STMicroelectronics LD1084V12

Overview

LD1084V12 from STMicroelectronics is a fixed-output 12 V, 5 A low-dropout linear voltage regulator in TO-220 package, featuring 1.3 V typical dropout at full load, ±1 % output tolerance at 25 °C, and internal thermal/power limiting for robust operation in industrial power rails.

For engineers reviewing the LD1084V12 datasheet, LD1084V12 pinout, LD1084V12 application, or LD1084V12 equivalent, key selection criteria include guaranteed 5 A output current, dropout performance under high-load conditions, thermal resistance (R_thJC = 3 °C/W), stability with ≥10 µF output capacitance, and compatibility with legacy 3-terminal adjustable regulator footprints.

Technical Context

The LD1084V12 employs a PNP pass transistor architecture where quiescent current flows into the load-unlike conventional PNP regulators-improving efficiency. It integrates on-chip trimming for tight output voltage accuracy and features internal current limiting and thermal shutdown.

Designed for fixed-voltage operation, it requires no external feedback resistors. Its 12 V output is specified across –40 °C to +125 °C junction temperature, with load regulation of ≤72 mV over 0–5 A and supply voltage rejection of 54–66 dB at 120 Hz with 5 A load.

Key Specifications

Pinout & Package

Supplied in TO-220 package with integral metal tab for heatsinking and electrical connection to Pin 2 (Ground). The device uses standard 3-pin through-hole mounting with center-tab grounding.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM317T and LT1084-12, the LD1084V12 offers superior current capability (5 A vs. 1.5 A/7.5 A), integrated thermal protection, and fixed 12 V output without external components-making it optimal for high-power, production-ready industrial and automotive linear regulation.

Availability

LD1084V12 is available at Aetrix Electronics and suitable for industrial PLC power supplies, test equipment main rails, and automotive body control modules requiring stable component supply and long-lifecycle support.

Supply support for LD1084V12 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and discrete devices for industrial, automotive, and consumer markets.

The LD1084xx series belongs to ST's high-current linear regulator product line, engineered specifically for applications demanding robust 5 A output, low dropout, and industrial-grade thermal reliability without switching noise.

FAQ

What is the minimum input voltage required for LD1084V12 to regulate 12 V at 5 A?

The minimum input voltage is 13.3 V, derived from the typical 1.3 V dropout voltage at 5 A load. At maximum rated current, the device requires at least this headroom to maintain regulation; operation below this threshold results in unregulated output and potential thermal stress.

Can LD1084V12 be used without an output capacitor?

No. A minimum 10 µF tantalum or ceramic output capacitor is mandatory for stability per the datasheet. Omitting it risks oscillation, output overshoot, and thermal runaway under load transients-especially with long PCB traces or inductive loads.

Is the metal tab electrically isolated from the internal circuitry?

No. The TO-220 metal tab is internally connected to Pin 2 (Ground). When mounted to a heatsink, electrical isolation (e.g., mica washer + insulating sleeve) is required unless the heatsink is grounded and referenced to system GND.

How does LD1084V12 handle short-circuit conditions?

It limits short-circuit current to 5.5–6.5 A depending on dropout voltage (VI – VO), while simultaneously activating thermal shutdown if junction temperature exceeds safe limits. This dual protection prevents destruction during sustained faults and enables automatic recovery once fault clears and temperature drops.