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onsemi MC78M12CDT
- Part No.:
- MC78M12CDT
- Manufacturer:
- onsemi
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
MC78M12CDT.pdf
- Description:
- IC REG LINEAR 12V 500MA DPAK
- Quantity:
- Payment:
- Shipping:
Inventory:3,211
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Product details
Overview
MC78M12CDT from onsemi is a 12 V, 500 mA fixed-output 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 12 V output across 5 mA–500 mA load with ±4% tolerance at 25°C and supports input voltages up to 35 V DC.
For engineers reviewing the MC78M12CDT datasheet, pinout, applications, or equivalent options, this device is selected for cost-sensitive, non-adjustable 12 V supply rails in industrial control modules, automotive body electronics, and embedded power subsystems where simplicity, reliability, and Pb-free compliance are critical.
Technical Context
The MC78M12CDT implements a monolithic three-terminal series pass architecture with PNP-based error amplifier and Darlington output stage. Its internal safe-area compensation dynamically reduces short-circuit current as VIN−VOUT increases, preventing second breakdown during overload.
Thermal protection activates at +150°C junction temperature, and current limiting holds peak output at 350 mA under short-circuit conditions at VIN = 35 V. Dropout voltage remains fixed at 2.0 V typical across operating temperature and load range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 12 V nominal, 11.5–12.5 V over full load/temperature range - ensures compatibility with 12 V logic and analog circuitry requiring tight regulation. |
| Max Output Current | 500 mA continuous with adequate heatsinking - supports mid-power microcontroller peripherals and sensor interfaces without external boost. |
| Input Voltage Range | 14.5–27 V DC input for 12 V output - accommodates automotive battery transients and unregulated 15–24 V industrial supplies. |
| Line Regulation | 8 mV typical (≤50 mV max) - maintains output stability despite ±2.5 V input variation, critical for noisy DC bus environments. |
| Ripple Rejection | 55 dB at 120 Hz, 100 mA load - suppresses rectified AC ripple from unfiltered SMPS or linear transformer supplies. |
| Dropout Voltage | 2.0 V typical - defines minimum headroom needed; enables operation from 14 V input while delivering clean 12 V output. |
| Quiescent Current | 3.2–6.0 mA - low static draw preserves efficiency in always-on subsystems like CAN node standby. |
Pinout & Package
DPAK-3 (TO-252) package with exposed thermal pad connected to Pin 2 (GND); heatsink surface electrically tied to ground for optimal thermal performance and EMI control.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Input | Unregulated DC input connection; requires ≥0.33 µF low-ESR bypass capacitor placed adjacent to pin for high-frequency stability. |
| Pin 2 | Ground | Common reference and thermal path; must be connected to large copper pour for thermal dissipation and noise immunity. |
| Pin 3 | Output | Regulated 12 V output; supports up to 500 mA; output capacitor ≥0.1 µF recommended for transient response. |
Key Features
| Feature | Design Value |
|---|---|
| No external components required | Self-contained regulation with integrated feedback, error amp, and pass transistor - eliminates external resistors/capacitors for basic 12 V supply. |
| Internal thermal overload protection | Automatic shutdown at +150°C junction temperature - prevents permanent damage during sustained overload or poor heatsinking. |
| Short-circuit current limiting | 350 mA hard limit under VIN = 35 V short - protects upstream supply and PCB traces without fuse dependency. |
| Safe-area compensated output transistor | Dynamic current foldback above 2 V VCE - avoids SOA violation during startup into capacitive loads or output shorts. |
| Pb-free DPAK-3 package | RoHS-compliant 6.10 × 6.54 mm footprint with thermal pad - enables automated reflow assembly and meets automotive environmental requirements. |
Applications
| Industrial PLC I/O Module | Automotive Body Control Unit |
|---|---|
Use Scenario: Powering isolated digital input conditioning circuits and relay drivers in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Local 12 V rail generator for optocoupler bias, level-shifting buffers, and solenoid interface ICs. Use Value: Eliminates need for external current-limiting resistors or discrete thermal protection, reducing BOM count by 3–5 parts per channel. | Use Scenario: Supplying door module microcontrollers, window motor drivers, and LED interior lighting. IC Role / Device Role / Timing Role: Primary 12 V regulator for non-safety-critical sub-systems operating across −40°C to +125°C ambient. Use Value: Withstands 35 V load-dump transients and maintains regulation during cold-crank (6.5 V min), ensuring firmware execution continuity. |
| Medical Infusion Pump Controller | Point-of-Sale Terminal Power |
Use Scenario: Providing clean 12 V for stepper motor drivers and display backlight inverters in Class II medical devices. IC Role / Device Role / Timing Role: Isolated auxiliary regulator downstream of main DC/DC converter, decoupling motor noise from sensitive analog sensors. Use Value: 55 dB ripple rejection attenuates switching noise from primary SMPS, preventing audible whine in piezo-driven pumps. | Use Scenario: Generating 12 V for thermal print head drivers and USB hub controllers in retail kiosks. IC Role / Device Role / Timing Role: Fixed-output LDO replacement for aging 7812 TO-220 designs, enabling smaller PCB area and lower profile. Use Value: DPAK-3 footprint reduces board space by 60% vs TO-220 while maintaining same thermal resistance to case (5.0°C/W). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC78M12BDTRKG | −40°C to +125°C operating range vs. 0°C to +125°C for MC78M12CDT; otherwise identical electrical specs and DPAK-3 package. | Suitable for automotive under-hood or industrial outdoor enclosures requiring extended temperature support. | Select MC78M12BDTRKG when ambient operating temperature may fall below 0°C; no layout or schematic changes needed. |
| LM78M12CDT | Same 12 V/500 mA spec but manufactured by Texas Instruments; dropout voltage 2.5 V typical (vs. 2.0 V), ripple rejection 45 dB at 120 Hz (vs. 55 dB). | Lower PSRR and higher dropout reduce margin in noisy or low-headroom systems; TI version lacks AEC-Q100 qualification. | Choose LM78M12CDT only if dual-sourcing is mandated and system tolerances accommodate 10 dB lower ripple rejection and 0.5 V higher dropout. |
Compared with MC78M12BDTRKG, the MC78M12CDT trades extended temperature range for lower cost in commercial-grade applications; versus LM78M12CDT, it delivers superior noise immunity and tighter dropout-critical for automotive and industrial edge nodes.
