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onsemi MC79M08CDT
- Part No.:
- MC79M08CDT
- Manufacturer:
- onsemi
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
MC79M08CDT.pdf
- Description:
- IC REG LINEAR -8V 500MA DPAK
- Quantity:
- Payment:
- Shipping:
Inventory:1,808
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Product details
Overview
MC79M08CDT from onsemi is a fixed-output, negative-voltage linear regulator delivering −8.0 V at up to 500 mA, featuring internal thermal shutdown, short-circuit current limiting, and safe-area compensation for rugged operation in industrial power rails. It operates across 0 °C to +125 °C, uses a DPAK-3 (Case 369C) surface-mount package, and requires no external components for basic regulation.
For engineers reviewing the MC79M08CDT datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, thermal performance data, real-world use cases, and validated alternative parts - all specific to the MC79M08CDT variant with ±4.0% output tolerance and Pb-free DPAK packaging.
Technical Context
The MC79M08CDT implements a monolithic bipolar transistor-based linear regulation architecture with integrated protection circuitry. Its dropout voltage is 1.1 V at 500 mA, and it maintains output stability with input voltages as low as −10.5 V (minimum recommended) and as high as −25 V (absolute max −35 V).
It achieves 63 dB ripple rejection at 120 Hz and exhibits 60 µV RMS output noise (10 Hz–100 kHz), with load regulation of ≤100 mV over 5–500 mA and line regulation of ≤50 mV across its specified input range. Thermal resistance is 92 °C/W (junction-to-ambient, free-air) and 6.0 °C/W (junction-to-case).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | −8.0 V nominal, ±4.0% tolerance (−7.68 V to −8.32 V), stable at 350 mA and 25 °C |
| Max Output Current | 500 mA continuous; sustained delivery requires adequate PCB copper area per thermal curves |
| Dropout Voltage | 1.1 V at 500 mA and 25 °C - defines minimum input-to-output differential needed for regulation |
| Ripple Rejection | 63 dB typical at 120 Hz - critical for suppressing AC line-derived noise in DC power supplies |
| Thermal Resistance | 92 °C/W (Junction-to-Ambient, DPAK-3, free air); drops with added copper heatsinking |
| Operating Temp Range | 0 °C to +125 °C junction temperature - suitable for commercial/industrial ambient environments |
| Protection Features | Internal thermal shutdown, short-circuit current limiting, and safe-area compensated output transistor |
Pinout & Package
DPAK-3 (Case 369C) surface-mount package: 6.10 mm × 6.54 mm × 2.28 mm body, 2.29 mm lead pitch, Pb-free, thermally enhanced single-drain tab.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Ground | Reference node for regulation; must be low-impedance connection to system ground plane |
| 2 | Input | Negative input supply terminal; accepts −10.5 V to −25 V (typical operating range) |
| 3 | Output | Regulated −8.0 V output; connects to load and output capacitor (1.0 µF recommended) |
Key Features
| Feature | Design Value |
|---|---|
| No external components required | Enables compact, low-BOM-cost power rail design without external pass transistors or compensation networks |
| Internal thermal overload protection | Shuts down output when junction temperature exceeds safe limit, preventing permanent damage during overload or poor heatsinking |
| Internal short-circuit current limiting | Clamps output current to ~500–600 mA under hard short, enabling safe fault recovery without external fusing |
| Safe-area compensated output transistor | Prevents second breakdown during transient overloads or capacitive loads, enhancing reliability in real-world conditions |
| Pb-free DPAK-3 packaging | RoHS-compliant, surface-mountable package with exposed drain tab for direct thermal coupling to PCB copper |
Applications
| Industrial Control Power Supply | Legacy Analog Instrumentation |
|---|---|
Use Scenario: Providing stable negative bias for op-amp rails and analog front-ends in PLC I/O modules and sensor signal conditioners. IC Role / Device Role / Timing Role: Negative voltage regulator supplying −8.0 V to precision amplifiers and ADC reference circuits. Use Value: Maintains ±4.0% output accuracy across 0–125 °C, minimizing offset drift and ensuring measurement repeatability. |
