onsemi MC78M05BDTT5G

Overview

MC78M05BDTT5G from onsemi is a 5.0 V, 500 mA fixed-output linear voltage regulator in DPAK-3 (TO-252) package, featuring internal thermal shutdown, short-circuit current limiting, and safe-area compensation for rugged local regulation. It operates across −40°C to +125°C and delivers ±2% output accuracy at 25°C with 2.0 V dropout voltage.

For engineers reviewing the MC78M05BDTT5G datasheet, pinout, applications, or equivalent options, key selection criteria include automotive-grade temperature range (−40°C to +125°C), Pb-free DPAK-3 packaging, guaranteed 500 mA continuous output, and ripple rejection ≥62 dB at 120 Hz - critical for noise-sensitive power rails in engine control units and industrial sensors.

Technical Context

This three-terminal positive regulator uses an internal NPN pass transistor with safe-area compensation to limit short-circuit energy dissipation. Its thermal overload protection activates when junction temperature exceeds +150°C, and current limiting holds peak output at ~350 mA under short-circuit conditions at VI = 35 V.

The device requires no external components for basic operation but benefits from a 0.33 µF input bypass capacitor for stability with long trace lengths or large load capacitance. Dropout voltage remains stable at 2.0 V across temperature and load, enabling reliable regulation from 7.0 V minimum input up to 35 V maximum.

Key Specifications

Pinout & Package

DPAK-3 (TO-252) surface-mount package with exposed thermal pad (pin 2 connected to GND). Compact 6.10 × 6.54 × 2.28 mm footprint optimized for high-power density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC78M05CDTRKG, MC78M05BDTT5G provides tighter initial accuracy and wider temperature coverage; compared with NCV78M05BDTRKG, it shares core specs but lacks formal AEC-Q100 documentation - making it appropriate for automotive-adjacent industrial applications where certification isn't mandated.

Availability

MC78M05BDTT5G is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC modules, medical sensor interfaces, and telecom remote radio units requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC78M05BDTT5G 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics, delivering silicon solutions for automotive, industrial, cloud, and IoT markets.

The MC78M00 series was designed as a rugged, drop-in replacement for legacy 78xx regulators - optimized for local voltage regulation in harsh environments with integrated protection and extended temperature capability.

FAQ

What is the maximum input voltage rating for MC78M05BDTT5G?

The MC78M05BDTT5G has an absolute maximum input voltage of 40 Vdc for devices rated at 5.0–18 V output. This rating applies across its full operating temperature range and ensures safe operation even during load dump transients in automotive 12 V systems. Exceeding 40 V risks permanent damage due to internal junction breakdown.

Does MC78M05BDTT5G require an input bypass capacitor?

Yes, MC78M05BDTT5G requires a minimum 0.33 µF input bypass capacitor placed directly across pins 1 and 2. This capacitor stabilizes regulation under high-frequency noise and long PCB trace inductance - especially critical in automotive and industrial settings. Tantalum or ceramic types with low ESR are recommended for optimal transient response.

What is the thermal resistance (θ_JA) of MC78M05BDTT5G in standard PCB layout?

For MC78M05BDTT5G in DPAK-3 package mounted on 1 in² (6.45 cm²) of 2-oz copper, θ_JA is 92°C/W. With 2 in² copper and thermal vias to inner layers, it improves to ~50°C/W. The datasheet specifies θ_JC = 5.0°C/W, confirming efficient heat transfer from junction to the exposed thermal pad (pin 2).

Can MC78M05BDTT5G be used in parallel to increase output current?

No, MC78M05BDTT5G is not designed for parallel operation. Its output voltage tolerance (±2%) and lack of current-sharing features cause unequal load division and potential thermal runaway. For >500 mA requirements, use a single higher-current regulator (e.g., MC78T05) or implement external current boosting with a PNP transistor as documented in Figure 12 of the datasheet.

Is MC78M05BDTT5G pin-compatible with older TO-220 versions like MC78M05BTG?

No, MC78M05BDTT5G (DPAK-3) is not pin-compatible with TO-220 variants such as MC78M05BTG. While both share identical pin functional assignments (Input-GND-Output), the DPAK-3 has a different mechanical footprint, thermal pad orientation, and lead pitch (2.29 mm vs. 2.54 mm). PCB layout redesign is required for migration between packages.