STMicroelectronics LD1084D2T-R

Overview

LD1084D2T-R from STMicroelectronics is a 5A low-dropout positive voltage regulator in D2PAK package, delivering fixed 3.3V output with ±1% tolerance at 25°C and ±2% over –40°C to +125°C. It features 1.3V typical dropout at 5A, internal thermal and power limiting, and requires only a 10µF output capacitor for stability-used in industrial power rails, FPGA core supplies, and telecom line cards where high-current precision regulation is critical.

For engineers reviewing the LD1084D2T-R datasheet, LD1084D2T-R pinout, LD1084D2T-R application, or LD1084D2T-R equivalent, key selection factors include dropout voltage at full load, output tolerance across temperature, thermal resistance (R_thJC = 3°C/W), quiescent current behavior under varying input voltage, and compatibility with standard 3-terminal adjustable regulator footprints.

Technical Context

The LD1084D2T-R employs a PNP pass transistor architecture with on-chip trimming for tight output voltage accuracy, enabling stable 3.3V regulation across 4.9V–30V input range. Its dropout voltage remains ≤1.5V up to 5A load, and quiescent current (5–10mA) flows into the load-not wasted as in older PNP regulators-improving efficiency in high-current applications.

Thermal protection activates at junction temperatures exceeding +125°C, and the device supports operation from –40°C to +125°C ambient. The D2PAK package provides R_thJC = 3°C/W and R_thJA = 62.5°C/W, making it suitable for convection-cooled PCB layouts without forced airflow.

Key Specifications

Pinout & Package

D2PAK package (TO-263) with exposed thermal pad for enhanced heat transfer; compatible with standard 3-terminal adjustable regulator footprint (e.g., LM317), simplifying drop-in replacement in existing designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with LM1084IT-3.3/NOPB, LD1084D2T-R delivers tighter voltage accuracy and better thermal performance in D2PAK; versus TLV1117-33CDCYR, it provides 6.25× higher current capability and robust industrial temperature support-making it the sole fit for demanding 5A, 3.3V power rails.

Availability

LD1084D2T-R is available at Aetrix Electronics and suitable for industrial automation, telecom infrastructure, and automotive infotainment systems requiring stable component supply, long-lifecycle support, and guaranteed 5A continuous output capability.

Supply support for LD1084D2T-R 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, power, microcontroller, 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 and telecom applications demanding precision, reliability, and thermal resilience in fixed-voltage 3.3V/5V/12V power domains.

FAQ

What is the minimum input voltage required for LD1084D2T-R to maintain 3.3V regulation at 5A?

The minimum input voltage is 4.9V, derived from the 1.3V typical dropout voltage plus 3.3V output (3.3V + 1.3V = 4.6V), with 0.3V margin for worst-case variation. Datasheet Table 7 specifies VI ≥ 4.9V for full 5A operation at 3.3V output-below this, regulation fails or current limits activate.

Can LD1084D2T-R be used without an output capacitor?

No. A minimum 10µF tantalum or ceramic capacitor is mandatory at the output for stability, as confirmed in Section 3 ("Schematic application") and Section 5 ("Typical application"). Omitting it causes oscillation, excessive noise, and potential thermal runaway-even brief operation without CO risks device failure.

Does LD1084D2T-R support adjustable output configurations?

No. LD1084D2T-R is a fixed 3.3V output variant. Adjustable versions (e.g., LD1084V) exist in the same family and use two external resistors to set VO, but D2T-R has internal feedback network trimmed to 3.3V-no adjust pin or external resistor connections are present.

How does the thermal shutdown behave during sustained overload?

When junction temperature exceeds +125°C, internal thermal protection disables the pass transistor, dropping output to near zero. After cooldown below hysteresis threshold (~110°C), regulation automatically resumes-no manual reset required. This cycle repeats until fault condition clears, preventing permanent damage per Section 2 "Maximum ratings".