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onsemi MC79M12BDT
- Part No.:
- MC79M12BDT
- Manufacturer:
- onsemi
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
MC79M12BDT.pdf
- Description:
- IC REG LINEAR -12V 500MA DPAK
- Quantity:
- Payment:
- Shipping:
Inventory:1,522
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Product details
Overview
MC79M12BDT from onsemi is a fixed-output negative voltage linear regulator delivering −12 V at up to 500 mA, featuring internal thermal shutdown, short-circuit current limiting, and safe-area compensation for rugged operation in industrial power supplies. It operates across −40 °C to +125 °C and requires no external components for basic regulation.
For engineers reviewing the MC79M12BDT datasheet, pinout, applications, or equivalent options, this page provides verified electrical specs, DPAK-3 package details, thermal performance data, and real-world use cases for negative rail generation in analog instrumentation, legacy industrial controllers, and dual-supply op-amp circuits.
Technical Context
The MC79M12BDT implements a monolithic bipolar linear regulator architecture with built-in protection circuitry: thermal overload sensing triggers automatic shutdown above +150 °C junction temperature, while current limiting activates during output short-circuit conditions. Safe-area compensation prevents secondary breakdown of the pass transistor under high-voltage/high-current stress.
It maintains regulation with input voltages as low as −14.5 V (minimum recommended) and up to −30 V (absolute max), requiring only a 1.1 V headroom (dropout) at 500 mA load. Ripple rejection exceeds 54 dB at 120 Hz, and output noise is specified at 75 µV RMS over 10 Hz–100 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | −12 V ±4% (−11.5 V to −12.5 V at 25 °C, 350 mA); stable reference for negative analog rails |
| Maximum Output Current | 500 mA continuous; limited by thermal resistance (θJA = 92 °C/W in DPAK-3) |
| Input Voltage Range | −14.5 V to −30 V (operational); −35 V absolute maximum; supports standard −15 V or −24 V input buses |
| Dropout Voltage | 1.1 V at 500 mA; defines minimum input-to-output differential needed to sustain regulation |
| Line Regulation | ≤5.0 mV (typical) over −14.5 V to −30 V input swing; ensures stable output despite input ripple or sag |
| Load Regulation | ≤240 mV (max) from 5 mA to 500 mA; critical for consistent biasing in variable-load analog stages |
| Ripple Rejection | ≥54 dB at 120 Hz; suppresses AC component from rectified transformer secondaries |
| Operating Temperature | −40 °C to +125 °C junction; qualified for industrial environments without derating below 125 °C |
Pinout & Package
DPAK-3 (Case 369C) surface-mount package: thermally enhanced plastic outline with exposed drain pad (pin 2) for PCB heat sinking. Dimensions: 6.10 × 6.54 × 2.28 mm, 2.29 mm lead pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Ground | Reference node for output voltage; must connect to common system ground plane with low impedance |
| 2 | Input | Negative input supply terminal; connects to unregulated negative source (e.g., −15 V bus) |
| 3 | Output | Regulated −12 V output; requires 1.0 µF ceramic capacitor (CO) for stability and transient response |
Key Features
| Feature | Design Value |
|---|---|
| No external components required | Enables compact, low-BOM designs-only input/output capacitors needed for basic operation |
| Internal thermal overload protection | Shuts down automatically above +150 °C junction temperature; recovers when cooled below safe threshold |
| Internal short-circuit current limiting | Clamps output current to safe level during fault; prevents damage during accidental output-to-ground shorts |
| Safe-area compensated output transistor | Prevents secondary breakdown under simultaneous high voltage and current stress (e.g., startup into heavy load) |
| Pb-free DPAK-3 packaging | RoHS-compliant surface-mount footprint with thermal pad optimized for 2 oz copper PCB heatsinking |
Applications
| Industrial Analog Signal Conditioning | Legacy Industrial Control Systems |
|---|---|
Use Scenario: Powering dual-supply operational amplifiers and precision ADC drivers in PLC I/O modules operating in harsh factory environments. IC Role / Device Role / Timing Role: Negative rail generator providing stable −12 V bias for op-amp input stages and reference buffers. Use Value: Maintains signal integrity under load transients and ambient temperature swings (−40 °C to +85 °C ambient), minimizing offset drift in 16-bit measurement circuits. |
Use Scenario: Replacing aging TO-220 regulators in retrofit upgrades of CNC machine controller boards where space is constrained. IC Role / Device Role / Timing Role: Drop-in negative voltage regulator supplying −12 V logic and interface circuitry in microcontroller-based motion control subsystems. Use Value: DPAK-3 footprint enables direct PCB replacement without layout redesign; same electrical behavior as legacy MC79M12BT but with improved thermal performance on 2 oz copper. |
| Test & Measurement Equipment | Audio Signal Processing |
Use Scenario: Generating clean negative supply for high-precision DAC output buffers and calibration reference sources in benchtop multimeters. IC Role / Device Role / Timing Role: Low-noise (75 µV RMS) negative regulator isolating sensitive analog sections from digital switching noise. Use Value: Ripple rejection >54 dB at 120 Hz suppresses transformer hum; tight output tolerance (±4%) ensures accurate full-scale voltage references. |
