Diodes Incorporated AP1086K18L-13

Overview

AP1086K18L-13 from Diodes Incorporated is a 1.5A low dropout (LDO) positive fixed-mode voltage regulator delivering a precise 1.8V output with ≤1.4V dropout at full load, ±1.2% initial output voltage tolerance, and 60–70dB ripple rejection at 120Hz. It operates from 3.3V to 12V input and supports high-speed bus termination and low-current 3.3V logic supply in VGA cards and embedded power rails.

For engineers reviewing the AP1086K18L-13 datasheet, AP1086K18L-13 pinout, AP1086K18L-13 application, or AP1086K18L-13 equivalent, key selection considerations include dropout voltage under 1.5A load, thermal shutdown behavior, minimum 10µF output capacitance requirement, and TO263-3L package thermal resistance (θJC = 0.65°C/W for control circuitry).

Technical Context

The AP1086K18L-13 integrates a precision 1.25V reference, error amplifier, current-limit protection, and thermal shutdown circuitry in a single monolithic IC. Its feedback loop is internally configured for fixed 1.8V output-no external resistors required-enabling stable regulation with fast transient response to 0–1.5A load steps.

It uses a PNP pass transistor architecture to achieve low dropout while maintaining tight line regulation (≤0.2%) and load regulation (≤18mV over 0–1.5A). Junction-to-case thermal resistance is split between control circuitry (0.65°C/W) and power transistor (2.7°C/W), enabling effective heatsinking via the exposed tab (VOUT-connected).

Key Specifications

Pinout & Package

AP1086K18L-13 is housed in a TO263-3L (D²PAK) surface-mount package with an exposed metal tab electrically connected to VOUT for thermal conduction and mechanical anchoring. The package features gull-wing leads and RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1086D18L-13, the K-suffix TO263-3L offers superior thermal dissipation for sustained 1.5A operation; versus LD1117S18TR, AP1086K18L-13 delivers higher current, tighter tolerance, and lower dropout-making it the only viable choice for demanding 1.8V system rails.

Availability

AP1086K18L-13 is available at Aetrix Electronics and suitable for high-speed bus termination, VGA card power rails, and FPGA I/O bank regulation requiring stable component supply across industrial, computing, and embedded design cycles.

Supply support for AP1086K18L-13 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 industrial, computing, and consumer markets.

The AP1086 series belongs to Diodes' high-current LDO portfolio, engineered specifically for low-voltage, high-transient digital power rails-including bus termination, GPU I/O, and FPGA interface supplies-where dropout, noise, and thermal reliability are critical.

FAQ

What is the minimum input voltage required for AP1086K18L-13 to regulate at 1.8V?

The device requires a minimum input voltage of 3.2V to maintain regulation: 1.8V output plus the maximum 1.4V dropout voltage. Below this, output voltage drops linearly with input. At light loads (<10mA), regulation may hold down to ~2.8V due to lower dropout, but full 1.5A capability requires ≥3.2V input.

Can AP1086K18L-13 be used in adjustable mode?

No. The "K18" suffix indicates factory-masked fixed 1.8V output; the Adj pin is internally grounded and not functional for external adjustment. Only the "Adj" variant (e.g., AP1086KAL-13) supports external resistor programming of output voltage between 1.25V and VIN−1.4V.

Is a heat sink mandatory for AP1086K18L-13 operating at 1.5A?

A heat sink is not mandatory but strongly recommended for continuous 1.5A operation above 25°C ambient. With θJA = 83°C/W and 1.4V dropout, power dissipation reaches 2.1W - raising junction temperature by ~174°C above ambient without heatsinking. A 10cm² 1oz copper pour reduces θJA significantly; forced air or clip-on heatsinks further extend safe operating time.

What type of output capacitor is required for stability?

A minimum 10µF aluminum electrolytic capacitor is required from VOUT to GND for stability and transient response. Tantalum (25µF) improves ripple rejection to 60–70dB at 120Hz. Ceramic capacitors alone are insufficient due to low ESR causing phase margin loss; if used, add a 1Ω damping resistor in series or pair with ≥10µF bulk electrolytic.