onsemi MC78M15BDTG

Overview

MC78M15BDTG from onsemi is a 500 mA, 15 V fixed-output positive 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 delivers stable 15 V output across −40°C to +125°C junction temperature, with ±3% output voltage tolerance at 25°C and ≤300 mV load regulation (5–500 mA).

For engineers reviewing the MC78M15BDTG datasheet, pinout, applications, or equivalent options, this device is selected for industrial power rails, automotive subsystems requiring AEC-Q100-aligned reliability, and embedded systems needing robust, no-external-components regulation with 2.0 V dropout and 54 dB ripple rejection at 100 mA.

Technical Context

The MC78M15BDTG implements a monolithic three-terminal series pass architecture with built-in protection circuitry: thermal overload shutdown triggers at ~150°C junction temperature, short-circuit current limit holds peak output at 350 mA (typ), and safe-area compensation dynamically reduces short-circuit current as input-to-output differential increases.

It operates without external capacitors in low-noise, low-current applications but recommends ≥0.33 µF tantalum or ceramic input bypassing for stability under high-frequency transients or long trace conditions; output capacitance is not required for basic regulation but improves transient response.

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 automated assembly and thermal conduction through PCB copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC78M15BDTG, MC7815CD2TR4G trades surface-mount compactness and extended temperature range for tighter initial accuracy and through-hole mounting, while NCV78M15BDTRKG adds automotive qualification overhead without altering core regulation specs-making MC78M15BDTG optimal for cost-sensitive, high-reliability industrial designs.

Availability

MC78M15BDTG is available at Aetrix Electronics and suitable for industrial PLCs, automotive body electronics, and medical sensor modules requiring stable component supply with guaranteed long-term continuity.

Supply support for MC78M15BDTG 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 innovation for automotive, industrial, cloud, and IoT applications.

The MC78Mxx series was designed as a half-current variant of the classic 78xx family to serve space-constrained, thermally demanding applications where 500 mA output and DPAK packaging deliver optimal power density and manufacturability.

FAQ

What is the maximum input voltage rating for MC78M15BDTG?

The MC78M15BDTG has an absolute maximum input voltage of 40 Vdc, as specified in the Maximum Ratings table. Operation above 35 Vdc is not recommended for continuous use due to thermal stress; typical design practice limits input to ≤30 Vdc to maintain safe junction temperature under full 500 mA load.

Does MC78M15BDTG require an input bypass capacitor?

Yes, MC78M15BDTG requires a minimum 0.33 µF tantalum or ceramic capacitor placed directly across pins 1 (Input) and 2 (GND). This prevents oscillation under high-frequency transients and stabilizes regulation when connected via long traces or high-impedance sources, as confirmed in the Applications Information section.

What is the thermal resistance and heatsinking requirement for MC78M15BDTG at 500 mA?

MC78M15BDTG has θ_JC = 5.0°C/W. At 500 mA with 17 V input (2 V dropout), power dissipation is ~1 W; with 25°C ambient and no heatsink, junction temperature rises ~100°C above ambient. A minimum 1 cm² 2 oz. copper pad is required to sustain 500 mA continuously per Figure 2 in the datasheet.

Can MC78M15BDTG be used in adjustable configurations?

MC78M15BDTG is a fixed 15 V output device and cannot be adjusted. However, the datasheet shows it can serve as the reference element in an adjustable configuration using an external op-amp (Figure 11), where the minimum output becomes 17 V (15 V + 2 V headroom), preserving regulation integrity only above that threshold.

Is MC78M15BDTG pin-compatible with other 78Mxx devices in DPAK-3?

Yes, all MC78MxxxDTRKG and MC78MxxxBT variants in DPAK-3 share identical pinout (Input-GND-Output) and footprint. Voltage variants (e.g., MC78M05BDTG, MC78M12BDTG) are mechanically and electrically interchangeable on the same PCB layout, enabling design reuse across multiple rail voltages.