Use Scenario: Biasing discrete JFET-input preamplifier stages and active filters in professional audio mixing consoles. IC Role / Device Role / Timing Role: Stable −12 V rail provider enabling symmetrical clipping and wide dynamic range in analog signal paths. Use Value: Load regulation ≤240 mV ensures consistent gain and distortion performance across varying channel count loading (1–24 channels). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar negative voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM337LD-12/NOPB | −12 V adjustable variant; requires two external resistors for fixed output; higher dropout (1.5 V typ); lower max current (1.5 A) | Used where adjustable output or higher current capability is needed; less suitable for space-constrained DPAK-only layouts | Select LM337LD-12/NOPB if board already uses SOIC-8 footprints or requires programmable output via resistor network. |
| MC7912CT | TO-220-3 through-hole package; identical electrical specs; θJA = 65 °C/W (better natural convection cooling) | Preferred for prototyping, low-volume assembly, or applications requiring mechanical robustness and hand-soldering | Choose MC7912CT for manual assembly or when thermal management relies on heatsink mounting rather than PCB copper area. |
Compared with LM337LD-12/NOPB, MC79M12BDT offers simpler fixed-output implementation and smaller DPAK footprint; compared with MC7912CT, it trades easier assembly for superior PCB-level thermal integration in high-density automated production.
Availability
MC79M12BDT is available at Aetrix Electronics and suitable for industrial analog signal conditioning, legacy control system retrofits, and test equipment requiring stable component supply with long-term continuity planning.
Supply support for MC79M12BDT 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 MC79M12BDT belongs to the MC79M00 series of fixed negative voltage regulators designed specifically to complement the MC78M00 positive regulators in dual-rail power systems for industrial and instrumentation applications.
FAQ
What is the maximum input voltage rating for the MC79M12BDT?
The MC79M12BDT has an absolute maximum input voltage rating of −35 V DC. Its recommended operating input range is −14.5 V to −30 V, ensuring reliable regulation while maintaining adequate headroom for ripple and transient suppression. Exceeding −35 V risks permanent device damage per the datasheet's Maximum Ratings table.
Does the MC79M12BDT require external capacitors to function properly?
Yes, the MC79M12BDT requires both input (Cin) and output (CO) capacitors for stable operation. A 0.33 µF input capacitor is recommended if the regulator is located far from the main filter, and a 1.0 µF output capacitor improves transient response and stability. These values are specified in the Standard Application schematic on page 1 of the datasheet.
Is the MC79M12BDT RoHS compliant and lead-free?
Yes, the MC79M12BDT is a Pb-free device, indicated by the "G" suffix in its full ordering part number (e.g., MC79M12BDTRKG). Its DPAK-3 package meets RoHS Directive 2011/65/EU requirements, and the marking diagram confirms the Pb-free indicator is present per onsemi's generic marking standard.
Can the MC79M12BDT be used in place of the MC7912CT in existing designs?
The MC79M12BDT shares identical electrical specifications with the MC7912CT but uses a DPAK-3 surface-mount package instead of TO-220-3 through-hole. Direct substitution requires PCB footprint revision and requalification of thermal performance, as θJA is 92 °C/W (DPAK) versus 65 °C/W (TO-220). It is not a drop-in replacement without layout changes.
What protection features does the MC79M12BDT include?
The MC79M12BDT integrates three key protection functions: internal thermal shutdown (activates above +150 °C junction temperature), short-circuit current limiting (prevents destructive currents during output faults), and safe-area compensation (protects the output transistor from secondary breakdown under high-voltage/high-current stress).
MC79M12BDT 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:
- Negative
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- -35V
- Voltage - Output (Min/Fixed):
- -12V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 1.1V @ 500mA (Typ)
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- -
- Current - Supply (Max):
- -
- PSRR:
- 60dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DPAK
MC79M12BDT FAQ
1.How can I place an order for MC79M12BDT through Aetrix?
Please submit a Request for Quotation (RFQ) for MC79M12BDT 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 MC79M12BDT reliable?
The price and inventory of MC79M12BDT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC79M12BDT is usually 5 days.
3.What payment methods are accepted for MC79M12BDT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC79M12BDT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC79M12BDT?
MC79M12BDT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC79M12BDT 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 MC79M12BDT?
For technical support, including MC79M12BDT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC79M12BDT requirements.
6.How does Aetrix verify that MC79M12BDT is sourced from the original manufacturer or authorized distributors?
All MC79M12BDT 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 MC79M12BDT meets industry standards.
7.What is the process for return or replacement of MC79M12BDT?
All MC79M12BDT units undergo pre-shipment inspection (PSI). If there is an issue with MC79M12BDT, 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 MC79M12BDT part is unused and in its original packaging.
Return procedure for MC79M12BDT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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