Diodes Incorporated AP1117D18L-U

Overview

AP1117D18L-U from Diodes Incorporated is a 1A low-dropout linear voltage regulator in fixed 1.8V output mode, housed in a TO252-3L (DPAK) surface-mount package. It delivers stable 1.8V supply with ≤1.4V dropout at full 1A load, supports input voltages from 3.3V to 12V, and integrates thermal shutdown and current limiting - designed for powering 1.8V logic rails in FPGA I/O banks, DDR memory termination, and embedded microcontroller core supplies.

For engineers reviewing the AP1117D18L-U datasheet, AP1117D18L-U pinout, AP1117D18L-U application, or AP1117D18L-U equivalent, key selection criteria include dropout voltage under 1A load, thermal resistance (θ_JA = 73°C/W), fixed-output accuracy (±2% over temperature), and compatibility with standard 10µF/22µF tantalum or ceramic output capacitors.

Technical Context

The AP1117D18L-U employs a PNP pass transistor architecture enabling low dropout operation while maintaining fast transient response to load steps up to 1A. Its internal bandgap reference (1.25V nominal) and error amplifier regulate output via feedback from the VOUT pin, with no external resistors required in fixed-mode configuration.

Thermal protection activates at 150°C junction temperature, cycling output off/on during overload or high ambient conditions. Ripple rejection reaches 60–70dB at 180Hz with 25µF tantalum output capacitance, making it suitable for noise-sensitive analog and mixed-signal subsystems.

Key Specifications

Pinout & Package

AP1117D18L-U uses the TO252-3L (DPAK) thermally enhanced surface-mount package with exposed thermal tab electrically connected to VOUT. The tab must be soldered to a large copper pour 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 MCP1700T-1802E/MB and TLV1117-18CDCY, AP1117D18L-U uniquely balances 1A delivery, 1.4V dropout, and TO252-3L thermal performance - making it optimal for space-constrained, medium-power 1.8V applications where both current and thermal efficiency matter.

Availability

AP1117D18L-U is available at Aetrix Electronics and suitable for FPGA power delivery, DDR termination, microcontroller core supply, and industrial sensor interface applications requiring stable component supply and long-term manufacturability.

Supply support for AP1117D18L-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 communications markets.

The AP1117 series belongs to Diodes' precision LDO regulator product line, engineered for cost-effective, thermally robust local regulation in space-constrained embedded systems - particularly targeting logic supply and bus termination roles.

FAQ

What is the minimum input voltage required for AP1117D18L-U to maintain regulation?

The device requires VIN ≥ VOUT + 1.3V to regulate properly, so minimum input is 3.1V. However, datasheet testing specifies 3.3V minimum for guaranteed 1.8V output accuracy and load regulation performance across temperature and current range.

Can AP1117D18L-U be used with ceramic output capacitors?

Yes - it is stable with 10µF to 22µF ceramic capacitors having ESR between 0.15Ω and 20Ω. This eliminates reliance on polarized tantalum or aluminum electrolytic types, improving reliability and reducing board area.

How does thermal shutdown behave during sustained overload?

When junction temperature reaches ~150°C, the regulator disables output and remains off until die cools by ~20°C, then resumes regulation. This hiccup-mode behavior prevents thermal runaway while allowing automatic recovery without manual reset.

Is AP1117D18L-U RoHS compliant and lead-free?

Yes - the "L" suffix denotes lead-free finish and RoHS compliance per EU Directive 2002/95/EC, with exemptions applied as documented in Diodes' lead-free policy. The TO252-3L package uses green molding compound (no Br/Sb).