STMicroelectronics L78M05ABDT-TR

Overview

L78M05ABDT-TR from STMicroelectronics is a fixed-output +5 V, 500 mA positive linear voltage regulator in DPAK package, featuring ±2 % output voltage tolerance at 25 °C, thermal overload protection, short-circuit current limiting, and safe operating area (SOA) protection. It delivers stable local regulation for microcontroller power rails, sensor interfaces, and industrial control modules where input-to-output differential voltage exceeds 2 V.

For engineers reviewing the L78M05ABDT-TR datasheet, L78M05ABDT-TR pinout, L78M05ABDT-TR application, or L78M05ABDT-TR equivalent, key selection criteria include guaranteed -40 to 125 °C operating junction temperature range (AB grade), 2 V dropout voltage, 62 dB supply voltage rejection at 120 Hz, 40 µV RMS 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 integrated current limiting, thermal shutdown, and SOA compensation. Its architecture ensures robust operation without external components under typical loads, while supporting adjustable configurations via external resistors when needed.

The AB-grade variant guarantees full electrical performance across -40 to 125 °C junction temperature, with line regulation of ≤50 mV (VI = 8–25 V, IO = 200 mA) and load regulation of ≤50 mV (IO = 5–200 mA), enabling reliable use in automotive body electronics and industrial PLC I/O modules.

Key Specifications

Pinout & Package

The L78M05ABDT-TR is housed in a surface-mount DPAK (TO-252) package with exposed thermal pad for enhanced heat dissipation. Pin assignment follows standard three-terminal regulator configuration: Input, Ground, Output.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78M05CDT-TR and MC78M05BDTG, the L78M05ABDT-TR uniquely combines automotive-grade temperature range, surface-mount DPAK packaging, and 8 °C/W junction-to-case thermal resistance-enabling higher sustained current in compact, reflow-soldered industrial modules.

Availability

L78M05ABDT-TR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical diagnostic sensors, and point-of-sale terminal logic rails requiring stable component supply with guaranteed long-term availability.

Supply support for L78M05ABDT-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 consumer markets since 1987.

The L78MxxA series was developed to provide rugged, drop-in fixed-voltage regulation for harsh-environment embedded systems-emphasizing thermal resilience, fault tolerance, and ease of integration without external protection circuitry.

FAQ

What is the minimum input voltage required for regulation?

The L78M05ABDT-TR requires a minimum input-to-output differential of 2 V to maintain regulation. For a nominal 5 V output, this means VI ≥ 7 V under all load and temperature conditions. At higher temperatures or near maximum current, a 2.5 V headroom is recommended to ensure stability.

Can this regulator be used without input/output capacitors?

No. A 0.33 µF input capacitor (tantalum or ceramic) and 0.1 µF output ceramic capacitor are mandatory per ST's design guidelines. Omitting them risks oscillation, poor transient response, and failure to meet specified line/load regulation or noise performance.

Is the DPAK package RoHS-compliant and lead-free?

Yes. The L78M05ABDT-TR carries ST's ECOPACK®2 designation, confirming full compliance with RoHS Directive 2011/65/EU and lead-free soldering compatibility (reflow profile JEDEC J-STD-020D). The device uses matte tin terminations and halogen-free molding compound.

How does thermal shutdown behave during overload?

When junction temperature exceeds ~165 °C, the internal thermal limiter disables the pass transistor until temperature falls below ~145 °C. This cycle repeats autonomously-no latch-up occurs-and protects against permanent damage during sustained short-circuit or excessive ambient conditions.