onsemi MC78M05ABTG

Overview

MC78M05ABTG from onsemi is a 5.0 V, ±2% accuracy, 500 mA fixed-output linear voltage regulator in TO-220 package with internal thermal shutdown, short-circuit current limiting, and safe-area compensation. It delivers stable local regulation for industrial control, automotive body electronics, and embedded power supplies where input voltage ranges from 7.0 V to 35 V.

For engineers reviewing the MC78M05ABTG datasheet, pinout, applications, or equivalent options, key selection criteria include output voltage tolerance (±2%), dropout voltage (2.0 V), ripple rejection (62 dB at 120 Hz), junction temperature range (−40°C to +125°C), and Pb-free TO-220 packaging with heatsink-connected ground pin.

Technical Context

The MC78M05ABTG implements a monolithic three-terminal series pass regulator architecture with built-in protection circuitry: thermal overload shutdown activates at +150°C junction temperature, short-circuit current limit holds peak output at 350 mA under fault, and safe-area compensation dynamically reduces short-circuit current as pass transistor V_CE increases.

It operates across −40°C to +125°C ambient (T_J = −40°C to +125°C), supports up to 35 V DC input, and maintains 5.0 V output with ≤50 mV line regulation (7–25 V input) and ≤20 mV load regulation (5–200 mA load), enabling robust performance in noisy, wide-input industrial environments without external compensation.

Key Specifications

Pinout & Package

MC78M05ABTG uses the TO-220 (Case 221AB) package with exposed metal tab thermally and electrically connected to Pin 2 (Ground). The heatsink surface must be isolated from other potentials unless intentionally tied to system ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC78M05CDTG, MC78M05ABTG offers tighter ±2% regulation and −40°C capability for harsh environments; versus NCV78M05ABDTRKG, it provides TO-220 mechanical robustness and simplified heatsinking but lacks automotive certification documentation.

Availability

MC78M05ABTG is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and medical device power supply designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MC78M05ABTG 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 manufacturer specializing in energy-efficient power management, analog, and sensing solutions for automotive, industrial, and cloud infrastructure markets.

The MC78M00A series was designed to deliver high-accuracy, rugged linear regulation for mission-critical embedded systems where reliability, thermal resilience, and minimal external components are essential.

FAQ

What is the maximum input voltage rating for MC78M05ABTG?

The MC78M05ABTG has an absolute maximum input voltage of 40 V DC, though its recommended operating range is 7.0 V to 35 V DC. Exceeding 35 V risks exceeding safe power dissipation limits, especially at elevated ambient temperatures. Always verify thermal design using θ_JA = 70°C/W (free air) or θ_JC = 5.0°C/W (with heatsink) per the datasheet.

Does MC78M05ABTG require an input bypass capacitor?

Yes - a minimum 0.33 µF tantalum or low-ESR ceramic capacitor is required across the input pins of MC78M05ABTG to ensure stability, especially when connected via long traces or high-inductance wiring. This capacitor mitigates high-frequency noise and prevents oscillation under dynamic load conditions.

Can MC78M05ABTG be used in automotive applications?

MC78M05ABTG itself is not AEC-Q100 qualified, but its functionally identical variant NCV78M05ABDTRKG is certified for automotive use. For production automotive ECUs, specify the NCV prefix part; MC78M05ABTG remains suitable for prototyping, service units, or non-safety-critical aftermarket systems where full qualification is not mandated.

What is the thermal resistance and heatsinking requirement for MC78M05ABTG?

MC78M05ABTG in TO-220 package has θ_JC = 5.0°C/W and θ_JA = 70°C/W (free air). To sustain 500 mA at 35 V input (2.0 V dropout), junction temperature must stay below +150°C. With 25°C ambient, a heatsink with θ_SA ≤ 20°C/W is recommended - verified via thermal calculation: T_J = T_A + P_D × (θ_JA or θ_JC + θ_SA).

How does the safe-area compensation feature protect MC78M05ABTG during output shorts?

Safe-area compensation in MC78M05ABTG dynamically reduces short-circuit current as the pass transistor's collector-emitter voltage (V_CE) increases - preventing second breakdown by keeping the device within its SOA (Safe Operating Area) boundary. During a short, output current drops from ~350 mA toward ~100 mA as V_CE rises, allowing safe thermal recovery without latch-up or destruction.