Diodes Incorporated AP1086D18L-U

Overview

AP1086D18L-U 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 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 system power rails.

For engineers reviewing the AP1086D18L-U datasheet, AP1086D18L-U pinout, AP1086D18L-U application, or AP1086D18L-U equivalent, key selection criteria include guaranteed 1.4V max dropout at 1.5A, thermal shutdown protection, TO252-3L package thermal resistance (θ_JA = 101°C/W), and fixed 1.8V output stability under fast load transients.

Technical Context

The AP1086D18L-U integrates an internal reference (1.25V), error amplifier, and PNP pass transistor in a fixed-output configuration. Its feedback network is factory-trimmed for 1.8V output, eliminating external resistors and reducing layout sensitivity.

It employs current-limiting and thermal shutdown circuitry that activates at 150°C junction temperature. Dropout behavior is characterized across temperature (0–125°C) and load (0–1.5A), with guaranteed 1.4V max dropout at T_J = 25°C and 125°C.

Key Specifications

Pinout & Package

AP1086D18L-U is housed in a lead-free, RoHS-compliant TO252-3L (DPAK) surface-mount package with exposed thermal pad connected internally to VOUT. The tab serves as the output terminal and must be soldered to a thermal pad on the PCB for effective heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1117D18L-U, AP1086D18L-U delivers 50% higher current capacity and better transient response; versus MIC29302WU-1.8, it offers smaller footprint, lower quiescent current, and adequate dropout for 3.3V-to-1.8V conversion without over-engineering.

Availability

AP1086D18L-U is available at Aetrix Electronics and suitable for high-speed bus termination, VGA card power rails, and embedded microcontroller core rails requiring stable component supply, consistent thermal performance, and RoHS-compliant packaging.

Supply support for AP1086D18L-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 industrial, computing, and consumer markets.

The AP1086 product line delivers cost-optimized, high-reliability LDO regulators targeting board-level voltage translation in space-constrained, thermally demanding applications such as graphics cards and embedded controllers.

FAQ

What is the minimum input voltage required for AP1086D18L-U to regulate 1.8V at 1.5A?

The device requires VIN ≥ VOUT + 1.4V = 3.2V to maintain regulation at full load. At 25°C junction temperature, the maximum dropout is guaranteed at 1.4V; derating applies above 125°C ambient due to thermal resistance (101°C/W). Input below 3.2V causes dropout mode and unregulated output.

Can AP1086D18L-U be used in adjustable mode?

No. AP1086D18L-U is a fixed-output variant with internal resistor divider trimmed for 1.8V. The "D" prefix indicates TO252-3L package and "18" denotes 1.8V output; the Adj pin is internally grounded and not configurable. For adjustable versions, refer to AP1086DXXL-U with "XX" = "AD".

Is an input capacitor required for stable operation?

While not strictly mandatory for stability, a ≥1µF ceramic input capacitor placed near the VIN pin is strongly recommended to suppress high-frequency noise and prevent input voltage sag during load transients. The datasheet specifies a 1µF input cap in typical application circuits for both fixed and adjustable configurations.

How does the TO252-3L package's thermal pad affect PCB layout?

The exposed thermal pad on the TO252-3L must be soldered to a dedicated copper pour connected to the VOUT net. Diodes Inc. recommends a 7.2mm × 2.18mm land pattern with thermal vias to inner layers. Inadequate pad area or missing vias raises θ_JA, risking thermal shutdown at >1A continuous load.