STMicroelectronics LD1084V33

Overview

LD1084V33 from STMicroelectronics is a fixed-output 3.3 V, 5 A low-dropout linear voltage regulator in TO-220 and D2PAK packages, featuring ±1% output tolerance at 25°C, 1.3 V typical dropout at full load, internal thermal and current limiting, and operation from –40°C to +125°C. It powers high-current digital logic rails in industrial PLCs, telecom power modules, and embedded computing systems requiring stable 3.3 V supply under variable load.

For engineers reviewing the LD1084V33 datasheet, LD1084V33 pinout, LD1084V33 application, or LD1084V33 equivalent, key selection criteria include dropout voltage at 5 A, output voltage accuracy over temperature, thermal resistance (R_thJC = 3°C/W in TO-220), minimum required output capacitance (10 µF), and compatibility with legacy adjustable regulator footprints.

Technical Context

The LD1084V33 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 bandgap reference and trimmed resistor network enable tight ±1% initial output tolerance.

It integrates thermal shutdown and current limiting that dynamically reduce output current above safe junction temperatures or during overload, ensuring robustness without external protection circuitry. Dropout voltage remains stable across temperature and load due to low-impedance internal biasing and optimized loop compensation.

Key Specifications

Pinout & Package

LD1084V33 is available in TO-220 (3-pin, vertical mount), D2PAK (3-pin, surface-mount), and D2PAK/A (3-pin, enhanced thermal variant) packages. All variants share identical pin assignment: Pin 1 = Input, Pin 2 = Ground, Pin 3 = Output.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2940CT-3.3 and LT1963AEST-3.3, the LD1084V33 uniquely delivers 5 A output with 1.3 V dropout in through-hole and surface-mount packages-making it the only viable choice for high-current 3.3 V regulation where thermal design permits discrete heatsinking and board space accommodates TO-220 or D2PAK footprints.

Availability

LD1084V33 is available at Aetrix Electronics and suitable for industrial automation, telecom infrastructure, and embedded computing applications requiring stable component supply, long-lifecycle support, and guaranteed 5 A delivery under thermal constraint.

Supply support for LD1084V33 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, MCU, 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 power systems demanding robust 3–12 V fixed or adjustable outputs with tight tolerance, low dropout, and integrated protection.

FAQ

What is the minimum input voltage required for LD1084V33 to regulate 3.3 V at 5 A?

The minimum input voltage is 4.6 V, calculated as 3.3 V + 1.3 V (typical dropout at 5 A). The datasheet specifies VI ≥ 4.9 V for guaranteed 5 A operation across temperature and process variation, accounting for worst-case 1.5 V dropout and margin for ripple and tolerances.

Can LD1084V33 be used without an output capacitor?

No. A minimum 10 µF tantalum or ceramic capacitor is mandatory for stability per the datasheet. Omitting it causes oscillation and output voltage collapse under load. The capacitor must be placed within 5 mm of the OUT and GND pins, with low-ESR (<1 Ω) and low-ESL construction.

How does LD1084V33 handle short-circuit conditions?

It limits output current to 5.5–6.5 A when VI − VO = 5 V, then activates thermal shutdown if junction temperature exceeds ~165°C. During sustained short, it cycles between current limit and thermal shutdown-preventing destruction but requiring external fusing for safety-critical designs.

Is LD1084V33 RoHS-compliant and halogen-free?

Yes. STMicroelectronics certifies LD1084V33 as RoHS-compliant and ECOPACK®-qualified, with lead-free second-level interconnects and halogen-free molding compounds meeting IEC 61249-2-21 standards, as documented in ST's official package mechanical data sheets.