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onsemi MC78M12ACDT
- Part No.:
- MC78M12ACDT
- Manufacturer:
- onsemi
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
MC78M12ACDT.pdf
- Description:
- IC REG LINEAR 12V 500MA DPAK
- Quantity:
- Payment:
- Shipping:
Inventory:2,406
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Product details
Overview
MC78M12ACDT from onsemi is a 500 mA, 12 V fixed-output linear voltage regulator in DPAK-3 (TO-252) package, featuring ±2% output accuracy, internal thermal shutdown, short-circuit current limiting, and safe-area compensation for rugged local regulation. It delivers stable 12 V power to microcontrollers, sensors, and analog circuitry in industrial control modules where input voltage ranges from 14.5 V to 27 V.
For engineers reviewing the MC78M12ACDT datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed ±2% initial output tolerance at 25°C, dropout voltage of 2.0 V max, ripple rejection ≥55 dB at 120 Hz, peak output current up to 700 mA, and operation across 0°C to +125°C junction temperature range.
Technical Context
This device implements a monolithic three-terminal series pass regulator architecture with integrated protection circuitry. Its internal safe-area compensated output transistor enables reliable operation under transient overload and thermal stress without external components.
The MC78M12ACDT operates as a fixed-voltage regulator with no adjustable feedback path - output voltage is set by internal resistor networks and trimmed during wafer test. Input bias current remains ≤6.0 mA across full operating conditions, supporting low-quiescent designs when paired with high-impedance sources.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 12 V nominal, ±2% accuracy at TJ = 25°C - ensures precise 12 V rail for logic and analog circuits without trimming. |
| Max Output Current | 500 mA continuous - sufficient for powering multiple ICs or small subsystems on a PCB. |
| Dropout Voltage | 2.0 V max at TJ = 25°C - requires minimum 14 V input for stable 12 V output, limiting use in ultra-low VIN applications. |
| Ripple Rejection | 55 dB min at 120 Hz, IO = 100 mA - suppresses line-frequency noise from unregulated DC supplies. |
| Thermal Shutdown | Active at TJ ≥ +150°C - prevents permanent damage during sustained overload or inadequate heatsinking. |
| Short-Circuit Limit | 350 mA typical - protects against sustained output faults while allowing brief inrush currents. |
| Operating Temp Range | 0°C to +125°C junction - suitable for commercial and extended-temperature industrial environments. |
Pinout & Package
DPAK-3 (TO-252) package with exposed thermal pad (pin 2 connected to GND). Compact surface-mount footprint (6.10 × 6.54 mm) optimized for PCB thermal conduction via copper pour under the tab.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Input | Unregulated DC input terminal; must be bypassed with ≥0.33 µF capacitor near pin for stability. |
| 2 | GND / Heatsink | Ground reference and thermal interface; electrically tied to metal tab - must connect to large GND copper area. |
| 3 | Output | Regulated 12 V output; load capacitance up to 100 µF recommended for transient response. |
Key Features
| Feature | Design Value |
|---|---|
| No external components required | Self-contained regulation with internal feedback and protection - reduces BOM count and layout complexity. |
| ±2% output accuracy (MC78MxxA grade) | Tighter tolerance than standard MC78MxxC (±4%) - improves system-level voltage margin for sensitive loads. |
| Internal thermal overload protection | Automatic shutdown above +150°C junction temperature - eliminates need for external thermal sensors or shutdown logic. |
| Safe-area compensated pass transistor | Prevents second breakdown during output short-circuit events - enhances reliability in harsh electrical environments. |
| Pb-free, RoHS-compliant packaging | DPAK-3 case 369C with "G" suffix - meets environmental compliance requirements for global industrial shipments. |
Applications
| Industrial PLC I/O Modules | Automotive Body Control Units |
|---|---|
Use Scenario: Powering digital isolators, optocouplers, and level-shifting buffers in programmable logic controller input/output cards. IC Role / Device Role / Timing Role: Local 12 V rail generator providing clean, regulated supply independent of main system bus voltage fluctuations. Use Value: ±2% output accuracy ensures consistent logic thresholds and ADC reference stability across temperature and load variations. | Use Scenario: Supplying 12 V to window lift controllers, seat position sensors, and door lock actuators in non-safety-critical vehicle subsystems. IC Role / Device Role / Timing Role: Fixed-output linear regulator delivering fault-tolerant 12 V power with built-in short-circuit and thermal protection. Use Value: Internal safe-area compensation prevents latch-up during motor stall events, improving field reliability. |
| Point-of-Load Power for MCU Peripherals | Legacy Industrial Instrumentation |
Use Scenario: Providing dedicated 12 V supply to op-amps, DACs, and communication transceivers adjacent to an ARM Cortex-M microcontroller. IC Role / Device Role / Timing Role: On-board voltage regulator minimizing noise coupling between digital and analog domains via localized regulation. Use Value: 55 dB ripple rejection at 120 Hz suppresses switching noise from upstream DC/DC converters feeding the input rail. | Use Scenario: Replacing aging 7812 regulators in legacy panel meters, data loggers, and analog signal conditioning modules requiring long-term component availability. IC Role / Device Role / Timing Role: Drop-in compatible 12 V linear regulator with identical pinout and electrical behavior to industry-standard TO-220 7812 devices. Use Value: DPAK-3 footprint offers same thermal performance as TO-220 when mounted on ≥1 oz. copper with thermal vias, enabling direct SMT replacement. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar linear voltage regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC78M12CDTRKG | ±4% output tolerance (vs. ±2% for MC78M12ACDT); otherwise identical electrical specs and package. | Suitable where tighter output accuracy is not required - e.g., non-precision analog or digital logic rails. | Select MC78M12CDTRKG for cost-sensitive designs accepting wider output variation. |
| NCV78M12BDTRKG | −40°C to +125°C operating range (vs. 0°C to +125°C); AEC-Q100 qualified; same ±4% tolerance as MC78M12CDTRKG. | Required for automotive under-hood applications or industrial systems needing extended cold-start capability. | Choose NCV78M12BDTRKG when automotive qualification or −40°C operation is mandatory. |
Compared with MC78M12CDTRKG and NCV78M12BDTRKG, the MC78M12ACDT provides superior initial accuracy (±2%) within a commercial temperature range, making it optimal for industrial control and instrumentation where precision outweighs extreme ambient requirements.
