STMicroelectronics KD1084DT33R

Overview

KD1084DT33R from STMicroelectronics is a fixed-output 3.3 V, 5 A low-dropout linear voltage regulator in DPAK package, featuring ±2 % output tolerance at 25 °C and ±3 % over −40 °C to +125 °C, 1.3 V typical dropout at full load, and internal thermal/current limiting for industrial power rail regulation.

For engineers reviewing the KD1084DT33R datasheet, KD1084DT33R pinout, KD1084DT33R application, or KD1084DT33R equivalent, this page delivers verified electrical specs, thermal performance data, real-world use cases in embedded power supplies, and validated alternative parts with documented tolerance and dropout differences.

Technical Context

The KD1084DT33R uses an NPN-based pass transistor architecture enabling quiescent current to flow into the load-improving efficiency versus PNP regulators. It operates across −40 °C to +125 °C junction temperature with internally trimmed reference and feedback circuitry ensuring stable 3.3 V output under varying line/load conditions.

Dropout voltage remains ≤1.5 V up to 5 A output current, decreasing at lighter loads; supply voltage rejection reaches 72 dB at 120 Hz with 25 µF output capacitance, and RMS output noise is just 0.003 % of VO (10 Hz–10 kHz).

Key Specifications

Pinout & Package

Supplied in surface-mount DPAK (TO-252) package with exposed thermal pad for enhanced heat dissipation. Pinout matches industry-standard 3-terminal adjustable regulators for drop-in replacement in legacy designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LD1085V33 and ST1084CDT33, the KD1084DT33R offers the optimal balance of guaranteed full-temperature tolerance, proven thermal robustness in DPAK, and cost-effective precision for mainstream industrial power rails.

Availability

KD1084DT33R is available at Aetrix Electronics and suitable for industrial PLC I/O modules, embedded microcontroller power rails, SCSI-2 termination circuits, and industrial camera sensor interfaces requiring stable component supply and long-term manufacturability.

Supply support for KD1084DT33R 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 consumer markets since 1987.

The KD1084xx series belongs to ST's high-current linear regulator product line, engineered specifically for industrial power management where reliability, thermal resilience, and tight output tolerance across extreme temperatures are critical.

FAQ

What is the minimum input voltage required for stable 3.3 V output at 5 A?

The KD1084DT33R requires a minimum input voltage of 4.6 V to maintain regulation at 5 A due to its 1.3 V typical dropout. At worst-case 1.5 V dropout (per datasheet), 4.8 V input guarantees operation across temperature and process variation. Input must remain within absolute maximum 12 V rating.

Can the KD1084DT33R replace older 78xx-series regulators in existing designs?

Yes - it is pin-to-pin compatible with standard 3-terminal adjustable regulators like LM317 in DPAK footprint, but delivers superior performance: lower dropout (1.3 V vs. ~2 V), higher current (5 A vs. 1.5 A), and tighter tolerance. No layout change needed, though output capacitor value should be verified per application load transients.

Does this device require an external heat sink in a 5 A continuous application?

Not necessarily - with R_thJA = 100 °C/W and 5 A load at 3.3 V (16.5 W dissipation), junction temperature rise is ~1650 °C above ambient without heatsinking, which exceeds limits. However, using the DPAK thermal pad soldered to ≥250 mm² copper pour reduces effective R_thJA to ~40–50 °C/W, enabling 5 A operation at ambient ≤60 °C without added heatsink.

Is the KD1084DT33R RoHS-compliant and halogen-free?

Yes - the device is supplied in ECOPACK®-compliant DPAK packaging with lead-free second-level interconnect, fully compliant with RoHS Directive 2011/65/EU and halogen-free per IEC 61249-2-21. The inner box label and package marking confirm ECOPACK category and JEDEC JESD97 compliance.