STMicroelectronics L78M08ABDT-TR

Overview

L78M08ABDT-TR from STMicroelectronics is a three-terminal positive fixed-voltage linear regulator delivering 8 V at up to 500 mA output current, featuring ±2 % output voltage tolerance, thermal overload protection, short-circuit protection, and safe operating area (SOA) protection. It operates across –40 °C to +125 °C and is used for local on-card regulation in industrial power supplies and embedded control modules.

For engineers reviewing the L78M08ABDT-TR datasheet, L78M08ABDT-TR pinout, L78M08ABDT-TR application, or L78M08ABDT-TR equivalent, key selection criteria include dropout voltage (2 V), load regulation (80 mV max over 5–200 mA), supply voltage rejection (56 dB at 120 Hz), output noise (52 µV RMS), and extended temperature range support.

Technical Context

This device implements a monolithic silicon voltage regulator with internal current limiting, thermal shutdown, and SOA compensation-enabling robust operation without external protection circuitry. Its architecture ensures stable regulation under transient load steps and line variations while maintaining tight DC accuracy over temperature.

Designed for fixed-output use, it supports external configuration for adjustable voltage or current boosting via external pass transistors. Input voltage range is 10.5 V to 25 V for nominal 8 V output, with guaranteed operation up to 35 V input under fault conditions.

Key Specifications

Pinout & Package

The L78M08ABDT-TR is housed in a DPAK (TO-252) surface-mount package with exposed thermal pad for enhanced heat dissipation. Thermal resistance junction-to-ambient is 100 °C/W, requiring PCB copper area for thermal management in high-current applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2931T-8.0/NOPB and TLV73308PDBVR, the L78M08ABDT-TR delivers 5× more output current than the TLV733 series and 5× more than the LM2931, while offering superior thermal robustness and SOA protection-making it the only choice among the three for industrial 500 mA applications requiring extended temperature operation.

Availability

L78M08ABDT-TR is available at Aetrix Electronics and suitable for industrial automation controllers, automotive body electronics, medical sensor interfaces, and point-of-sale terminal power systems requiring stable component supply across long production lifecycles.

Supply support for L78M08ABDT-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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The L78MxxA series was developed to provide rugged, cost-effective fixed-voltage regulation for local power domains in harsh environments-emphasizing reliability, thermal resilience, and ease of integration without external protection components.

FAQ

What is the maximum input voltage for L78M08ABDT-TR?

The absolute maximum DC input voltage is 35 V for output voltages between 5 V and 18 V. Exceeding this risks permanent damage. For reliable operation at 8 V output, the recommended input range is 10.5 V to 25 V to maintain adequate headroom and thermal margin.

Does L78M08ABDT-TR require input and output capacitors?

Yes: a minimum 0.33 µF input capacitor (tantalum, ceramic, or film) is required for stability with long input traces; a minimum 0.1 µF output ceramic capacitor is mandatory for transient response and loop stability. Larger values improve ripple rejection but do not substitute for proper layout.

Can L78M08ABDT-TR be used in adjustable configurations?

Yes-by adding external resistors and a pass transistor, it can be configured as an adjustable regulator (7.0–20 V) or current booster. The datasheet provides Figure 18 (adjustable output) and Figure 19 (current boost) with design equations and component selection guidance.

How does thermal performance differ between DPAK and TO-220 packages?

DPAK (L78M08ABDT-TR) has R_thJA = 100 °C/W; TO-220 (L78M08AB) has R_thJA = 50 °C/W. At 500 mA and 2 V dropout (1 W dissipation), DPAK junction rise is ~100 °C above ambient-requiring ≥250 mm² copper pour-while TO-220 needs only minimal heatsinking for same conditions.