STMicroelectronics LD1086BDTTR

Overview

LD1086BDTTR from STMicroelectronics is a 1.5 A adjustable low-dropout linear voltage regulator with ±1% output voltage tolerance at 25 °C, 1.3 V typical dropout at full load, and internal thermal/overcurrent protection. It operates from −40 °C to +125 °C and requires only a 10 µF output capacitor for stability. It serves as a precision post-regulator in industrial power supplies and embedded system rails.

For engineers reviewing the LD1086BDTTR datasheet, LD1086BDTTR pinout, LD1086BDTTR application, or LD1086BDTTR equivalent, key selection criteria include dropout voltage under 1.5 A load, adjust-pin current stability (40–120 µA), reference voltage accuracy (1.25 V ±1.5%), thermal regulation (0.01–0.04 %/W), and compatibility with DPAK package layout constraints.

Technical Context

The LD1086BDTTR implements an NPN-based LDO architecture with an internal 1.25 V bandgap reference and error amplifier driving a PNP pass transistor. Its adjust pin senses feedback via external resistors, enabling programmable output from 1.25 V to 27 V. Dropout behavior is monotonic and specified down to 1.3 V at 1.5 A - critical for 3.3 V or 5 V systems powered from marginal input rails.

Quiescent current flows entirely into the load (not ground), improving efficiency over legacy PNP regulators. Internal thermal shutdown activates at ~150 °C junction temperature, and short-circuit current is foldback-limited to 1.5–2.3 A depending on dropout voltage - ensuring safe operation during fault conditions without external current sensing.

Key Specifications

Pinout & Package

LD1086BDTTR uses the DPAK (TO-252) surface-mount package with exposed thermal pad. The tab is electrically connected to the OUTPUT pin, requiring appropriate PCB copper pour for thermal management and electrical isolation from ground planes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM317LDR2G and TLV1117-33CDR, LD1086BDTTR uniquely delivers 1.5 A adjustability with 1.3 V dropout and ±1% accuracy - making it the only option among the three capable of powering high-current digital loads while maintaining tight regulation across automotive and industrial temperature ranges.

Availability

LD1086BDTTR is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control units, medical patient monitors, and PoE-powered networking equipment requiring stable component supply and long-term manufacturability.

Supply support for LD1086BDTTR 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.

LD1086BDTTR belongs to ST's high-current LDO regulator product line, engineered specifically for robust, thermally efficient post-regulation in harsh-environment applications where reliability and precision outweigh ultra-low IQ requirements.

FAQ

What is the minimum load current required for stable operation of LD1086BDTTR?

The LD1086BDTTR specifies a minimum load current of 3–10 mA (depending on input voltage), verified across −40 °C to +125 °C. This ensures proper biasing of internal circuitry and prevents output voltage overshoot during light-load transients. For zero-load applications, a 1–2 mA bleed resistor is recommended.

Can LD1086BDTTR be used in parallel to increase output current?

No - LD1086BDTTR is not designed for parallel operation. Its output voltage tolerance (±1% at 25 °C) and load regulation (up to 35 mV) make current sharing unstable without external ballasting resistors or active current-sharing circuitry, which degrade efficiency and accuracy. Use a single higher-current regulator instead.

Is the thermal pad of the DPAK package electrically connected, and how should it be handled on the PCB?

Yes - the exposed thermal pad on the LD1086BDTTR DPAK package is internally connected to the OUTPUT pin. It must be soldered to a dedicated output-copper pour (not ground) and thermally isolated from adjacent nets. ST recommends a 6×6 mm thermal pad with 4–9 thermal vias to inner ground planes for heat dissipation.

Does LD1086BDTTR support ceramic output capacitors, and what ESR range is acceptable?

Yes - LD1086BDTTR is stable with ceramic output capacitors ≥10 µF, including low-ESR types. The datasheet confirms stability down to 5 mΩ ESR (typical for X5R/X7R ceramics). No series ESR is required, unlike older LDOs - simplifying design and reducing board area.