onsemi L78M05T-E

Overview

L78M05T-E from SANYO is a monolithic linear 5V fixed-output voltage regulator delivering up to 500mA, featuring on-chip thermal protection, overcurrent limiting, and ASO (Avalanche Safe Operating Area) protection in a TP-3H surface-mount package - used for stable local power regulation in industrial control modules, sensor interfaces, and embedded microcontroller supply rails.

For engineers reviewing the L78M05T-E datasheet, pinout, applications, or equivalent options, key selection criteria include its 5V ±2% output accuracy at 350mA, 2.0V dropout at full load, 62dB ripple rejection at 120Hz, 40μV output noise (10Hz–100kHz), and thermal shutdown behavior under sustained overload.

Technical Context

The L78M05T-E implements a classic series-pass linear regulator architecture with internal NPN pass transistor, precision bandgap reference, error amplifier, and integrated protection circuitry. Its thermal protector activates at junction temperatures exceeding safe operating limits, while the on-chip overcurrent limiter holds peak output current to 300mA during short-circuit events and supports 700mA peak transient capability.

Designed for direct replacement of legacy 78Lxx and 78Mxx regulators, it operates across an input range of 7.5V–20V with guaranteed stability using only 0.33μF input and 0.1μF output ceramic capacitors. The TP-3H package enables compact PCB layout and enhanced thermal performance when surface-mounted on copper-poured areas.

Key Specifications

Pinout & Package

The L78M05T-E uses the TP-3H 3-pin surface-mount package (SANYO designation), with pin 1 = INPUT, pin 2 = GND, pin 3 = OUTPUT. Thermal performance scales with copper foil area on PCB; 50×50mm² board area enables ~1.0W dissipation at 25°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with L78M05T-E, the STMicro L78M05ABDT-TR offers greater thermal headroom in larger packages but omits ASO hardening, while the ON Semi MC78M05BDTRKG extends temperature range for automotive use yet does not specify avalanche-safe operation - making L78M05T-E uniquely suited for industrial equipment exposed to inductive load transients.

Availability

L78M05T-E is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and automotive body electronics requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for L78M05T-E 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

SANYO Electric Co., Ltd. was a Japanese semiconductor manufacturer specializing in power management, analog ICs, and optoelectronics before its acquisition by Panasonic in 2012; known for rugged, application-focused linear regulators.

The L78M00T Series was designed for cost-sensitive, space-constrained industrial and automotive auxiliary power applications demanding high reliability under thermal and electrical stress without external protection components.

FAQ

What is the maximum input voltage rating for the L78M05T-E?

The L78M05T-E has a maximum supply voltage rating of 35V at pin 1 (INPUT), as specified in the Absolute Maximum Ratings table. Operation above this voltage - even momentarily - risks permanent device failure. For reliable 5V output, the recommended input range is 7.5V to 20.0V per the Recommended Operating Conditions, ensuring adequate headroom while avoiding excessive power dissipation in the L78M05T-E.

Does the L78M05T-E require external capacitors, and what values are recommended?

Yes, the L78M05T-E requires external capacitors for stability: a minimum 0.33μF ceramic capacitor between INPUT and GND, and a minimum 0.1μF ceramic capacitor between OUTPUT and GND, both placed as close as possible to their respective pins. These values are validated in the Specified Test Circuit and ensure phase margin and transient response meet specification across temperature and load conditions for the L78M05T-E.

How does the thermal protection in the L78M05T-E behave during overload?

The L78M05T-E features an integrated thermal protector that disables the output when junction temperature exceeds safe limits, typically during sustained overload or inadequate PCB heat sinking. Once the die cools below the hysteresis threshold, the L78M05T-E automatically resumes regulation without requiring power cycle or external reset - a self-recovering safety mechanism confirmed in the Features section and thermal test conditions.

Is the L78M05T-E pin-compatible with other 78Mxx-series regulators from different manufacturers?

The L78M05T-E uses the TP-3H package with pin 1 = INPUT, pin 2 = GND, pin 3 = OUTPUT - identical pinout to industry-standard 3-pin SOT-223 and DPAK variants. While electrically similar to equivalents like MC78M05BDTRKG, true pin compatibility depends on mechanical footprint; TP-3H differs from SOT-223 in pad layout and thermal pad configuration, so PCB redesign is required when substituting L78M05T-E for non-TP-3H parts.

What is the typical output voltage tolerance of the L78M05T-E across operating conditions?

The L78M05T-E delivers 4.8V to 5.2V (±2%) at Tj = 25°C and IOUT = 350mA, with broader operational tolerance of 4.75V to 5.25V across input voltages of 7V–20V and loads from 5mA to 350mA. This 5% total window accounts for line regulation (≤25mV), load regulation (≤50mV), and temperature drift - all verified in the Operating Characteristics table for the L78M05T-E specifically.