onsemi MC78M05ACDT

Overview

MC78M05ACDT from onsemi is a 5.0 V, 500 mA fixed-output linear voltage regulator in DPAK-3 (TO-252) package with ±2% output accuracy, internal thermal shutdown, and short-circuit current limiting. It delivers stable local regulation for microcontroller power rails, sensor interfaces, and industrial control modules requiring low-noise, rugged DC supply.

For engineers reviewing the MC78M05ACDT datasheet, pinout, applications, or equivalent options, this page provides verified electrical specs, thermal performance data, real-world use cases, and validated alternative parts for automotive-grade 5 V supply design.

Technical Context

The MC78M05ACDT implements a monolithic NPN pass transistor with safe-area compensation, enabling robust operation under transient overload and thermal stress. Its dropout voltage is 2.0 V at 25°C, supporting input voltages up to 35 V while maintaining regulation down to 7.0 V input.

It features internal current limiting (350 mA typical short-circuit current), ripple rejection of 62 dB at 120 Hz (100 mA load), and output noise of 40 µV RMS (10 Hz–100 kHz). The device operates across 0°C to +125°C junction temperature range and includes Pb-free packaging compliant with RoHS.

Key Specifications

Pinout & Package

DPAK-3 (TO-252) package with exposed thermal pad (pin 2 connected to GND and heatsink surface); compact 6.10 × 6.54 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, the MC78M05ACDT offers tighter output accuracy critical for precision analog subsystems; versus NCV78M05ABDTRKG, it trades automotive qualification for lower unit cost in commercial/industrial designs where extended temperature is unnecessary.

Availability

MC78M05ACDT is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and point-of-sale terminal designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MC78M05ACDT 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 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, thermally robust linear regulation for space-constrained embedded systems where simplicity, reliability, and low EMI are essential-replacing discrete regulator designs with single-chip solutions.

FAQ

What is the maximum input voltage rating for MC78M05ACDT?

The MC78M05ACDT has an absolute maximum input voltage of 35 V DC. Operation above this level risks permanent damage due to internal junction breakdown. For reliable 5.0 V output at 500 mA, input should remain between 7.0 V and 24 V to maintain adequate dropout margin and thermal headroom.

Does MC78M05ACDT require an input bypass capacitor?

Yes, MC78M05ACDT requires a minimum 0.33 µF tantalum or ceramic capacitor placed directly across pins 1 (Input) and 2 (GND). This stabilizes the regulator under dynamic load changes and suppresses high-frequency noise from upstream switching supplies-omission may cause oscillation or output ripple exceeding specification.

How does the thermal performance of MC78M05ACDT compare to TO-220 versions?

MC78M05ACDT in DPAK-3 achieves 5.0°C/W junction-to-case thermal resistance-identical to TO-220 variants-but relies entirely on PCB copper area for heatsinking. With 1 in² (645 mm²) of 2 oz. copper, its junction temperature rise is ~25°C at 500 mA, whereas TO-220 allows bolt-on heatsinks for higher ambient operation.

Can MC78M05ACDT be used in adjustable output configurations?

MC78M05ACDT is a fixed 5.0 V device and cannot be adjusted via external resistors. However, it can serve as the reference element in external op-amp circuits (e.g., using MC1741) to generate higher or intermediate voltages-minimum output in such configurations is 7.0 V (5.0 V + 2.0 V headroom).

What is the short-circuit current limit of MC78M05ACDT?

The MC78M05ACDT limits short-circuit output current to 350 mA typical at TJ = 25°C and VI = 35 V. This internal current limiting-combined with thermal shutdown-prevents destructive failure during sustained output faults, allowing safe recovery once the fault is removed.