STMicroelectronics LD1086V50

Overview

LD1086V50 from STMicroelectronics is a fixed-output 5.0 V, 1.5 A low-dropout linear voltage regulator in TO-220 and surface-mount packages. It delivers ±1% output tolerance at 25 °C, maintains regulation down to 1.3 V dropout at full load, and operates across –40 °C to +125 °C for industrial power rails and embedded system supplies.

For engineers reviewing the LD1086V50 datasheet, LD1086V50 pinout, LD1086V50 application, or LD1086V50 equivalent, this page provides verified pin functions, thermal performance data, stability requirements (10 µF min. output capacitor), and validated alternatives for fixed 5 V supply design in space-constrained or thermally demanding environments.

Technical Context

The LD1086V50 integrates an internal bandgap reference (1.25 V), error amplifier, and PNP pass transistor with current-limited output stage. Its quiescent current flows into the load-not wasted as bias-improving efficiency over legacy regulators. Dropout voltage remains stable across temperature and load due to on-chip trimming and thermal foldback protection.

It supports both fixed-output (V50 variant) and adjustable configurations via the ADJ/GND pin. In fixed mode, the ADJ/GND terminal is internally connected to ground, eliminating external resistor networks while retaining compatibility with standard 3-terminal regulator footprints and PCB layouts.

Key Specifications

Pinout & Package

LD1086V50 is available in TO-220 (3-pin, tab-connected to OUTPUT), DPAK (3-pin), D²PAK (3-pin), D²PAK/A (3-pin), and DFN8 (4×4 mm, 8-pin). The TO-220 package uses standard heatsink mounting; DFN8 requires exposed pad soldering for optimal thermal performance (R_thJA = 33 °C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed 5 V LDO applications.

Compared with LD1086V50, LD1086D50TR offers superior thermal resistance in surface-mount form, while TLV1117-50 trades current capability and precision for lower unit cost - making LD1086V50 optimal for robust 1.5 A industrial 5 V rails where accuracy and thermal margin are non-negotiable.

Availability

LD1086V50 is available at Aetrix Electronics and suitable for industrial automation power supplies, automotive body electronics, medical diagnostics equipment, and networking infrastructure requiring stable component supply and long-term manufacturability.

Supply support for LD1086V50 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 specifically for applications demanding tight voltage accuracy, low dropout, and rugged thermal behavior in harsh environments - not general-purpose replacement but mission-critical power integrity.

FAQ

What is the minimum input voltage required for LD1086V50 to maintain 5 V output at 1.5 A?

The minimum input voltage is 6.3 V, calculated as 5.0 V + 1.3 V typical dropout. At full load and elevated temperature, dropout may reach 1.5 V, so 6.5 V is recommended for design margin. Input below 6.3 V causes output to drop out of regulation, with no reverse current protection.

Can LD1086V50 be used in parallel to increase output current?

No - LD1086V50 lacks built-in current-sharing features such as current-sense outputs or master-slave control. Parallel connection risks thermal runaway due to mismatched dropout voltages and is not supported by STMicroelectronics. For >1.5 A, use a single higher-current regulator or switch-mode solution.

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

Yes - a minimum 1 µF ceramic or tantalum capacitor is required at the IN pin, placed within 5 mm of the device. This stabilizes the input impedance, suppresses high-frequency noise from upstream sources, and prevents oscillation during fast load transients. Larger values (e.g., 10 µF) improve line transient response.

Does LD1086V50 require a minimum load current to maintain regulation?

No - unlike some older LDOs, LD1086V50 has no minimum load requirement. It regulates stably from zero load up to 1.5 A. This is confirmed in Table 7 (LD1086B#) where IO(min) = 3–10 mA applies only to adjustable variants using the ADJ pin; the fixed V50 version operates down to 0 mA.