STMicroelectronics LD1086D2T50TR

Overview

LD1086D2T50TR from STMicroelectronics is a fixed-output 5.0 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 serves as a primary post-regulation stage in industrial power supplies and embedded control modules requiring stable 5 V rail under varying input conditions (6.6–30 V).

For engineers reviewing the LD1086D2T50TR datasheet, LD1086D2T50TR pinout, LD1086D2T50TR application, or LD1086D2T50TR equivalent, key selection criteria include dropout voltage at 1.5 A, output tolerance across –40 °C to +125 °C, minimum external capacitor requirement (10 µF), thermal resistance (R_thJC = 3 °C/W), and compatibility with standard 3-terminal adjustable regulator footprints.

Technical Context

The LD1086D2T50TR implements a PNP-based LDO architecture with on-chip trimming for tight output accuracy and a dedicated adjust pin (for adjustable variants) that draws only 40–120 µA-enabling high efficiency by routing quiescent current into the load rather than wasting it as bias. Its internal protection circuitry activates thermal shutdown at ~150 °C junction temperature and limits short-circuit current to 1.5–2.3 A depending on dropout voltage.

It operates across an input range of 6.6 V to 30 V and maintains regulation down to 1.3 V dropout at 1.5 A, with line regulation ≤10 mV and load regulation ≤35 mV over full temperature and load range-making it suitable for battery-backed systems and industrial 24 V bus derating applications where headroom is constrained.

Key Specifications

Pinout & Package

LD1086D2T50TR uses the D²PAK (SMD 2L STD-ST) package with exposed tab thermally and electrically connected to OUTPUT. The 3-pin configuration supports direct replacement of legacy TO-220 regulators in surface-mount designs while delivering superior thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LD1086V50TR, LD1086D2T50TR offers better mechanical ruggedness and standardized D²PAK tape-and-reel handling, while TLV1117-50CDR trades current capacity and thermal performance for footprint reduction-making LD1086D2T50TR optimal for industrial 1.5 A 5 V rails where reliability and thermal margin are prioritized.

Availability

LD1086D2T50TR is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control modules, medical infusion pump controllers, and point-of-sale terminal power management requiring stable component supply and long-term lifecycle support.

Supply support for LD1086D2T50TR 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-grade analog ICs with ISO/TS 16949-certified manufacturing.

The LD1086 series was designed specifically for industrial and automotive power rails demanding high current, tight tolerance, and robust thermal behavior-targeting applications where legacy PNP LDOs failed to meet efficiency or reliability requirements.

FAQ

What is the minimum input voltage required for LD1086D2T50TR to maintain 5.0 V output at 1.5 A?

The minimum input voltage is 6.6 V, derived from the 5.0 V output plus 1.3 V typical dropout voltage at 1.5 A. At lower loads, dropout decreases-e.g., ~0.8 V at 500 mA-allowing operation from as low as 5.8 V in light-load scenarios. Input below 6.6 V risks dropout and unregulated output.

Can LD1086D2T50TR replace an LM317 in an existing design?

Yes, but only in fixed-voltage configurations using the LD1086D2T50TR's preset 5.0 V output. It is pin-compatible with LM317 in TO-220 packages, but the D²PAK variant requires footprint adaptation. Unlike the LM317, it does not support adjustable output-no external resistors are used or needed.

Is an input capacitor mandatory, and what value is recommended?

A 1 µF ceramic capacitor is mandatory at the IN pin per ST's transient testing (Figures 22–24). This stabilizes response to line transients and prevents oscillation during fast input voltage steps (e.g., 12 V → 13 V). Larger values (≥4.7 µF) improve ripple rejection but are not required for basic stability.

Does LD1086D2T50TR require a heat sink in typical 1.5 A operation?

A heat sink is strongly recommended. With R_thJC = 3 °C/W and R_thCA ≈ 30–40 °C/W for a modest PCB copper area, power dissipation of (V_IN−5.0 V) × 1.5 A can exceed thermal limits-for example, at V_IN = 12 V, P_D = 10.5 W raises junction temperature by >315 °C above ambient without heatsinking. A 10 °C/W heatsink is advised for continuous 1.5 A operation.