STMicroelectronics L78M05ABV-DG

Overview

L78M05ABV-DG from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a precise 5 V output at up to 500 mA, featuring ±2 % output voltage tolerance over −40 °C to +125 °C, thermal overload protection, and short-circuit current limiting. It operates with a 2 V dropout voltage and supports local on-card regulation in industrial power supplies, microcontroller subsystems, and sensor interface circuits.

For engineers reviewing the L78M05ABV-DG datasheet, L78M05ABV-DG pinout, L78M05ABV-DG application, or L78M05ABV-DG equivalent, key selection criteria include guaranteed extended-temperature operation (−40 °C to +125 °C), DPAK package thermal resistance (R_thJA = 100 °C/W), 62 dB supply voltage rejection at 120 Hz, and internal safe-area protection for robust load transients.

Technical Context

This regulator employs a monolithic bipolar pass transistor with internal current limiting, thermal shutdown, and output transition safe-operating-area (SOA) compensation. Its fixed 5 V output is stabilized across input voltages from 7 V to 20 V and load currents from 5 mA to 500 mA.

Designed for local regulation, it eliminates single-point distribution losses and requires only 0.33 µF input and 0.1 µF output ceramic or tantalum bypass capacitors for stable operation - no external feedback network needed. Quiescent current remains tightly controlled at 6 mA ±0.8 mA across operating conditions.

Key Specifications

Pinout & Package

The L78M05ABV-DG is housed in a surface-mount DPAK (TO-252) package with exposed thermal pad for enhanced heat dissipation. R_thJA = 100 °C/W and R_thJC = 8 °C/W enable reliable 500 mA operation with minimal PCB copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78M05CDT-TR and MC78M05BDTG, the L78M05ABV-DG uniquely guarantees ±2 % accuracy and full functionality from −40 °C, making it the sole choice for industrial and automotive applications demanding both precision and wide-temperature reliability.

Availability

L78M05ABV-DG is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical patient monitor front-ends, and point-of-sale terminal power management requiring stable component supply across extended temperature ranges.

Supply support for L78M05ABV-DG 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.

The L78MxxA series belongs to ST's precision linear regulator product line, engineered specifically for robust local regulation in harsh-temperature environments where reliability and tight output tolerance outweigh switching efficiency demands.

FAQ

What is the minimum input voltage required for stable 5 V output?

The L78M05ABV-DG requires a minimum input-to-output differential of 2 V to maintain regulation. With a nominal 5 V output, this means the input voltage must remain ≥7 V under all load and temperature conditions. At 500 mA load and 125 °C junction temperature, the dropout may increase slightly; design margin should include ≥7.5 V minimum input.

Can this regulator be used without input or output capacitors?

No. The datasheet mandates a minimum 0.33 µF input capacitor placed directly across IN and GND, and a 0.1 µF output capacitor between OUT and GND. Omitting either risks oscillation, poor transient response, or thermal runaway. Tantalum or ceramic types with low ESR are recommended; aluminum electrolytics are discouraged due to high impedance at high frequencies.

Does the DPAK package require a thermal pad connection to PCB copper?

Yes. The DPAK package features an exposed thermal pad that must be soldered to a dedicated PCB copper pour connected to the GND net. This pad is electrically tied to the GND terminal and is essential for achieving the specified R_thJA = 100 °C/W. Without proper thermal pad attachment, junction temperature will exceed safe limits at >200 mA load.

How does the internal short-circuit protection behave during a sustained fault?

During a sustained short, the L78M05ABV-DG limits output current to ~300 mA (typical) and initiates thermal shutdown if junction temperature exceeds ~150 °C. Once the fault clears and temperature drops below ~140 °C, the device automatically resumes regulation without requiring power-cycle reset - a feature critical for unattended industrial systems.