STMicroelectronics L78M24ABDT-TR

Overview

L78M24ABDT-TR from STMicroelectronics is a fixed-output +24 V, 500 mA positive linear voltage regulator in DPAK package, featuring ±2 % output voltage tolerance, thermal overload protection, short-circuit protection, and safe operating area (SOA) protection. It delivers stable local regulation for industrial power rails, motor control logic supplies, and analog sensor biasing where input-to-output differential up to 14 V is typical.

For engineers reviewing the L78M24ABDT-TR datasheet, L78M24ABDT-TR pinout, L78M24ABDT-TR application, or L78M24ABDT-TR equivalent, key selection criteria include guaranteed -40 °C to +125 °C operation, 2 V dropout voltage at 350 mA, 50 dB supply voltage rejection at 120 Hz, 170 µV output noise (10 Hz–100 kHz), and DPAK thermal resistance of 8 °C/W junction-to-case.

Technical Context

This three-terminal monolithic regulator uses an internal NPN pass transistor with built-in current limiting, thermal shutdown, and SOA compensation-enabling robust operation without external protection circuitry. Its architecture maintains regulation across input voltages from 27 V to 38 V while sustaining 350 mA load current at full temperature range.

The device operates without mandatory input/output capacitors in low-noise, low-current applications but specifies 0.33 µF input and 0.1 µF output ceramic/tantalum bypassing for stability under dynamic loads and long PCB trace conditions. Output voltage drift is characterized at -1.2 mV/°C over temperature.

Key Specifications

Pinout & Package

DPAK (TO-252) surface-mount package with exposed thermal pad; footprint per ST standard STD-ST drawing (6.7 mm × 6.7 mm body, 1.8 mm height, 3.0 mm lead pitch).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78M24CDT-TR and MC78M24BDTG, L78M24ABDT-TR provides tighter voltage accuracy, wider temperature coverage, superior thermal performance in DPAK, and integrated SOA protection-making it the preferred choice for new industrial designs demanding reliability and precision.

Availability

L78M24ABDT-TR is available at Aetrix Electronics and suitable for industrial PLCs, motor drive logic supplies, analog sensor biasing, and legacy equipment retrofits requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for L78M24ABDT-TR 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 power management applications.

L78M24ABDT-TR belongs to the L78MxxA precision linear regulator product line, engineered specifically for industrial-grade local regulation where reliability, thermal resilience, and tight output tolerance are essential.

FAQ

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

The L78M24ABDT-TR requires a minimum input voltage of 26 V to maintain regulation at 350 mA due to its 2 V dropout voltage specification. At 500 mA, dropout increases slightly; design margin recommends VI ≥ 27 V for guaranteed operation across temperature and line variation.

Can this regulator be used without input and output capacitors?

Capacitors are not strictly mandatory for basic functionality, but ST specifies 0.33 µF input and 0.1 µF output capacitance for stability under all load conditions-including transient response and long PCB traces. Omitting them risks oscillation or poor ripple rejection, especially with high-impedance sources.

How does the SOA protection function during overload events?

SOA protection dynamically limits power dissipation in the internal pass transistor by reducing output current as the voltage across it rises-preventing second breakdown during sustained overloads or short circuits. This complements thermal shutdown and current limiting to provide three-layer fault protection.

Is the DPAK package thermally compatible with standard reflow profiles?

Yes-the DPAK package of L78M24ABDT-TR is qualified for standard lead-free reflow profiles (J-STD-020). Its exposed thermal pad must be soldered to a minimum 100 mm² copper pour with ≥4 thermal vias to achieve specified R_thJC of 8 °C/W; insufficient thermal relief degrades current capability and lifetime.