STMicroelectronics LD1585CV50

Overview

LD1585CV50 from STMicroelectronics is a 5 A low-dropout adjustable positive voltage regulator in TO-220 package, featuring ±1 % output voltage tolerance at 25 °C, 1.2 V typical dropout at full load, and fast transient response optimized for low-voltage systems. It delivers stable 5.0 V output (via external resistor divider), supports 0–125 °C operating junction temperature, and is used in SCSI-2 active termination and industrial power rails.

For engineers reviewing the LD1585CV50 datasheet, LD1585CV50 pinout, LD1585CV50 application, or LD1585CV50 equivalent, key selection criteria include guaranteed 5 A output current, internal thermal/power limiting, 10 µF minimum output capacitance for stability, adjust pin current ≤100 µA, and ±2 % output tolerance across full temperature range.

Technical Context

The LD1585CV50 employs an NPN-based pass transistor architecture-unlike PNP regulators-so quiescent current flows into the load, improving efficiency. Its reference voltage is trimmed on-chip to 1.25 V (±1 %), enabling precise 5.0 V output via R1/R2 feedback network with VO = 1.25(1 + R2/R1).

It achieves fast load transient response (<10 µs recovery) due to high gain error amplifier and low output impedance, and integrates internal short-circuit protection with 5.5–7 A current limit and thermal shutdown triggered at TJ ≥150 °C.

Key Specifications

Pinout & Package

Supplied in TO-220 package with exposed metal tab (electrically connected to pin 2), offering mechanical robustness and thermal performance suitable for conduction-cooled PCB mounting.

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 LD1585CV50 offers superior thermal protection integration, faster transient response, and better efficiency via NPN architecture-making it optimal for space-constrained industrial power rails where reliability and dynamic load handling are prioritized over absolute lowest quiescent current.

Availability

LD1585CV50 is available at Aetrix Electronics and suitable for SCSI-2 termination circuits, industrial PLC I/O power rails, and test equipment power supplies requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for LD1585CV50 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 microcontrollers, power management ICs, sensors, and discrete components for industrial, automotive, and consumer markets.

The LD1585C series targets high-current, low-dropout linear regulation in industrial and computing infrastructure-emphasizing thermal robustness, fast transient immunity, and precision output voltage control without external compensation.

FAQ

What is the minimum input voltage required for LD1585CV50 to regulate 5.0 V output?

The minimum input voltage is determined by dropout: VI(min) = VO + Vd. With 1.2 V typical dropout at 5 A, VI must be ≥6.2 V. At lighter loads, dropout decreases-e.g., ~0.5 V at 1 A-allowing VI as low as 5.5 V while maintaining regulation. Always verify margin against worst-case 1.4 V max dropout per datasheet.

Can LD1585CV50 be used without an output capacitor?

No. A minimum 10 µF tantalum or ceramic output capacitor is mandatory for stability per datasheet Section 4 and Figure 3. Omitting it causes oscillation and potential device failure. The capacitor also improves transient response and reduces output ripple; values >10 µF further enhance load-step immunity.

How does the ADJ pin current affect output voltage accuracy?

ADJ pin current (50–100 µA) flows through the R2 resistor in the feedback divider, creating an offset error in the sensed voltage. To limit this error to <0.1 %, R2 should be ≤1.2 kΩ for 5.0 V output. Higher R2 values increase error; lower values increase divider power loss-designers must balance accuracy, power, and noise.

Is LD1585CV50 suitable for automotive applications?

No. LD1585CV50 is not qualified to AEC-Q100 and lacks automotive-specific stress testing, extended temperature validation beyond 125 °C junction, or guaranteed operation under load-dump or cold-crank conditions. ST recommends automotive-grade alternatives like LDO45xx series for vehicle ECUs or infotainment systems.