STMicroelectronics LD1086D2T33TR

Overview

LD1086D2T33TR from STMicroelectronics is a fixed-output 3.3 V, 1.5 A low-dropout linear voltage regulator in D²PAK package, featuring ±1% output tolerance at 25 °C, 1.3 V typical dropout at full load, and internal thermal/overcurrent protection. It delivers stable power to microcontroller cores, FPGA I/O banks, and industrial sensor interfaces where input-to-output differential is constrained.

For engineers reviewing the LD1086D2T33TR datasheet, LD1086D2T33TR pinout, LD1086D2T33TR application, or LD1086D2T33TR equivalent, key selection criteria include dropout voltage under 1.5 A load, output accuracy across –40 °C to 125 °C, quiescent current behavior, stability with 10 µF output capacitance, and thermal resistance (R_thJC = 3 °C/W) for surface-mount thermal management.

Technical Context

The LD1086D2T33TR implements an NPN-based LDO architecture with on-chip trimmed bandgap reference (1.25 V), enabling tight output regulation without external feedback resistors. Its adjust pin is internally connected to ground for fixed-voltage variants, eliminating external component count while retaining compatibility with adjustable-regulator PCB footprints.

Thermal foldback and current limiting are implemented via integrated sensing circuits that dynamically reduce output current above safe junction temperature (150 °C) or short-circuit conditions. Dropout voltage remains stable across temperature due to matched transistor design and curvature-compensated reference.

Key Specifications

Pinout & Package

D²PAK (TO-263-3) package with exposed thermal pad; tab electrically connected to OUTPUT for low-inductance heat path and simplified PCB thermal relief.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV1117-33CDR and NCP1117ST33T3G, the LD1086D2T33TR provides tighter output accuracy, lower thermal resistance in D²PAK, and superior PSRR-making it optimal for high-reliability, high-current 3.3 V rails where regulation stability and thermal performance are prioritized.

Availability

LD1086D2T33TR is available at Aetrix Electronics and suitable for industrial automation controllers, automotive body electronics, medical sensor modules, and networking infrastructure requiring stable component supply with full production lifecycle support.

Supply support for LD1086D2T33TR 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, specializing in power management, microcontrollers, and automotive ICs with broad industrial and automotive qualification coverage.

The LD1086 series targets high-current, high-precision linear regulation in space-constrained industrial and automotive applications-designed to replace legacy adjustable regulators while delivering improved accuracy, thermal performance, and ease of use.

FAQ

What is the minimum input voltage required for stable 3.3 V output at 1.5 A?

The LD1086D2T33TR requires a minimum input voltage of 4.6 V (3.3 V + 1.3 V dropout) to maintain regulation at full 1.5 A load. At lighter loads, dropout decreases-e.g., 0.8 V at 500 mA-allowing operation from lower input rails in dynamic power scenarios.

Can this regulator operate without an input bypass capacitor?

No. A minimum 1 µF ceramic capacitor placed within 5 mm of the IN pin is mandatory to prevent oscillation and ensure transient response stability. Omitting it risks high-frequency instability and potential damage during line transients, as confirmed in Figure 22–24 of the datasheet.

Is the D²PAK package lead-free and RoHS compliant?

Yes. The LD1086D2T33TR uses lead-free terminations and complies with RoHS Directive 2011/65/EU and REACH Regulation (EC) No. 1907/2006. Full material declarations and exemption status are documented in ST's official product change notices and environmental reports.

Does this part support reverse polarity protection?

No. The LD1086D2T33TR lacks built-in reverse-voltage protection. Applying negative voltage to the IN pin relative to GND may cause irreversible damage. External protection-such as a series Schottky diode or MOSFET-based ideal diode-is required in systems prone to battery reversal or hot-swap events.