STMicroelectronics LD1084D2M50R

Overview

LD1084D2M50R from STMicroelectronics is a 5A low-dropout positive voltage regulator with fixed 5.0V output, housed in a D2PAK surface-mount package. It delivers ±1% output voltage tolerance at 25°C, maintains regulation down to 1.3V dropout at full 5A load, and operates across –40°C to +125°C junction temperature. It is used in industrial power supplies, FPGA core voltage rails, and telecom line cards requiring stable high-current DC regulation.

For engineers reviewing the LD1084D2M50R datasheet, LD1084D2M50R pinout, LD1084D2M50R application, or LD1084D2M50R equivalent, this page provides verified technical context, validated pin functions, real-world application constraints, and confirmed alternative parts for 5V/5A LDO replacement scenarios - including thermal derating guidance, minimum capacitor requirements (10µF), and compatibility with legacy adjustable regulator footprints.

Technical Context

The LD1084D2M50R uses an NPN pass transistor architecture, enabling quiescent current to flow into the load rather than being wasted as bias current-improving efficiency over PNP-based regulators. Its internal trimming achieves ±1% initial output accuracy and supports operation with only a 10µF output capacitor for stability.

It integrates thermal shutdown and current limiting, with junction-to-case thermal resistance of 3°C/W in D2PAK. Dropout voltage remains ≤1.5V up to 5A across –40°C to +125°C, and supply voltage rejection exceeds 60dB at 120Hz with 5A load and 25µF output capacitance.

Key Specifications

Pinout & Package

D2PAK (TO-263) package: thermally enhanced surface-mount outline with exposed metal pad for heatsinking; compatible with standard TO-220 footprint adapters.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 5V/5A LDO applications.

Compared with LM350T and LT1084CK-5, the LD1084D2M50R offers the lowest dropout (1.3V) and tightest tolerance (±1%) in D2PAK, enabling higher efficiency and smaller input capacitors in space- and thermally constrained 5V/5A applications.

Availability

LD1084D2M50R is available at Aetrix Electronics and suitable for industrial automation, telecom infrastructure, and embedded computing applications requiring stable component supply, long-lifecycle support, and RoHS-compliant D2PAK packaging.

Supply support for LD1084D2M50R 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 markets.

The LD1084 series belongs to ST's high-current linear regulator product line, engineered specifically for industrial and telecom applications demanding low dropout, high accuracy, and rugged thermal performance in compact surface-mount packages.

FAQ

What is the minimum input voltage required for LD1084D2M50R to regulate 5.0V at 5A?

The minimum input voltage is 6.3V: 5.0V output plus maximum dropout of 1.5V at 5A load, per datasheet Table 3–12. At typical 1.3V dropout, 6.3V suffices, but designs must allow for worst-case 1.5V to ensure regulation across temperature and process variation.

Can LD1084D2M50R be used with ceramic output capacitors?

Yes - the device is stable with ≥10µF X7R/X5R ceramic capacitors (ESR ≥5mΩ). Unlike older LDOs, it does not require ESR-based damping; however, a 1µF ceramic in parallel with the main 10µF improves high-frequency transient response.

How does the D2PAK package affect thermal performance compared to TO-220?

D2PAK offers R_thJC = 3°C/W (same as TO-220), but its surface-mount construction relies entirely on PCB copper for heatsinking. Achieving full 5A requires ≥25 cm² of 2-oz copper connected to the exposed pad - unlike TO-220, which can use an external heatsink.

Is LD1084D2M50R pin-compatible with adjustable versions of the LD1084?

No - LD1084D2M50R is a 3-pin fixed-output variant (VIN, GND, VOUT), while adjustable versions (e.g., LD1084V) have ADJ pin instead of GND. They share the same D2PAK footprint but differ electrically and cannot be interchanged without circuit modification.