thermal robustness are essential.

FAQ

What is the minimum input voltage required for AP1086DL-U to regulate 3.3V output?

The AP1086DL-U requires VIN ≥ VOUT + 1.4V to maintain regulation, so minimum input is 4.7V. At lower inputs, dropout occurs and output drops linearly with VIN. This value is guaranteed across temperature and load per datasheet Section "Dropout Voltage" (1.3V typ., 1.4V max at 1.5A).

Can AP1086DL-U be used in adjustable mode?

No - AP1086DL-U is factory-configured as a fixed 3.3V output device. The "DL" suffix denotes TO220-3L package with fixed 3.3V option; adjustable versions use "D", "K", or "T" prefixes with no voltage code (e.g., AP1086T-U). Pin 1 (Adj) is internally grounded and must not be externally biased.

What output capacitor is required for stability?

A minimum 10µF aluminum electrolytic capacitor is required from VOUT to GND for stability and transient response. For improved high-frequency performance, a 100µF bulk capacitor (as shown in Typical Application Circuit) is recommended - ceramic capacitors alone are insufficient due to ESR requirements specified in the datasheet.

Is heatsinking mandatory for 1.5A operation?

Yes - with θ_JA = 86°C/W and 150°C max junction temperature, even at ambient 25°C, power dissipation >1.45W (e.g., 5V→3.3V @1.5A = 2.55W) exceeds safe limits without heatsinking. A heatsink reducing θ_JA to ≤40°C/W is required for continuous 1.5A operation per thermal calculations in datasheet Section "Thermal Design".