STMicroelectronics L78M24CV

Overview

L78M24CV from STMicroelectronics is a three-terminal positive fixed-voltage linear regulator delivering 24 V at up to 500 mA output current in TO-220FP package, featuring thermal overload protection, short-circuit protection, and safe operating area (SOA) compensation for robust local on-card regulation in industrial power supplies and embedded systems.

For engineers reviewing the L78M24CV datasheet, L78M24CV pinout, L78M24CV application, or L78M24CV equivalent, key selection considerations include its ±2 % output voltage tolerance (C version), 2 V dropout voltage at 350 mA, 50 dB supply voltage rejection at 120 Hz, 170 µV output noise (10 Hz–100 kHz), and operation across 0 °C to 150 °C junction temperature range.

Technical Context

The L78M24CV implements a monolithic series-pass transistor architecture with internal current limiting, thermal shutdown, and SOA protection-enabling self-protecting operation without external components under fault conditions. Its fixed 24 V output is trimmed during manufacturing to meet ±2 % tolerance over temperature and load.

It operates with a minimum input-to-output differential of 2 V and supports input voltages up to 40 V (for 24 V output), maintaining regulation across IO = 5–500 mA and TJ = 0–150 °C. Quiescent current remains stable at 6 mA with <0.8 mA variation over full line/load/temperature range.

Key Specifications

Pinout & Package

Supplied in TO-220FP (Full Pack) package: insulated case, vertical mounting, 3-pin through-hole configuration with integrated heat sink tab. Thermal resistance: R_thJC = 5 °C/W, R_thJA = 60 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78M24CDT and MC78M24CD2TR4G, the L78M24CV offers superior thermal performance (R_thJA = 60 °C/W vs. 100 °C/W), tighter initial tolerance, and ECOPACK2 compliance-making it optimal for thermally constrained, high-reliability industrial applications requiring long-term supply continuity.

Availability

L78M24CV is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, and test & measurement equipment requiring stable component supply, long-lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for L78M24CV 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, specializing in power management, microcontrollers, and analog ICs 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 reliability, thermal resilience, and long-term availability are critical.

FAQ

What is the maximum allowable input voltage for L78M24CV?

The absolute maximum DC input voltage is 40 V for VO = 24 V, as specified in Table 1 of DS0425 Rev 24. Operation above this level risks permanent damage even with thermal protection active. For reliable long-term use, keep VI ≤ 38 V under full load and ambient temperatures up to 70 °C.

Does L78M24CV require input and output capacitors?

Yes-an input bypass capacitor ≥0.33 µF (tantalum or ceramic) is mandatory when the regulator is located >2 cm from the bulk filter, and an output capacitor ≥0.1 µF is recommended to improve transient response. Neither is required for basic stability, but omission degrades line/load regulation and noise performance.

How does thermal protection behave during sustained overload?

When junction temperature exceeds ~150 °C, the internal thermal shutdown circuit disables the pass transistor until temperature falls by ~20 °C. This cycle repeats autonomously-no latch-up occurs. Recovery time depends on heatsink mass and airflow; typical duty cycle under 100 % short-circuit is <10 %.

Can L78M24CV be used in adjustable configurations?

Yes-per Figure 19 and 20 in DS0425, it can serve as a stable reference in adjustable topologies (e.g., VO = 24 V × (1 + R2/R1) + I_dR2). However, output accuracy and regulation degrade due to added resistor tolerances and quiescent current dependency; fixed-mode operation delivers best-in-class 2 % tolerance.