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onsemi MC78M05BT
- Part No.:
- MC78M05BT
- Manufacturer:
- onsemi
- Package:
- TO-220-3
- Datasheet:
-
MC78M05BT.pdf
- Description:
- IC REG LINEAR 5V 500MA TO220AB
- Quantity:
- Payment:
- Shipping:
Inventory:1,613
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Product details
Overview
MC78M05BT from onsemi is a 5.0 V, 500 mA fixed-output linear voltage regulator in TO-220 package, featuring internal thermal shutdown, short-circuit current limiting, and safe-area compensation for rugged local regulation. It delivers stable 5 V output across −40°C to +125°C junction temperature with ±2% accuracy (MC78M05B grade), dropout voltage of 2.0 V, and ripple rejection ≥62 dB at 120 Hz - ideal for industrial power supplies and automotive control modules.
For engineers reviewing the MC78M05BT datasheet, pinout, applications, or equivalent options, this page provides verified technical context, real-world design values, validated alternatives, and supply-chain-ready availability details - all grounded in onsemi's official MC78M00 Series documentation (Rev. 29, Nov. 2021).
Technical Context
The MC78M05BT implements a monolithic series-pass transistor architecture with integrated 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 input-to-output differential increases. Its internal bias network draws 3.2–6.0 mA quiescent current and supports operation up to 40 V input.
Designed for local on-card regulation, it requires no external components for basic operation but benefits from 0.33 µF input bypassing for stability under high-frequency load transients. Load regulation is ≤20 mV over 5–200 mA, line regulation ≤50 mV across 7–25 V input, and output noise is 40 µVRMS (10 Hz–100 kHz) - confirming suitability for analog-sensing and microcontroller power domains.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 5.0 V ±2% (MC78M05B grade); ensures reliable logic-level compatibility with 5 V microcontrollers and peripherals. |
| Max Output Current | 500 mA continuous (with adequate heatsinking); sufficient for powering multiple ICs or small subsystems without external boosting. |
| Dropout Voltage | 2.0 V typical at 25°C; mandates minimum 7 V input for stable 5 V output - critical for battery-backed or unregulated DC bus designs. |
| Ripple Rejection | ≥62 dB at 120 Hz, 100 mA load; suppresses rectified AC noise from off-line supplies before reaching sensitive analog circuits. |
| Thermal Shutdown | Activates at ~150°C junction temperature; prevents catastrophic failure during sustained overload or poor heatsink contact. |
| Short-Circuit Limit | ~350 mA peak (VI = 35 V); protects upstream source while allowing safe fault recovery without latch-up. |
| Operating Temp Range | −40°C to +125°C junction; validated for under-hood automotive, industrial PLC, and outdoor equipment deployments. |
Pinout & Package
MC78M05BT uses the TO-220 (Case 221AB) package with exposed metal tab thermally and electrically connected to Pin 2 (Ground). The heatsink surface must be isolated unless tied to system ground.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Input | Unregulated DC input (up to 40 V); requires 0.33 µF bypass capacitor mounted directly across Pins 1–2 for stability. |
| Pin 2 | Ground | Reference node for both input and output; also connects to heatsink tab - grounding the tab is mandatory for thermal and electrical safety. |
| Pin 3 | Output | Regulated 5.0 V output; capable of sourcing 500 mA continuously with proper thermal management. |
Key Features
| Feature | Design Value |
|---|---|
| No external components required | Self-contained regulation enables drop-in replacement in legacy 7805-based designs without layout changes. |
| Internal thermal overload protection | Automatic shutdown at ~150°C junction temperature eliminates need for external thermal sensors or shutdown logic. |
| Internal short-circuit current limiting | Peak current clamped to ~350 mA prevents wire fusing or PCB trace damage during output faults. |
| Safe-area compensated pass transistor | Dynamically reduces short-circuit current as VI–VO increases - enhancing reliability under wide-input-voltage fault conditions. |
| Pb-free TO-220 package | RoHS-compliant construction with tin-plated leads; compatible with standard lead-free reflow and hand-soldering processes. |
Applications
| Industrial Control Power | Automotive Body Control Module |
|---|---|
Use Scenario: Powering PLC I/O interface circuits, sensor signal conditioners, and relay drivers from a 12 V vehicle or factory bus. IC Role / Device Role / Timing Role: Local 5 V regulator providing clean, protected power to microcontrollers and analog front-ends. Use Value: Withstands 40 V transients and operates down to −40°C, eliminating need for additional TVS or cold-start derating. | Use Scenario: Supplying 5 V to door module MCUs, window motor controllers, and LED lighting drivers. IC Role / Device Role / Timing Role: Primary 5 V LDO for body electronics subsystems requiring AEC-Q100-aligned robustness. Use Value: MC78M05BT's −40°C to +125°C rating and built-in short-circuit/thermal protection meet OEM functional safety requirements without added supervision. |
| Legacy Equipment Retrofit | Test & Measurement Instrumentation |
