STMicroelectronics LD1086V25

Overview

LD1086V25 from STMicroelectronics is a fixed-output 2.5 V, 1.5 A low-dropout linear voltage regulator in TO-220 and surface-mount packages. It delivers ±1% output tolerance at 25 °C, 1.3 V typical dropout at full load, and operates across –40 °C to +125 °C. Used for post-regulation in industrial power supplies, FPGA core rails, and embedded microcontroller subsystems requiring stable low-noise DC.

For engineers reviewing the LD1086V25 datasheet, LD1086V25 pinout, LD1086V25 application, or LD1086V25 equivalent, key selection criteria include dropout voltage at 1.5 A, thermal resistance (R_thJA = 50 °C/W in TO-220), output tolerance over temperature, minimum load current (3–10 mA), and adjust-pin current stability (40–120 µA) in adjustable configurations.

Technical Context

The LD1086V25 integrates an internal bandgap reference (1.25 V), error amplifier, and NPN pass transistor with on-chip trimming for ±1% initial accuracy. Its quiescent current flows into the load-not wasted as bias-improving efficiency versus PNP-based regulators. Dropout behavior is monotonic and guaranteed ≤1.5 V at 1.5 A across temperature.

Stability requires only a 10 µF output capacitor (tantalum or ceramic); no ESR constraints apply. Internal thermal shutdown and current limiting protect against overload and fault conditions. The device supports both fixed-output (e.g., V25 = 2.5 V) and adjustable modes via external resistor divider on the ADJ pin.

Key Specifications

Pinout & Package

LD1086V25 is available in TO-220 (3-pin, tab-connected to OUTPUT), DPAK, D²PAK, D²PAK/A, and DFN8 (4×4 mm) packages. Pin functions are identical across variants: Pin 1 = INPUT, Pin 2 = OUTPUT (tab-connected), Pin 3 = GND (TO-220/DPAK) or ADJ (adjustable versions). LD1086V25 is fixed-output; its third pin is GND, not ADJ.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV1117-25 and TPS7A4701RGWR, LD1086V25 uniquely balances 1.5 A delivery, 1.3 V dropout, ±1% tolerance, and TO-220 thermal robustness - making it optimal for industrial and automotive power rails where reliability and current headroom outweigh ultra-low-noise requirements.

Availability

LD1086V25 is available at Aetrix Electronics and suitable for industrial PLCs, FPGA power systems, medical sensor modules, and automotive body control units requiring stable component supply with extended temperature support and long-lifecycle assurance.

Supply support for LD1086V25 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The LD1086 series was developed to replace legacy PNP-based regulators with higher-efficiency NPN architecture, targeting cost-sensitive yet thermally demanding applications in factory automation and transportation electronics.

FAQ

What is the minimum input voltage required for LD1086V25 to regulate 2.5 V at 1.5 A?

The minimum input voltage is calculated as V_OUT + V_DROP(max) = 2.5 V + 1.5 V = 4.0 V. ST specifies guaranteed regulation down to 4.1 V input across temperature and load, accounting for worst-case dropout and line/load regulation. Below 4.1 V, output drops linearly with input.

Can LD1086V25 be used in adjustable mode?

No - LD1086V25 is a fixed-output variant with internal resistor divider setting 2.5 V. Adjustable versions (e.g., LD1086D2M) use the ADJ pin and external resistors. Using LD1086V25 in adjustable circuits risks incorrect output voltage or instability due to missing ADJ functionality.

Is a heat sink required for LD1086V25 in TO-220 package at 1.5 A?

Yes - at 1.5 A with 12 V input, power dissipation is (12 − 2.5) × 1.5 ≈ 14.25 W. With R_thJA = 50 °C/W, junction rise would exceed 700 °C without heatsinking. A 5–10 °C/W heatsink plus thermal interface is mandatory for continuous 1.5 A operation at ambient >25 °C.

Does LD1086V25 require an input capacitor?

While not strictly mandatory for stability, ST recommends ≥1 µF ceramic capacitor at the IN pin, placed within 5 mm of the package. This suppresses high-frequency noise from upstream sources and prevents oscillation during fast line transients - especially critical when fed from switchers or long PCB traces.