STMicroelectronics LD1084D2M80R

Overview

LD1084D2M80R from STMicroelectronics is a fixed-output 8V, 5A low-dropout linear voltage regulator in D2PAK package, featuring 1.3V typical dropout at full load, ±1% output tolerance at 25°C, and internal thermal/overcurrent protection for industrial power rails and FPGA core supplies.

For engineers reviewing the LD1084D2M80R datasheet, LD1084D2M80R pinout, LD1084D2M80R application, or LD1084D2M80R equivalent, this page delivers verified electrical specs, thermal resistance data, stability requirements (10µF min output capacitor), and real-world use cases including SCSI-2 termination and high-current analog subsystems.

Technical Context

The LD1084D2M80R uses an NPN pass transistor architecture-unlike PNP-based regulators-so quiescent current flows into the load, improving efficiency. It operates across –40°C to +125°C junction temperature with internally trimmed reference voltage enabling ±1% initial accuracy.

Its dropout behavior is load-dependent: guaranteed ≤1.5V at 5A, decreasing at lower currents. The device requires only a 10µF tantalum output capacitor for stability and supports input voltages up to 30V DC, with short-circuit current limiting that scales inversely with input-to-output differential voltage.

Key Specifications

Pinout & Package

D2PAK (TO-263) package: surface-mount, single-row 3-pin thermally enhanced outline with exposed metal tab (pin 2) for heatsinking. Pin 1 = Input, Pin 2 = Ground / Tab, Pin 3 = Output.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2940CT-8.0/NOPB and TLV1117-80CDR, the LD1084D2M80R uniquely delivers 5 A continuous current with 1.3 V dropout and ±1% accuracy in a thermally optimized D2PAK-making it the sole option for high-current, precision industrial power stages.

Availability

LD1084D2M80R is available at Aetrix Electronics and suitable for industrial motor drives, FPGA power sequencing, test equipment auxiliary rails, and SCSI-2 termination requiring stable component supply with full traceability and long-lifecycle support.

Supply support for LD1084D2M80R 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 analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The LD1084 series belongs to ST's high-current linear regulator product line, engineered specifically for industrial power conversion where reliability, thermal resilience, and tight DC accuracy supersede switching efficiency.

FAQ

What is the minimum input voltage required for LD1084D2M80R to maintain regulation at 5 A?

The LD1084D2M80R requires a minimum input voltage of 9.3 V to sustain 8.0 V output at 5 A, based on its guaranteed 1.5 V maximum dropout voltage. At typical 1.3 V dropout, 9.3 V is sufficient-but design margin should include worst-case tolerance and transient droop, recommending ≥9.5 V nominal input.

Can LD1084D2M80R be used without a heatsink in a 5 A application?

Yes-if PCB copper area provides adequate thermal conduction. With R_thJC = 3°C/W and R_thJA = 62.5°C/W (D2PAK), dissipating 5 A at 1.3 V dropout (6.5 W) raises junction temperature by ~19.5°C above case. A 10 cm² 2-oz copper pour reduces effective R_thJA, often eliminating need for external heatsink in vented enclosures.

Does LD1084D2M80R require an input capacitor, and if so, what value?

Yes-an input capacitor is mandatory for stability and transient suppression. ST recommends ≥10 µF tantalum or low-ESR aluminum electrolytic placed within 10 mm of Pin 1 (IN). Ceramic capacitors alone are insufficient due to insufficient bulk capacitance; a 10 µF tantalum + 100 nF ceramic parallel combination is optimal for broadband decoupling.

How does the LD1084D2M80R's quiescent current behavior differ from traditional PNP LDOs?

Unlike PNP-based LDOs (e.g., LM2931), where quiescent current is drawn from VIN and sunk to GND-wasting power-the LD1084D2M80R's NPN architecture routes its 5–10 mA quiescent current into the load. This increases net efficiency by delivering usable current rather than dissipating it, especially beneficial in high-current applications where even small gains impact thermal design.