STMicroelectronics LD1086D2TTR

Overview

LD1086D2TTR 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 supports input voltages up to 30 V, 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 LD1086D2TTR datasheet, LD1086D2TTR pinout, LD1086D2TTR application, or LD1086D2TTR equivalent, key selection criteria include dropout performance at 1.5 A, adjust-pin current (40–120 µA), thermal regulation (0.01–0.04 %/W), and compatibility with standard 3-terminal adjustable regulator layouts.

Technical Context

The LD1086D2TTR uses an NPN-based pass transistor architecture with internal bandgap reference and error amplifier, enabling high PSRR (up to 88 dB) and tight line/load regulation (≤0.2 %). Its adjust pin draws low, stable current (40–120 µA), allowing precise external resistor-divider programming of output voltage via VO = VREF × (1 + R1/R2), where VREF = 1.25 V.

Thermal protection activates at junction temperatures exceeding 150 °C, and internal current limiting ensures safe short-circuit operation. Unlike PNP regulators, quiescent current flows into the load-not wasted-improving efficiency under light loads.

Key Specifications

Pinout & Package

LD1086D2TTR is housed in a surface-mount D²PAK (SMD 3L STD-ST) package with exposed thermal pad. The tab is electrically connected to the OUTPUT pin, requiring appropriate PCB copper pour for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM317LDR2G and TLV1117LV33DCYR, LD1086D2TTR delivers 1.5× higher current, 300 mV lower dropout, tighter tolerance, and integrated thermal/current protection-making it the sole viable option for high-reliability, high-current adjustable LDO use cases.

Availability

LD1086D2TTR is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, medical diagnostics, and networking edge devices requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for LD1086D2TTR 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.

LD1086D2TTR belongs to ST's high-current LDO regulator product line, engineered for robustness in harsh environments and designed to replace legacy PNP-based regulators with superior efficiency, accuracy, and thermal behavior.

FAQ

What is the minimum required output capacitor for stability?

The LD1086D2TTR requires a minimum 10 µF output capacitor with low ESR (e.g., ceramic or tantalum) for guaranteed stability across all operating conditions. Using less capacitance risks oscillation, especially under transient load changes. ST recommends 22 µF for improved transient response in high-dynamic applications like microcontroller wake-up events.

Can LD1086D2TTR be used in parallel for higher current?

No-LD1086D2TTR is not designed for parallel operation. Its adjust-pin architecture and lack of current-sharing control make paralleling unsafe and unstable. For >1.5 A, select a higher-current LDO (e.g., LD1085) or use a switching regulator stage followed by local LDOs per subsystem.

Is the D²PAK thermal pad electrically isolated?

No-the D²PAK tab (pin 2) is internally connected to the OUTPUT terminal. It must be soldered to a PCB copper pour tied to the output net, not ground. This connection provides both electrical output conduction and primary thermal path; isolation would compromise thermal performance and violate device construction.

Does LD1086D2TTR support reverse polarity protection?

No-LD1086D2TTR has no built-in reverse-polarity protection. Applying reversed input voltage will cause destructive current flow through the internal substrate diode. External protection (e.g., series Schottky diode or ideal diode controller) is mandatory in systems where input reversal is possible.