Diodes Incorporated AP1086T18G-U

Overview

AP1086T18G-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, thermal shutdown, and current limiting. It uses TO220-3L packaging with VOUT-connected tab, supports 4.8–12V input, and targets high-speed bus termination and low-current 3.3V/1.8V logic supplies in VGA cards and embedded systems.

For engineers reviewing the AP1086T18G-U datasheet, AP1086T18G-U pinout, AP1086T18G-U application, or AP1086T18G-U equivalent, key selection criteria include dropout voltage at 1.5A, output voltage tolerance (±1.2% at 10mA), thermal resistance (θ_JA = 86°C/W), ripple rejection (70dB at 120Hz), and minimum 10µF output capacitance requirement for stability.

Technical Context

The AP1086T18G-U implements a fixed-output LDO architecture with internal reference (1.25V), error amplifier, and PNP pass transistor-enabling regulation with only 1.4V VIN–VOUT differential. Its feedback network is factory-trimmed for 1.8V output, eliminating external resistors required in adjustable variants.

Thermal shutdown activates at 150°C junction temperature, and current limiting engages at ≥1.6A under 5V VIN–VOUT differential. Stability relies on ≥10µF aluminum electrolytic output capacitor placed adjacent to the VOUT pin, with no need for ESR tuning.

Key Specifications

Pinout & Package

AP1086T18G-U uses TO220-3L package with exposed metal tab electrically connected to VOUT for thermal conduction and mechanical mounting. Pin 1 is Adj/GND (grounded internally for fixed mode), Pin 2 is VOUT, Pin 3 is VIN. The tab must be isolated from chassis ground unless VOUT is referenced to system ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1117T18G-U and TLV1117-18CKR, the AP1086T18G-U uniquely supports 1.5A continuous output with 1.4V dropout and ±1.2% accuracy in TO220-3L-making it the only option among the three qualified for high-current VGA and FPGA I/O bank applications requiring robust thermal handling.

Availability

AP1086T18G-U is available at Aetrix Electronics and suitable for VGA graphics card power, FPGA I/O bank supply, PCIe slot termination, and embedded microcontroller core supply requiring stable component supply, long-lifecycle availability, and industrial-grade thermal performance.

Supply support for AP1086T18G-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 high-current, low-dropout linear regulators optimized for noise-sensitive, thermally demanding applications such as graphics subsystems and programmable logic power domains.

FAQ

What is the minimum input voltage required for AP1086T18G-U to regulate at 1.8V?

The AP1086T18G-U requires VIN ≥ VOUT + 1.4V to maintain regulation, so minimum input is 3.2V. However, the datasheet specifies 4.8V minimum for guaranteed 1.8V output across temperature and load-this accounts for worst-case dropout (1.4V), tolerance stack-up, and transient headroom needed for stability under 1.5A load steps.

Can AP1086T18G-U be used without an output capacitor?

No. A minimum 10µF aluminum electrolytic capacitor is mandatory between VOUT and GND for loop stability and transient response. Omitting it causes oscillation, output overshoot, and potential device failure during load transients. Tantalum or polymer capacitors may be used but must meet ESR and capacitance requirements per the datasheet.

Is the metal tab on AP1086T18G-U electrically isolated?

No-the TO220-3L tab is internally connected to Pin 2 (VOUT). When mounting to a heatsink or chassis, electrical isolation via mica washer or insulating pad is required unless the heatsink is referenced to the 1.8V output rail. Failure to isolate risks short-circuiting VOUT to ground or other potentials.

Does AP1086T18G-U support adjustable output configurations?

No. AP1086T18G-U is a fixed 1.8V variant. Adjustable versions use suffix "-Adj" (e.g., AP1086TADJG-U) and require external resistor dividers on the Adj pin. This part has the Adj pin internally grounded and trimmed for 1.8V-no external components or configuration pins enable voltage adjustment.