Availability
MC78M12CDT is available at Aetrix Electronics and suitable for industrial automation controllers, automotive body electronics, and medical device power subsystems requiring stable component supply and RoHS-compliant packaging.
Supply support for MC78M12CDT 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, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.
The MC78Mxx series was designed as a robust, drop-in replacement for legacy 78xx regulators-optimized for local regulation in space-constrained, thermally demanding applications without external compensation.
FAQ
What is the maximum input voltage rating for the MC78M12CDT?
The MC78M12CDT has an absolute maximum input voltage of 40 V DC for brief transients (e.g., automotive load dump), with continuous operation rated up to 35 V DC. Exceeding 35 V continuously risks thermal runaway due to power dissipation limits, especially above 50°C ambient. Always verify worst-case VIN in your design against the 35 V DC specification before finalizing the front-end filter.
Does the MC78M12CDT require an input bypass capacitor?
Yes, the MC78M12CDT requires a minimum 0.33 µF low-ESR capacitor (e.g., tantalum or ceramic) placed directly across Pins 1 and 2. This capacitor stabilizes the regulator under fast load transients and suppresses high-frequency noise from upstream sources. Omitting it may cause oscillation or output overshoot, particularly when fed from long PCB traces or switch-mode supplies.
Can the MC78M12CDT be used in automotive applications?
The MC78M12CDT is rated for 0°C to +125°C junction temperature and supports 35 V input-making it suitable for cabin-mounted automotive modules like infotainment or HVAC controls. However, for under-hood or safety-critical locations, the automotive-qualified MC78M12BDTRKG (−40°C to +125°C) or NCV78M12BDTRKG (AEC-Q100 qualified) is required instead of the MC78M12CDT.
What is the thermal resistance of the MC78M12CDT in its DPAK-3 package?
The MC78M12CDT in DPAK-3 (Case 369C) has a junction-to-case thermal resistance (θJC) of 5.0°C/W and a junction-to-air thermal resistance (θJA) of 92°C/W in free air. With a 1-inch² 2-oz copper pad, θJA improves to ~50°C/W. These values determine maximum power dissipation: at 50°C ambient, max continuous power is ~1.1 W without heatsink, rising to ~7.5 W with infinite heatsink.
How does the MC78M12CDT handle short-circuit conditions?
The MC78M12CDT limits short-circuit output current to 350 mA typical at VIN = 35 V, with automatic thermal shutdown engaging if junction temperature exceeds +150°C. Unlike older 78xx variants, it also employs safe-area compensation-reducing current as VIN−VOUT increases-to prevent second breakdown during sustained shorts. Recovery is automatic after cooldown.
MC78M12CDT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 35V
- Voltage - Output (Min/Fixed):
- 12V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- -
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- -
- Current - Supply (Max):
- -
- PSRR:
- 80dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Temperature, Short Circuit
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DPAK
MC78M12CDT FAQ
1.How can I place an order for MC78M12CDT through Aetrix?
Please submit a Request for Quotation (RFQ) for MC78M12CDT on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MC78M12CDT reliable?
The price and inventory of MC78M12CDT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC78M12CDT is usually 5 days.
3.What payment methods are accepted for MC78M12CDT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC78M12CDT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC78M12CDT?
MC78M12CDT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC78M12CDT order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MC78M12CDT?
For technical support, including MC78M12CDT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC78M12CDT requirements.
6.How does Aetrix verify that MC78M12CDT is sourced from the original manufacturer or authorized distributors?
All MC78M12CDT products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MC78M12CDT meets industry standards.
7.What is the process for return or replacement of MC78M12CDT?
All MC78M12CDT units undergo pre-shipment inspection (PSI). If there is an issue with MC78M12CDT, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MC78M12CDT part is unused and in its original packaging.
Return procedure for MC78M12CDT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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