Availability
MC78M12ACDT is available at Aetrix Electronics and suitable for industrial control systems, automotive body electronics, and legacy instrumentation requiring stable component supply, long lifecycle support, and RoHS-compliant packaging.
Supply support for MC78M12ACDT 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 manufacturer specializing in energy-efficient power management, analog, sensor, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.
The MC78MxxA series was designed to deliver high-accuracy, thermally robust linear regulation for space-constrained industrial and automotive applications - extending the legacy 78xx family with tighter tolerances and modern packaging.
FAQ
What is the output voltage tolerance of the MC78M12ACDT over temperature?
The MC78M12ACDT guarantees ±2% output voltage accuracy at TJ = 25°C. Over the full 0°C to +125°C junction temperature range, output variation remains within ±4% (including line and load regulation), as specified in the MC78M12AC electrical characteristics table. This ensures predictable performance in thermally dynamic environments without external trimming.
Can the MC78M12ACDT be used without input or output capacitors?
The MC78M12ACDT does not require external capacitors for basic regulation, but onsemi recommends a ≥0.33 µF input bypass capacitor placed close to pins 1 and 2 to ensure stability under high-frequency noise or long input traces. An output capacitor (≥10 µF aluminum or 1 µF ceramic) improves transient response and reduces output impedance at higher frequencies.
What is the maximum allowable input voltage for the MC78M12ACDT?
The absolute maximum input voltage for the MC78M12ACDT is 40 Vdc, as stated in the Maximum Ratings table. However, for reliable operation with 500 mA output current, input voltage must remain ≤27 Vdc to stay within safe power dissipation limits - exceeding this risks thermal shutdown due to VI–VO × IO power loss in the pass transistor.
How does the thermal performance of the MC78M12ACDT compare between DPAK-3 and TO-220 packages?
In DPAK-3 (case 369C), the MC78M12ACDT has θJC = 5.0°C/W and θJA = 92°C/W (free air). In TO-220 (case 221AB), θJC = 5.0°C/W but θJA drops to 70°C/W - meaning the TO-220 version dissipates heat more effectively in still air. For SMT designs, DPAK-3 achieves comparable thermal resistance when mounted on ≥2 oz. copper with ≥6 thermal vias under the tab.
Is the MC78M12ACDT pin-compatible with legacy 7812 regulators?
Yes - the MC78M12ACDT uses the standard three-terminal configuration (Input, GND, Output) matching the pinout of through-hole 7812 and surface-mount 78M12 variants. Pin 1 = Input, Pin 2 = GND/Heatsink, Pin 3 = Output. This allows direct substitution in existing layouts when migrating from TO-220 to DPAK-3, provided thermal pad routing is updated per onsemi's DPAK mounting guidelines.
MC78M12ACDT 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
MC78M12ACDT FAQ
1.How can I place an order for MC78M12ACDT through Aetrix?
Please submit a Request for Quotation (RFQ) for MC78M12ACDT 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 MC78M12ACDT reliable?
The price and inventory of MC78M12ACDT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC78M12ACDT is usually 5 days.
3.What payment methods are accepted for MC78M12ACDT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC78M12ACDT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC78M12ACDT?
MC78M12ACDT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC78M12ACDT 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 MC78M12ACDT?
For technical support, including MC78M12ACDT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC78M12ACDT requirements.
6.How does Aetrix verify that MC78M12ACDT is sourced from the original manufacturer or authorized distributors?
All MC78M12ACDT 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 MC78M12ACDT meets industry standards.
7.What is the process for return or replacement of MC78M12ACDT?
All MC78M12ACDT units undergo pre-shipment inspection (PSI). If there is an issue with MC78M12ACDT, 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 MC78M12ACDT part is unused and in its original packaging.
Return procedure for MC78M12ACDT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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