STMicroelectronics L78M12CV-DG

Overview

L78M12CV-DG from STMicroelectronics is a three-terminal positive fixed-voltage linear regulator delivering 12 V ±2 % (AB-grade tolerance), 500 mA output current, with thermal overload, short-circuit, and safe operating area (SOA) protection. It operates across -40 °C to 125 °C junction temperature and is used for local on-card regulation in industrial power supplies, embedded control modules, and sensor interface circuits.

For engineers reviewing the L78M12CV-DG datasheet, L78M12CV-DG pinout, L78M12CV-DG application, or L78M12CV-DG equivalent, key selection criteria include guaranteed 12 V output accuracy, 2 V dropout voltage at 350 mA, 55 dB supply voltage rejection at 120 Hz, 75 µV output noise (10 Hz–100 kHz), and TO-220FP package thermal resistance of 5 °C/W junction-to-case.

Technical Context

This device implements a monolithic series pass transistor with internal current limiting, thermal shutdown, and SOA compensation-ensuring robust operation under sustained overload or fault conditions. Its architecture requires no external compensation for stability, though input bypassing with ≥0.33 µF capacitor is recommended when wiring inductance exceeds 10 cm.

The regulator maintains regulation over input voltages from 14.5 V to 30 V (VI ≥ VO + 2 V), supports load currents up to 500 mA with adequate heatsinking, and exhibits -1 mV/°C output voltage drift over 0–125 °C for the C-grade variant-confirmed in Table 12 of DS0425 Rev 24.

Key Specifications

Pinout & Package

Supplied in TO-220FP (IPAK) package: 3-pin, vertical mounting, insulated tab, 5 °C/W R_thJC, compatible with standard TO-220 heatsinks using M3 screw.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78M12CDT-TR and MC78M12BDTG, L78M12CV-DG offers tighter output tolerance, lower junction-to-case thermal resistance, and optimized TO-220FP packaging-making it preferred for thermally demanding, accuracy-critical embedded systems.

Availability

L78M12CV-DG is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and medical instrumentation requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for L78M12CV-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 silicon solutions for automotive, industrial, and consumer markets since 1987.

L78M12CV-DG belongs to the L78M Precision 500 mA regulator family-engineered for robust local regulation in harsh environments where reliability, thermal resilience, and tight DC accuracy are essential.

FAQ

What is the maximum input voltage for L78M12CV-DG?

The absolute maximum DC input voltage is 35 V for output voltages between 5 V and 18 V, as specified in Table 1 of DS0425 Rev 24. For L78M12CV-DG (12 V output), this limit applies directly. Operation above 30 V is not recommended for continuous use due to excessive power dissipation and thermal stress-even with heatsinking.

Does L78M12CV-DG require an input capacitor?

Yes-an input bypass capacitor of at least 0.33 µF (tantalum, ceramic, or film) is required when the regulator is located more than 10 cm from the main power supply filter, per Section 7.1 of DS0425. This prevents oscillation and improves transient response by lowering source impedance at high frequencies.

Can L78M12CV-DG be used in adjustable configurations?

Yes-though designed as a fixed 12 V regulator, it can be configured as an adjustable regulator using external resistors and transistors, as shown in Figures 19–24 of DS0425. Common implementations include voltage boosting, constant-current sources, and high-current extensions-but accuracy and thermal limits must be recalculated for each topology.

What is the difference between L78M12CV-DG and L78M12CDT?

L78M12CV-DG uses TO-220FP (IPAK) packaging with insulated tab and 5 °C/W R_thJC, while L78M12CDT uses standard TO-220 with non-insulated tab and 6.5 °C/W R_thJC. Both are AB-grade (±2 %), but the V-DG variant offers superior thermal performance and electrical isolation-critical for grounded heatsink applications.