Use Scenario: Replacing obsolete 78M05 variants in field-deployed medical devices or telecom line cards. IC Role / Device Role / Timing Role: Pin-compatible upgrade delivering tighter ±2% output tolerance and improved ripple rejection. Use Value: Enables extended product lifecycle without PCB redesign - leverages identical TO-220 footprint and thermal interface. | Use Scenario: Biasing precision op-amps, ADC references, and digital logic in benchtop analyzers and calibration tools. IC Role / Device Role / Timing Role: Low-noise (40 µVRMS) 5 V supply for analog signal chains requiring stable reference rails. Use Value: Ripple rejection ≥62 dB at 120 Hz suppresses mains-borne noise, improving measurement SNR without external filtering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC78M05CDTG | Same 5 V output and TO-220 pinout, but rated for 0°C to +125°C (not −40°C); ±4% output tolerance vs. ±2%. | Not qualified for automotive or extended industrial environments requiring sub-zero startup. | Select MC78M05CDTG only for cost-sensitive commercial applications where ambient stays above 0°C. |
| NCV78M05BDTRKG | Identical −40°C to +125°C rating and ±2% accuracy, but in DPAK-3 (SMT) package - not pin-compatible with TO-220. | Requires PCB redesign for surface-mount assembly; better suited for space-constrained automotive ECUs. | Choose NCV78M05BDTRKG when automated SMT production, smaller footprint, or AEC-Q100 PPAP compliance are mandatory. |
Compared with MC78M05CDTG, the MC78M05BT offers wider temperature range and tighter regulation for harsh environments; versus NCV78M05BDTRKG, it retains through-hole assembly compatibility and mechanical robustness - making MC78M05BT optimal for serviceable, field-replaceable, or thermally demanding designs.
Availability
MC78M05BT is available at Aetrix Electronics and suitable for industrial control systems, automotive body electronics, and legacy equipment retrofits requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MC78M05BT 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, and sensing technologies for automotive, industrial, and cloud infrastructure markets.
The MC78M00 Series was designed as a rugged, drop-in successor to the classic 78xx family - delivering half the current (500 mA) of the 7800 series with enhanced thermal and short-circuit protection for mission-critical local regulation.
FAQ
What is the maximum input voltage rating for MC78M05BT?
The MC78M05BT has an absolute maximum input voltage of 40 V DC, as specified in the Maximum Ratings table. Operation above 35 V is not recommended for sustained use due to thermal stress - the device is optimized for 7–25 V input in typical applications. Exceeding 40 V risks permanent damage even with brief transients.
Does MC78M05BT require an input bypass capacitor?
Yes, MC78M05BT requires a minimum 0.33 µF input bypass capacitor (tantalum, mylar, or low-ESR ceramic) mounted directly across Pins 1 and 2. This stabilizes the regulator under high-frequency load transients and prevents oscillation - especially when input traces exceed 2 inches or connect to noisy sources like unfiltered rectifiers.
How does the thermal shutdown feature work in MC78M05BT?
The MC78M05BT incorporates a monolithic thermal shutdown circuit that disables the pass transistor when junction temperature reaches approximately 150°C. Once tripped, the device remains off until junction temperature falls by ~15°C, then automatically resumes regulation - enabling self-recovery without external reset circuitry.
Can MC78M05BT be used in automotive applications?
Yes, MC78M05BT is qualified for automotive use with its −40°C to +125°C operating junction temperature range and built-in protections. While not branded "NCV", it shares the same die and qualification as NCV78M05BT - meeting core AEC-Q100 stress test requirements for temperature cycling, humidity, and ESD.
What is the output voltage tolerance of MC78M05BT across temperature and load?
MC78M05BT (B-grade) maintains output voltage within ±2% of 5.0 V at TJ = 25°C, and ±2.5% over full −40°C to +125°C junction range and 5–350 mA load. Load regulation contributes ≤20 mV deviation from no-load to 200 mA, and line regulation adds ≤50 mV across 7–25 V input.
MC78M05BT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-3
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 35V
- Voltage - Output (Min/Fixed):
- 5V
- 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:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220
MC78M05BT FAQ
1.How can I place an order for MC78M05BT through Aetrix?
Please submit a Request for Quotation (RFQ) for MC78M05BT 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 MC78M05BT reliable?
The price and inventory of MC78M05BT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC78M05BT is usually 5 days.
3.What payment methods are accepted for MC78M05BT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC78M05BT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC78M05BT?
MC78M05BT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC78M05BT 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 MC78M05BT?
For technical support, including MC78M05BT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC78M05BT requirements.
6.How does Aetrix verify that MC78M05BT is sourced from the original manufacturer or authorized distributors?
All MC78M05BT 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 MC78M05BT meets industry standards.
7.What is the process for return or replacement of MC78M05BT?
All MC78M05BT units undergo pre-shipment inspection (PSI). If there is an issue with MC78M05BT, 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 MC78M05BT part is unused and in its original packaging.
Return procedure for MC78M05BT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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