STMicroelectronics LD1084V18

Overview

LD1084V18 from STMicroelectronics is a fixed-output, low-dropout linear voltage regulator delivering up to 5A output current with 1.8V nominal output, ±1% tolerance at 25°C, 1.3V typical dropout at 5A, and operation across –40°C to +125°C. It serves as a primary power rail regulator in industrial motor drives, telecom power modules, and high-current FPGA/ASIC core supply circuits.

For engineers reviewing the LD1084V18 datasheet, LD1084V18 pinout, LD1084V18 application, or LD1084V18 equivalent, key selection criteria include guaranteed 5A output capability under thermal-limited conditions, tight ±1% initial accuracy, minimal external capacitance requirement (10µF), and TO-220/D2PAK package compatibility with legacy 3-terminal regulators.

Technical Context

The LD1084V18 uses an NPN pass transistor architecture-unlike PNP-based regulators-so quiescent current flows into the load rather than being wasted, improving efficiency at light loads. Its internal trimming achieves ±1% output voltage accuracy at 25°C and ±2% over full temperature range.

Thermal protection and current limiting are fully integrated; dropout voltage remains stable at ≤1.5V across 0–5A load and –40°C to +125°C junction temperature. The device requires only a single 10µF output capacitor for stability and supports input voltages up to 30V DC.

Key Specifications

Pinout & Package

Available in TO-220 (3-pin), D2PAK, and D2PAK/A surface-mount packages. All variants use identical 3-terminal configuration: Input (IN), Output (OUT), and Ground (GND). Thermal pad on D2PAK/D2PAK/A is electrically connected to GND and must be soldered for rated power dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM350T-1.8/NOPB and TLV1117-18CDCYR, the LD1084V18 uniquely delivers 5A output with 1.3V dropout and ±1% accuracy in through-hole and power-SMD packages-enabling higher integration density and eliminating secondary regulation stages in mid-power systems.

Availability

LD1084V18 is available at Aetrix Electronics and suitable for industrial motor drives, telecom line cards, FPGA power supplies, and automotive ADAS camera modules requiring stable component supply with long-term lifecycle assurance.

Supply support for LD1084V18 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 silicon solutions for automotive, industrial, and power management applications.

The LD1084 series belongs to ST's high-current linear regulator product line, engineered specifically for industrial and telecom systems demanding robust thermal performance, tight DC accuracy, and simplified layout with minimal external components.

FAQ

What is the minimum input voltage required for LD1084V18 to regulate at full 5A?

The LD1084V18 requires a minimum input voltage of 3.1V to sustain 5A output while maintaining regulation. This is derived from its 1.3V typical dropout voltage added to the 1.8V nominal output. At higher ambient temperatures or with poor heatsinking, the effective dropout may increase slightly-designers should verify thermal margin using R_thJA = 50°C/W (TO-220) or 62.5°C/W (D2PAK) in worst-case conditions.

Can LD1084V18 be used in parallel for >5A output?

No-LD1084V18 is not designed for parallel operation. Its output voltage tolerance (±1%) and load regulation (7mV) prevent natural current sharing between units. Attempting parallel connection risks thermal runaway and uneven current distribution. For >5A requirements, ST recommends using a single LD1084V18 with adequate heatsinking or selecting a higher-current switching solution.

Is an input capacitor required for stability?

An input capacitor is recommended but not strictly required for stability-unlike many LDOs, the LD1084V18 remains stable with only a 10µF output capacitor. However, a 10µF–47µF low-ESR input capacitor (e.g., tantalum or ceramic) improves transient response to upstream supply variations and reduces noise coupling from preceding DC/DC stages.

Does LD1084V18 support reverse-voltage protection?

No-the LD1084V18 lacks built-in reverse-voltage protection. If input polarity reversal is possible in the system (e.g., during hot-swap or battery insertion), an external series Schottky diode (rated ≥5A, V_F < 0.4V) must be added between the source and IN pin to prevent device damage. This adds ~0.3V overhead to the dropout requirement.