Diodes Incorporated AP1186T5-50G-U

Overview

AP1186T5-50G-U from Diodes Incorporated is a 1.5A ultra-low dropout positive fixed-mode linear regulator with 5.0V output, TO220-5L package, 0.38V max dropout at 1.5A, built-in thermal shutdown and current limiting, designed for stable 5V supply in ATX-based motherboard power rails feeding graphics chipsets and high-speed logic.

For engineers reviewing the AP1186T5-50G-U datasheet, AP1186T5-50G-U pinout, AP1186T5-50G-U application, or AP1186T5-50G-U equivalent, key selection criteria include dropout voltage under full load, remote sensing capability via Vsense pin, Vctrl biasing requirements, thermal resistance (ΘJC = 2.5°C/W), and compatibility with 100µF minimum output capacitance for stability.

Technical Context

The AP1186T5-50G-U uses an NPN pass transistor architecture with externally biased Vctrl pin-separate from Vin-to achieve sub-0.4V dropout while avoiding base-current losses typical of PNP regulators. Its five-terminal configuration enables true remote sensing via dedicated Vsense and Adj pins.

It operates in fixed-output mode (5.0V) with internal reference trimming (±2% over temperature), supports fast transient response to 300–500ns current steps, and requires Vctrl ≥ Vin + 1V for regulation. Stability relies on ≥100µF output capacitor with 50–100mΩ ESR.

Key Specifications

Pinout & Package

Package: TO220-5L (lead-free, RoHS-compliant, tab connected to Vout). Thermal resistance Θ_JC = 2.5°C/W. Tab is electrically connected to Vout and serves as primary heat path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1186K5-50G-U, the T5 variant offers through-hole assembly compatibility and identical thermal performance but requires manual or wave-solder process; versus LM2940CT-5.0, it delivers 50% higher current, 24% lower dropout, and remote sensing-justifying its use where load accuracy and dynamic response are critical.

Availability

AP1186T5-50G-U is available at Aetrix Electronics and suitable for graphics core power, ATX motherboard rail regulation, industrial control I/O, and FPGA configuration supply requiring stable component supply, long-term lifecycle support, and RoHS-compliant lead-free packaging.

Supply support for AP1186T5-50G-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 computing, industrial, and consumer markets.

The AP1186 product line targets high-current, ultra-low-dropout linear regulation in space-constrained ATX and embedded systems-designed specifically to replace inefficient PNP-based regulators while maintaining compatibility with legacy 5V supply architectures.

FAQ

What is the purpose of the Vctrl pin on AP1186T5-50G-U?

The Vctrl pin supplies bias voltage to the internal control circuitry and base drive of the NPN pass transistor. It must be at least 1V higher than Vin to ensure proper regulation. This architecture eliminates base-current losses seen in PNP LDOs, enabling lower dropout and higher efficiency. Typical implementation connects Vctrl to the ATX 5V rail when regulating from 3.3V input.

Can AP1186T5-50G-U be used without remote sensing?

Yes-Vsense can be tied directly to Vout for local regulation. However, doing so forfeits the primary advantage of the device: compensation for PCB trace voltage drop. For applications where load is within 10mm of the regulator and trace resistance is <10mΩ, local sensing is acceptable. Otherwise, routing Vsense to the load improves regulation accuracy by up to 100mV.

What is the minimum output capacitance required for stability?

The AP1186T5-50G-U requires a minimum of 100µF aluminum electrolytic capacitor at the Vout pin with 50–100mΩ ESR for guaranteed stability. Ceramic capacitors alone are insufficient due to near-zero ESR; a parallel RC network or hybrid (polymer + electrolytic) approach may be used if low-profile design is needed.

Does AP1186T5-50G-U support adjustable output voltage?

No-AP1186T5-50G-U is factory-trimmed for fixed 5.0V output. The "50" in the part number denotes 5.0V; adjustable versions use suffix "-ADJ" (e.g., AP1186T5-ADJG-U) and require external resistor dividers on the Adj and Vsense pins per the V_out = 1.25V × (1 + R2/R1) formula.