onsemi MC78M09CDTRK

Overview

MC78M09CDTRK from onsemi is a 500 mA, fixed +9.0 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 11.5–23 V input, supports peak currents up to 700 mA, and is rated for 0°C to +125°C operation in industrial power supplies and embedded control modules.

For engineers reviewing the MC78M09CDTRK datasheet, pinout, applications, or equivalent options, key selection criteria include its ±3% output voltage accuracy at 25°C (8.64–9.45 V), 2.0 V dropout, 56 dB ripple rejection at 120 Hz/100 mA, and DPAK-3 thermal resistance (θ_JA = 92°C/W, θ_JC = 5.0°C/W).

Technical Context

The MC78M09CDTRK 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 output at ~350 mA under fault, and safe-area compensation dynamically reduces short-circuit current as V_IN−V_OUT increases - preventing pass transistor destruction during overloads.

It operates without external components for basic regulation but requires an input bypass capacitor (≥0.33 µF) when connected via long traces or driving large capacitive loads. Its fixed 9.0 V output is trimmed at wafer level; no adjustment pins or feedback resistors are present, distinguishing it from adjustable LDOs or switching regulators.

Key Specifications

Pinout & Package

DPAK-3 (TO-252) package: surface-mount, 3-pin, exposed thermal pad (connected to Pin 2). Dimensions: 6.10 × 6.54 × 2.28 mm, pitch 2.29 mm. Heatsink surface electrically tied to ground terminal for low-impedance thermal path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78M09CDT/NOPB, MC78M09CDTRK offers 6 dB better ripple rejection and 2.8 mA lower quiescent current - directly improving noise immunity and standby power in battery-backed systems; versus NCV78M09BDTRKG, it trades automotive qualification for lower unit cost and broader commercial temperature range (0°C to +125°C vs. −40°C to +105°C).

Availability

MC78M09CDTRK is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and point-of-sale terminal designs requiring stable component supply, RoHS compliance, and DPAK-3 surface-mount compatibility.

Supply support for MC78M09CDTRK 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, sensor, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The MC78M00 series was designed as a robust, drop-in replacement for legacy 78xx regulators - delivering half the current (500 mA) of the MC7800 family while maintaining identical pinout, protection features, and ease of use in local voltage regulation.

FAQ

What is the maximum input voltage rating for MC78M09CDTRK?

The absolute maximum input voltage for MC78M09CDTRK is 40 Vdc, as specified in the Maximum Ratings table. However, for reliable operation within specifications, the recommended input range is 11.5 Vdc to 23 Vdc. Exceeding 23 Vdc may degrade line regulation and increase thermal stress, especially at full 500 mA load. The device's internal protection remains active up to 40 Vdc, but sustained operation above 23 Vdc requires careful thermal design.

Does MC78M09CDTRK require an input bypass capacitor?

Yes, MC78M09CDTRK requires an input bypass capacitor - typically ≥0.33 µF tantalum or ceramic - placed as close as possible to Pins 1 and 2. This capacitor stabilizes the regulator under fast load transients and suppresses high-frequency noise from upstream sources. Omitting it risks oscillation or erratic behavior, particularly when input traces exceed 2 inches or when driving capacitive loads >10 µF. The datasheet explicitly recommends this for all applications except very low-current, short-trace configurations.

Can MC78M09CDTRK be used in automotive applications?

MC78M09CDTRK is rated for 0°C to +125°C junction temperature and meets industrial reliability standards, but it is not AEC-Q100 qualified. For production automotive applications requiring qualification, the pin-compatible NCV78M09BDTRKG (AEC-Q100 Grade 2, −40°C to +105°C) is the designated alternative. MC78M09CDTRK may be used in non-safety, aftermarket, or development-stage automotive projects where formal qualification is not mandated.

What is the thermal resistance of MC78M09CDTRK in DPAK-3 package?

MC78M09CDTRK in DPAK-3 package has θ_JA = 92°C/W (junction-to-air, free-air condition) and θ_JC = 5.0°C/W (junction-to-case). These values assume the exposed thermal pad is soldered to a minimum 1 cm² copper area on the PCB. Without copper heatsinking, dissipation is limited to ~0.5 W at 70°C ambient - sufficient for ~250 mA at 9 V output. Adding 2 oz. copper and thermal vias can reduce θ_JA to ~40°C/W, enabling full 500 mA operation.

How does the safe-area compensation feature protect MC78M09CDTRK during overload?

Safe-area compensation in MC78M09CDTRK dynamically reduces short-circuit current as the input-to-output differential voltage (V_IN−V_OUT) increases. For example, at 35 V input and 9 V output (26 V differential), the short-circuit current drops below the 350 mA typical value - preventing the pass transistor from exceeding its SOA (Safe Operating Area) and avoiding second breakdown. This differs from simple current limiting and is critical for survival during high-voltage fault conditions like accidental 24 V connection to a 12 V system.