STMicroelectronics LD1585CV

Overview

LD1585CV from STMicroelectronics is a 3-terminal adjustable low-dropout linear voltage regulator delivering up to 5 A output current with ±1 % output voltage tolerance at 25 °C, 1.2 V typical dropout at full load, and fast transient response optimized for low-voltage systems such as SCSI-2 active termination. It features internal thermal and power limiting, operates from 0 °C to 125 °C, and uses only a 10 µF output capacitor for stability.

For engineers reviewing the LD1585CV datasheet, LD1585CV pinout, LD1585CV application, or LD1585CV equivalent, key selection criteria include guaranteed 5 A output capability, tight ±1 % reference accuracy, dropout performance under dynamic load, thermal resistance (R_thJC = 3 °C/W), and TO-220 package compatibility with standard adjustable regulators.

Technical Context

The LD1585CV employs an NPN pass transistor architecture-unlike PNP-based regulators-so quiescent current flows into the load, improving efficiency. Its internal bandgap reference is trimmed to ±1 % at 25 °C and maintains ±2 % over 0–125 °C, enabling precise programmable output via external resistors (V_O = V_REF(1 + R2/R1)).

It achieves fast transient response through optimized loop compensation and low-output-impedance design, demonstrated in load-step tests (0.1 A → 5 A) with minimal overshoot/undershoot. Dropout voltage remains ≤1.4 V across full temperature and load range, supporting input-to-output differentials as low as 1.5 V in practical designs.

Key Specifications

Pinout & Package

Supplied in TO-220 package with exposed metal tab (electrically connected to Pin 2). Mounting requires isolation washer if heatsink is grounded. Package meets ECOPACK® environmental compliance with lead-free second-level interconnect.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM338K and LT1083CP, the LD1585CV offers superior dropout (1.4 V vs ≥2 V), tighter reference accuracy (±1 %), and integrated thermal protection-making it optimal for space-constrained, high-efficiency 5 A linear regulation where input headroom is limited.

Availability

LD1585CV is available at Aetrix Electronics and suitable for SCSI-2 termination, FPGA core power, and industrial PLC I/O modules requiring stable component supply and long-lifecycle support.

Supply support for LD1585CV 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 microcontrollers, power management ICs, analog chips, and sensors for industrial, automotive, and consumer markets.

The LD1585CV belongs to ST's high-current linear regulator product line, engineered specifically for applications demanding precision-adjustable output, fast transient immunity, and robust thermal performance in TO-220 form factor.

FAQ

What is the minimum input-to-output voltage required for stable operation at 5 A?

The LD1585CV requires a minimum input-to-output differential of 1.4 V at 5 A load to maintain regulation, per absolute maximum ratings. Below this, output voltage drops linearly with input; design margin should include 0.2 V for temperature and tolerance variation, recommending ≥1.6 V headroom in production layouts.

Can the LD1585CV be used without an output capacitor?

No. A minimum 10 µF tantalum or ceramic capacitor is mandatory at the output for stability, as confirmed in electrical characteristics and typical application diagrams. Omitting it causes oscillation and uncontrolled output voltage, risking downstream circuit damage-even at light loads.

How does the adjust pin current affect output accuracy?

The ADJ pin draws 50–100 µA (typ), and its variation (≤5 µA over load/temperature) introduces error into the resistor-divider network. To limit error to <0.1 %, use R1 ≤ 1 kΩ and R2 ≤ 10 kΩ-ensuring divider current (≥1 mA) dominates ADJ current, preserving ±1 % overall output tolerance.

Is the TO-220 tab electrically connected, and how should it be mounted?

Yes, the TO-220 metal tab is internally connected to Pin 2 (OUT). When mounting to a heatsink, use an insulating washer and shoulder washer to prevent shorting unless the heatsink is referenced to the output rail. Thermal interface material must cover the full tab area to achieve specified R_thJC = 3 °C/W.