STMicroelectronics LD1085D2M12R

Overview

LD1085D2M12R from STMicroelectronics is a fixed-output 1.2 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 FPGA core rails, microcontroller I/O banks, and industrial PLC logic supplies where precision and thermal robustness are critical.

For engineers reviewing the LD1085D2M12R datasheet, LD1085D2M12R pinout, LD1085D2M12R application, or LD1085D2M12R 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 documented functional differences.

Technical Context

The LD1085D2M12R uses an NPN-based pass transistor architecture that routes quiescent current into the load-unlike PNP regulators-improving efficiency and reducing wasted bias current. Its reference voltage is trimmed on-chip to 1.25 V ±1%, enabling tight output accuracy without external calibration.

It operates as a three-terminal fixed-output regulator with no external feedback resistors required; stability is ensured with only a 10 µF output capacitor. Dropout voltage remains ≤1.5 V across –40 °C to +125 °C junction temperature and up to 3 A load, supported by internal thermal shutdown and short-circuit protection.

Key Specifications

Pinout & Package

LD1085D2M12R is housed in a surface-mount D²PAK (TO-263) package with exposed thermal pad for enhanced heat dissipation. The package measures 10.4 mm × 9.35 mm × 4.6 mm and is RoHS-compliant per ST's ECOPACK® standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV1117-12CDR and NCP1117DT12RKG, LD1085D2M12R uniquely supports 3 A at ±1% accuracy with 1.3 V dropout in D²PAK, making it the only option among the three qualified for high-current, thermally demanding 1.2 V core supplies.

Availability

LD1085D2M12R is available at Aetrix Electronics and suitable for industrial automation systems, motor control inverters, and medical diagnostic equipment requiring stable component supply with guaranteed long-term manufacturability and traceable sourcing.

Supply support for LD1085D2M12R 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 power management applications.

LD1085D2M12R belongs to ST's LD1085 low-dropout regulator family, engineered specifically for high-current, thermally constrained industrial and embedded power systems requiring precision voltage regulation without external feedback components.

FAQ

Is LD1085D2M12R pin-compatible with adjustable versions of the LD1085?

Yes-LD1085D2M12R uses the same three-terminal D²PAK pinout (IN, OUT, GND) as adjustable LD1085 variants. No layout change is needed when upgrading from adjustable to fixed 1.2 V output, though external feedback resistors must be removed and the ADJ pin left unconnected or tied to OUT per datasheet guidance.

What is the minimum input voltage required for regulation at 3 A load?

The minimum input voltage is 2.5 V: with 1.3 V typical dropout at 3 A and a nominal 1.2 V output, VI(min) = VO + Vd = 1.2 V + 1.3 V = 2.5 V. At higher temperatures or worst-case tolerance, plan for up to 2.7 V input to maintain regulation across full operating range.

Can LD1085D2M12R be paralleled for higher current?

No-LD1085D2M12R lacks built-in current-sharing features such as current-sense outputs or master-slave synchronization. Paralleling risks thermal runaway due to mismatched dropout voltages; ST recommends using a single higher-current regulator or discrete MOSFET-based solutions instead.

Does LD1085D2M12R require an input capacitor?

Yes-an input capacitor of ≥1 µF ceramic is required for stability and high-frequency noise suppression. ST specifies 1 µF minimum at the IN pin; larger values (e.g., 4.7–10 µF) improve transient response and reduce ripple coupling from upstream switching stages.