STMicroelectronics L78M24ABV

Overview

L78M24ABV from STMicroelectronics is a three-terminal positive fixed-voltage linear regulator delivering 24 V at up to 500 mA output current, with ±2 % output voltage tolerance over -40 °C to +125 °C operating junction temperature, thermal overload and short-circuit protection, and 2 V dropout voltage - used for local on-card regulation in industrial power supplies and embedded control modules.

For engineers reviewing the L78M24ABV datasheet, L78M24ABV pinout, L78M24ABV application, or L78M24ABV equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation value, and confirmed alternative options for 24 V/0.5 A fixed linear regulation.

Technical Context

The L78M24ABV employs an internal NPN pass transistor with safe-area compensation, enabling robust short-circuit survival without external current limiting. Its thermal shutdown circuit activates at junction temperatures exceeding 165 °C, and internal current limiting caps peak output at 700 mA under transient conditions.

It operates with input voltages from 27 V to 38 V (min VI–VO ≥ 2 V), supports stable regulation with only 0.33 µF input and 0.1 µF output ceramic/tantalum capacitors, and delivers 50 dB supply voltage rejection at 120 Hz across its full operating temperature range.

Key Specifications

Pinout & Package

Supplied in DPAK (TO-252) surface-mount package with exposed thermal pad for enhanced heat dissipation; R_thJA = 100 °C/W, R_thJC = 8 °C/W - requires PCB copper area ≥ 250 mm² for full 500 mA operation at ambient ≤ 60 °C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 24 V/0.5 A fixed linear regulation applications.

Compared with LM78M24CDT-TR and TL78M24CKVURG3, the L78M24ABV uniquely combines extended temperature operation, ±2 % accuracy, and documented 700 mA short-circuit peak current - making it the only choice for ruggedized industrial 24 V regulation where specification compliance is audited.

Availability

L78M24ABV is available at Aetrix Electronics and suitable for industrial automation, outdoor telecom infrastructure, and motor control systems requiring stable component supply, long-lifecycle assurance, and RoHS-compliant DPAK packaging.

Supply support for L78M24ABV 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The L78MxxA series was engineered specifically for cost-effective, robust local regulation in space-constrained industrial control boards - prioritizing thermal resilience, fault tolerance, and extended temperature compliance over ultra-low quiescent current.

FAQ

What is the minimum input voltage required for stable 24 V output?

The L78M24ABV requires a minimum input voltage of 26 V to maintain regulation, based on its 2 V dropout voltage specification at 25 °C. At full 500 mA load and elevated temperature, the dropout may increase to 2.3 V - so 26.5 V is recommended for margin in production designs.

Can L78M24ABV be used in adjustable-output configurations?

Yes - the L78M24ABV can be configured as an adjustable regulator using two external resistors, per Figure 18 in the datasheet. The output voltage range is 7.0 V to 20 V, with the constraint that V_IN – V_OUT ≥ 2.0 V. The 24 V fixed version is not internally trimmed for adjustability beyond this configuration.

Is a heatsink required for 500 mA continuous operation?

A dedicated heatsink is not required, but the DPAK package must be mounted on ≥250 mm² of 2-oz copper connected to the GND pin and thermal pad. Without this, junction temperature exceeds 125 °C at 500 mA in still air at 60 °C ambient - derating to 350 mA is necessary on minimal copper.

Does L78M24ABV support reverse-polarity input protection?

No - the L78M24ABV lacks internal reverse-voltage protection. Applying reversed input voltage will cause permanent damage. An external series Schottky diode (e.g., 1N5819) with ≤0.4 V forward drop is required if input polarity cannot be guaranteed in the system.