STMicroelectronics LD1086PUR

Overview

LD1086PUR from STMicroelectronics is a 1.5 A adjustable low-dropout linear voltage regulator in DFN8 (4×4) package, delivering ±1% output voltage accuracy at 25 °C and operating across –40 °C to +125 °C. It achieves 1.3 V typical dropout at full load, requires only a 10 µF output capacitor for stability, and routes quiescent current into the load-unlike PNP-based regulators-to improve efficiency in power-constrained applications such as industrial sensor nodes and automotive body control modules.

For engineers reviewing the LD1086PUR datasheet, LD1086PUR pinout, LD1086PUR application, or LD1086PUR equivalent, key selection considerations include its adjustable output configuration (V_REF = 1.25 V), thermal shutdown and internal current limiting, compatibility with standard 3-terminal adjustable regulator layouts, and suitability for space-constrained PCBs requiring high thermal performance in DFN8 packaging.

Technical Context

The LD1086PUR implements an NPN-based pass transistor architecture with on-chip trimming for tight reference voltage tolerance (1.25 V ±1.5%). Its adjust pin draws only 40–120 µA, enabling precise external resistor-divider programming of output voltage while minimizing load-independent error contributions.

Thermal protection activates at junction temperatures exceeding 150 °C, and short-circuit current scales inversely with dropout voltage-delivering up to 2.3 A at low VI–VO differential but reducing to 50 mA at 25 V differential-ensuring safe fault handling without external current-sense circuitry.

Key Specifications

Pinout & Package

LD1086PUR is housed in a thermally enhanced DFN8 (4 mm × 4 mm, 0.75 mm height) package with exposed thermal pad. The package supports high-power dissipation (R_thJA = 33 °C/W, R_thJC = 1.5 °C/W) and requires soldering of the exposed pad to PCB ground plane for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV1117-ADJ and MCP1703T-ADJ, LD1086PUR delivers 1.5× higher output current, superior thermal resistance (1.5 °C/W vs. >50 °C/W), and tighter reference tolerance-making it the sole option among the three qualified for sustained 1.5 A operation in compact, high-ambient-temperature environments.

Availability

LD1086PUR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical patient monitor front-ends, and smart energy meter MCU subsystems requiring stable component supply with guaranteed long-term manufacturability.

Supply support for LD1086PUR 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, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.

LD1086PUR belongs to ST's high-current LDO regulator product line, engineered specifically for space-constrained, thermally demanding applications where precision, reliability, and wide input voltage range are critical-such as automotive body electronics and industrial automation.

FAQ

What is the minimum required output capacitor for LD1086PUR stability?

The LD1086PUR requires a minimum 10 µF ceramic or tantalum output capacitor for unconditional stability across all load and input conditions. Unlike many LDOs, it imposes no ESR range requirement-enabling use of low-ESR MLCCs without risk of oscillation. Larger values (e.g., 22 µF) further improve transient response but are not mandatory.

Can LD1086PUR be used in fixed-output configurations?

No-LD1086PUR is exclusively an adjustable-output variant (V_REF = 1.25 V). Fixed-output versions (e.g., LD1086V33 for 3.3 V) exist in the same family but use different part numbers and internal resistor networks. LD1086PUR requires external R1/R2 to set VO and cannot be configured as a fixed-output regulator without those components.

How does LD1086PUR handle short-circuit conditions?

Under short-circuit, LD1086PUR limits output current based on dropout voltage: ~2.3 A at 5 V differential, dropping to ~50 mA at 25 V differential. Combined with thermal shutdown (triggering at TJ ≥ 150 °C), this dual protection prevents damage without external circuitry. Recovery is automatic after fault removal and junction cooldown.

Is the exposed thermal pad on LD1086PUR's DFN8 package electrically connected?

Yes-the exposed thermal pad is internally connected to GND (Pin 8) and must be soldered to a PCB copper pour tied to system ground. This connection is essential for achieving the specified R_thJC = 1.5 °C/W and preventing thermal derating. Leaving the pad floating or unconnected violates the thermal design and risks premature thermal shutdown.