STMicroelectronics L78M05CV-DG

Overview

L78M05CV-DG from STMicroelectronics is a three-terminal positive fixed-voltage linear regulator delivering 5 V ±2 % output at up to 0.5 A, housed in a TO-220FP package with thermal overload, short-circuit, and safe operating area protection. It operates across 0 to 125 °C junction temperature and supports local on-card regulation in industrial power supplies, microcontroller power rails, and sensor interface circuits.

For engineers reviewing the L78M05CV-DG datasheet, L78M05CV-DG pinout, L78M05CV-DG application, or L78M05CV-DG equivalent, key selection criteria include output voltage tolerance (±2 %), dropout voltage (2 V), quiescent current (6 mA), supply voltage rejection (62 dB at 120 Hz), and thermal resistance junction-to-case (5 °C/W) for heatsink-limited designs.

Technical Context

The L78M05CV-DG implements a monolithic series pass transistor with internal current limiting, thermal shutdown, and SOA compensation-ensuring robustness under sustained overload or ambient temperature extremes. Its architecture requires no external compensation for stability but benefits from a 0.33 µF input bypass capacitor when located >10 cm from the bulk filter.

It functions as a standalone fixed-output regulator but supports adjustable configurations via external resistors (e.g., voltage boosting, constant-current sourcing, or tracking regulators), leveraging its uncommitted pass transistor base-emitter node per Figure 18–24 of DS0425 Rev 24.

Key Specifications

Pinout & Package

TO-220FP (Full-Pak) package: vertical mounting, insulated tab, 3-pin through-hole configuration with integrated heatsink pad. Pin 1 = Input, Pin 2 = Ground, Pin 3 = Output - verified per Figure 2 (DS0425 Rev 24, page 3/45).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78M05CDT-TR and MC78M05BDTG, the L78M05CV-DG offers superior thermal performance (5 °C/W vs 8 °C/W) and tighter output accuracy (±2 % vs ±4 %), making it optimal for thermally demanding or precision-regulated 5 V applications where through-hole mounting is acceptable.

Availability

L78M05CV-DG is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control modules, medical patient monitors, and point-of-sale terminals requiring stable component supply with long lifecycle visibility.

Supply support for L78M05CV-DG 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, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The L78M series belongs to ST's precision 500 mA linear regulator product line, engineered for robust local regulation in harsh environments where thermal resilience, fault tolerance, and consistent DC accuracy are critical.

FAQ

What is the maximum input voltage for L78M05CV-DG?

The absolute maximum DC input voltage is 35 V for 5 V output variants. Exceeding this risks permanent damage even if thermal protection activates. For reliable operation, keep input below 30 V with adequate heatsinking-especially at high ambient temperatures or near maximum load current.

Does L78M05CV-DG require input and output capacitors?

Yes: a 0.33 µF input capacitor (tantalum or ceramic) is mandatory when the regulator is >10 cm from the bulk filter to prevent oscillation; a 0.1 µF output capacitor improves load transient response. Neither is needed for basic stability, but both are specified in ST's application circuit (Figure 4, DS0425).

Can L78M05CV-DG be used in adjustable configurations?

Yes-its internal topology allows external resistor networks to configure adjustable output voltages (7–30 V), constant-current sources, or tracking regulators, as shown in Figures 18–24 of DS0425. The base-emitter node of the pass transistor is accessible internally, enabling these extensions without compromising protection features.

How does thermal protection behave under sustained overload?

When junction temperature exceeds ~160 °C, thermal shutdown disables the output until temperature falls by ~20 °C. Recovery is automatic and non-latching. During repeated cycling, average output current drops significantly-designers must size heatsinks to maintain T_J < 125 °C at worst-case load and ambient to avoid functional interruption.