onsemi MC78M08CDT

Overview

MC78M08CDT from onsemi is a 500 mA, fixed +8.0 V 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 output under load currents up to 500 mA with ≤80 mV load regulation and ≥56 dB ripple rejection at 100 mA, commonly used in industrial power supplies and embedded control modules.

For engineers reviewing the MC78M08CDT datasheet, pinout, applications, or equivalent options, key selection criteria include its 8.0 V ±3% output accuracy over temperature, 2.0 V dropout voltage, 35 V absolute maximum input, and Pb-free DPAK-3 thermal performance with θ_JA = 92°C/W and θ_JC = 5.0°C/W.

Technical Context

The MC78M08CDT implements a monolithic three-terminal series pass regulator 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, and safe-area compensation dynamically reduces short-circuit current as V_IN–V_OUT increases.

It operates across an input range of 10.5 V to 25 V DC for nominal 8.0 V output, supports continuous 500 mA load with adequate PCB copper heatsinking, and maintains output stability without external capacitors in most low-noise applications-though 0.33 µF input bypassing is recommended for long trace or high-capacitance load conditions.

Key Specifications

Pinout & Package

DPAK-3 (TO-252) package with exposed thermal pad connected to Pin 2 (GND); standard 3-pin configuration optimized for surface-mount thermal management and board-level decoupling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC78M08CDT, MC78M08BDTRKG extends cold-temperature operation without altering thermal or electrical behavior, while NCV78M08BDTRKG adds automotive-grade reliability validation-neither offers higher current or lower dropout, making MC78M08CDT optimal for cost-sensitive industrial applications within 0°C–125°C.

Availability

MC78M08CDT is available at Aetrix Electronics and suitable for industrial control systems, sensor signal conditioning, and legacy equipment repair requiring stable component supply with consistent DPAK-3 packaging and RoHS compliance.

Supply support for MC78M08CDT 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 silicon solutions for automotive, industrial, cloud, and IoT applications.

The MC78M00 series was designed as a robust, drop-in upgrade to legacy 78xx regulators-delivering 500 mA output in compact DPAK-3 or TO-220 packages with enhanced thermal protection and industrial temperature grading.

FAQ

What is the maximum input voltage rating for the MC78M08CDT?

The MC78M08CDT has an absolute maximum input voltage of 35 V DC. Operation above 25 V is permitted only for transient conditions; continuous operation should remain within 10.5 V to 25 V to ensure specified output regulation and thermal safety. Exceeding 35 V risks permanent damage to the internal pass transistor and protection circuitry.

Does the MC78M08CDT require an input bypass capacitor?

Yes, the MC78M08CDT requires a minimum 0.33 µF input bypass capacitor placed directly across Pins 1 and 2. This capacitor stabilizes the regulator under high-frequency load transients and suppresses noise from upstream sources-especially critical when input traces exceed 2 inches or when driving large capacitive loads. Tantalum or ceramic types with low ESR are preferred.

What is the thermal resistance and power dissipation capability of the MC78M08CDT in its DPAK-3 package?

The MC78M08CDT in DPAK-3 package has θ_JA = 92°C/W and θ_JC = 5.0°C/W. With 2 oz. copper on the PCB, it can dissipate up to 7.52 W at 50°C ambient. At 500 mA load and 2.0 V dropout, power dissipation is 1.0 W-well within safe limits without additional heatsinking under typical industrial conditions.

Can the MC78M08CDT be used in automotive applications?

The MC78M08CDT is rated for 0°C to +125°C operation and meets industrial requirements but is not AEC-Q100 qualified. For automotive applications, use the NCV78M08BDTRKG variant instead, which includes automotive-grade process controls, extended temperature validation, and PPAP documentation-ensuring compliance with OEM reliability standards that the MC78M08CDT does not provide.

How does the MC78M08CDT compare to the MC7808 series in terms of output current and package options?

The MC78M08CDT delivers 500 mA output-exactly half the 1.0 A rating of the MC7808-but shares identical electrical characteristics, pinout, and protection features. It is offered exclusively in surface-mount DPAK-3 (TO-252), whereas MC7808 is typically available in through-hole TO-220. The MC78M08CDT thus enables higher-density PCB layouts while maintaining functional equivalence for lower-current applications.