STMicroelectronics LD1085D2M25R

Overview

LD1085D2M25R from STMicroelectronics is a fixed-output 2.5 V, 3 A low-dropout linear voltage regulator in D²PAK package, 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 delivers stable power for microcontroller core supplies, FPGA I/O rails, and industrial sensor interfaces requiring tight regulation and high current.

For engineers reviewing the LD1085D2M25R datasheet, LD1085D2M25R pinout, LD1085D2M25R application, or LD1085D2M25R equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation guidance, and confirmed alternative options with functional and packaging distinctions.

Technical Context

The LD1085D2M25R implements a PNP-based LDO architecture with on-chip trimming for ±1% initial output accuracy and integrated thermal shutdown triggered at junction temperatures exceeding +125 °C. Its reference voltage is internally set to 1.25 V, enabling precise 2.5 V output via resistor-free fixed configuration.

Unlike traditional NPN regulators, quiescent current flows into the load rather than being wasted, improving efficiency under light loads. Stability requires only a 10 µF output capacitor, and dropout remains ≤1.5 V across the full –40 °C to +125 °C operating range at 3 A output.

Key Specifications

Pinout & Package

LD1085D2M25R is supplied in the surface-mount D²PAK (TO-263) package, featuring exposed thermal pad for enhanced heat dissipation and compatibility with standard PCB reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2940CT-2.5/NOPB and TLV1117-25CDCYR, LD1085D2M25R uniquely delivers 3 A at 1.3 V dropout in surface-mount D²PAK, enabling higher power density and tighter regulation for industrial and automotive control modules where both current and thermal performance are critical.

Availability

LD1085D2M25R is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and medical diagnostic equipment requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for LD1085D2M25R 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The LD1085 series belongs to ST's high-current linear regulator product line, engineered specifically for applications demanding robust thermal performance, tight DC accuracy, and simplified fixed-voltage implementation in harsh environments.

FAQ

What is the minimum input voltage required for LD1085D2M25R to regulate at 2.5 V with 3 A load?

The minimum input voltage is calculated as VO + Vd = 2.5 V + 1.5 V (max dropout) = 4.0 V. ST specifies VI ≥ 4.1 V across full temperature and load range to guarantee regulation. Below 4.1 V, output drops linearly with input; operation below 3.8 V results in unregulated output.

Can LD1085D2M25R be used in parallel to increase output current beyond 3 A?

No-LD1085D2M25R lacks built-in current-sharing features such as current-sense pins or master-slave synchronization. Parallel operation risks thermal runaway due to mismatched dropout voltages and is not supported by ST. For >3 A, select a higher-current regulator or switch to a DC/DC solution.

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

Yes-an input capacitor is mandatory for stability and transient suppression. ST recommends ≥10 µF low-ESR tantalum or ceramic capacitor placed within 5 mm of the IN and GND pins. For high-ripple input sources (e.g., rectified AC), add a 100 µF bulk electrolytic upstream to limit voltage sag during load steps.

Does LD1085D2M25R include reverse-polarity protection?

No-LD1085D2M25R has no internal reverse-voltage protection. Applying negative voltage to IN relative to GND can damage the IC. In battery-powered systems with potential polarity reversal, add an external series Schottky diode (e.g., 1N5822) or ideal diode controller on the input rail.