STMicroelectronics LD1086D2M

Overview

LD1086D2M from STMicroelectronics is a 1.5 A adjustable low-dropout linear voltage regulator in D²PAK package, delivering ±1% output voltage tolerance at 25 °C and dropout as low as 1.3 V at full load. It features internal thermal and power limiting, operates from –40 °C to +125 °C, and requires only a 10 µF output capacitor for stability-used in industrial power rails and embedded system core supplies.

For engineers reviewing the LD1086D2M datasheet, LD1086D2M pinout, LD1086D2M application, or LD1086D2M equivalent, key selection criteria include dropout voltage at 1.5 A, adjust-pin current (40–120 µA), thermal resistance (R_thJC = 3 °C/W), minimum load requirement (3–10 mA), and compatibility with standard 3-terminal adjustable regulator layouts.

Technical Context

The LD1086D2M implements an NPN-based LDO architecture with an internal 1.25 V reference and external resistor divider on the ADJ pin to set output voltage. Its quiescent current flows into the load-not wasted as base current-improving efficiency over legacy PNP regulators.

It integrates thermal shutdown and short-circuit protection with foldback current limiting. Dropout voltage remains stable across temperature (–40 °C to +125 °C) and load (0–1.5 A), and supply voltage rejection exceeds 60 dB at 120 Hz with 25 µF output capacitance.

Key Specifications

Pinout & Package

D²PAK (SMD 3L STD-ST) package: thermally enhanced surface-mount outline with exposed tab electrically connected to OUTPUT pin; suitable for automated assembly and high-power density designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable LDO regulator applications.

Compared with LM317T and TLV1117-33, LD1086D2M delivers superior thermal capability (R_thJC = 3 °C/W), tighter output accuracy, and load-referred quiescent current-making it optimal for high-current, wide-temperature, or efficiency-critical LDO roles where adjustability is required.

Availability

LD1086D2M is available at Aetrix Electronics and suitable for industrial automation controllers, automotive body electronics, medical diagnostic equipment, and networking infrastructure requiring stable component supply and long-term manufacturability.

Supply support for LD1086D2M 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, designing and manufacturing analog, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.

The LD1086 series belongs to ST's high-current linear regulator product line, engineered for robustness in harsh environments and designed to replace legacy adjustable regulators while improving efficiency, accuracy, and thermal performance.

FAQ

What is the minimum load current required for stable operation of LD1086D2M?

The LD1086D2M requires a minimum load current of 3–10 mA depending on input voltage (higher VI demands higher I_MIN). This ensures proper biasing of internal circuitry and prevents output voltage drift or oscillation-especially critical in no-load standby modes. A 1 kΩ pull-down resistor from OUTPUT to GND satisfies this requirement in most applications.

Can LD1086D2M be used in parallel for higher current output?

No-LD1086D2M is not designed for parallel operation. Its output voltage tolerance (±1% to ±2%) and load regulation (up to 35 mV) cause current imbalance between units, risking thermal runaway. For >1.5 A, select a single higher-current regulator (e.g., LD1085) or use a switching pre-regulator followed by LD1086D2M for low-noise post-regulation.

Is the D²PAK tab electrically isolated from the output pin?

No-the metal tab of the LD1086D2M D²PAK package is internally bonded to the OUTPUT pin. It must be electrically connected to the output net on the PCB and thermally coupled to a copper pour or heatsink. If isolation from the output is required, use insulating thermal pads or consider the DFN8 variant (where tab is GND-connected).

How does the adjust pin current affect output voltage accuracy?

The ADJ pin draws 40–120 µA, which flows through the lower resistor (R2) of the feedback divider. This introduces a systematic error: V_OUT = 1.25 × (1 + R1/R2) + I_ADJ × R2. To maintain ±1% accuracy, R2 should be ≤ 1 kΩ (e.g., R2 = 1.2 kΩ, R1 = 3.92 kΩ for 5.0 V), limiting divider current to minimize error and self-heating.