Use Scenario: Replacing aging discrete negative regulators in vintage test equipment and calibrated analog meters. IC Role / Device Role / Timing Role: Drop-in replacement for obsolete TO-220 negative regulators in legacy board designs. Use Value: Same −8.0 V output and protection features, but in smaller DPAK-3 footprint with improved thermal performance on modern PCBs. |
| Embedded System Auxiliary Rail | Audio Signal Processing |
Use Scenario: Generating isolated negative supply for microcontroller peripherals requiring dual-rail operation (e.g., RS-232 drivers, DAC buffers). IC Role / Device Role / Timing Role: Local negative LDO delivering clean −8.0 V to interface ICs with minimal layout impact. Use Value: 63 dB ripple rejection suppresses switching noise from adjacent DC-DC converters, reducing digital crosstalk. |
Use Scenario: Biasing operational amplifiers and active filters in professional audio mixing consoles and preamplifiers. IC Role / Device Role / Timing Role: Low-noise (60 µV RMS) negative rail generator for high-fidelity analog signal paths. Use Value: Low output noise and tight load regulation preserve dynamic range and prevent audible hum or distortion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar negative fixed-voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM337MDTX/NOPB | −1.25 V to −37 V adjustable output; requires two external resistors; 1.5 V dropout; 80 dB ripple rejection | Used where programmability or tighter ripple rejection is needed; not a drop-in replacement due to different topology and pinout | Select LM337MDTX/NOPB only if adjustable output or higher PSRR is required; MC79M08CDT offers lower BOM count and simpler layout. |
| MC79M08BDTRKG | Same −8.0 V output and DPAK-3 package, but rated for −40 °C to +125 °C extended temperature range and 4.0% tolerance | Suitable for automotive or outdoor industrial deployments where sub-zero startup is required | Choose MC79M08BDTRKG for wider temperature operation; MC79M08CDT is optimized for cost-sensitive commercial applications with 0 °C minimum ambient. |
Compared with LM337MDTX/NOPB, MC79M08CDT eliminates resistor selection and layout complexity while offering faster startup and lower quiescent current; compared with MC79M08BDTRKG, it trades extended cold-temperature capability for lower unit cost and identical electrical performance above 0 °C.
Availability
MC79M08CDT is available at Aetrix Electronics and suitable for industrial control systems, embedded instrumentation, audio signal chains, and legacy equipment repair requiring stable component supply and long-term manufacturability.
Supply support for MC79M08CDT 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 industrial, automotive, and cloud infrastructure markets.
The MC79M00 series was designed specifically to provide robust, low-cost, fixed negative voltage regulation for commercial and industrial power subsystems - complementing the MC78M00 positive regulator family with matching thermal and protection characteristics.
FAQ
What is the maximum input voltage rating for the MC79M08CDT?
The MC79M08CDT has an absolute maximum input voltage rating of −35 Vdc. However, for reliable operation within specifications, the recommended input range is −10.5 Vdc to −25 Vdc. Exceeding −35 Vdc risks permanent device damage, and operation near the absolute maximum requires careful thermal design due to increased power dissipation in the MC79M08CDT.
Does the MC79M08CDT require input and output capacitors?
Yes - a 0.33 µF input capacitor is required if the MC79M08CDT is located far from the main power supply filter, and a 1.0 µF output capacitor improves stability and transient response. These values are specified in the standard application circuit of the MC79M08CDT datasheet and help prevent oscillation and voltage overshoot during load steps.
Is the MC79M08CDT pin-compatible with TO-220 versions like MC79M08CT?
No - the MC79M08CDT uses a DPAK-3 (Case 369C) surface-mount package with pins 1=Ground, 2=Input, 3=Output, whereas MC79M08CT uses a TO-220-3 (Case 221AB) through-hole package with different pinout and mechanical dimensions. They share identical electrical functionality but are not physically interchangeable without PCB redesign.
What is the thermal performance of the MC79M08CDT in free air?
In free-air mounting, the MC79M08CDT has a junction-to-ambient thermal resistance (θJA) of 92 °C/W. This means a 1 W power dissipation will raise the junction temperature by 92 °C above ambient. For continuous 500 mA operation at −8 V output and −12 V input, power dissipation is ~2 W - requiring ≥20 mm² of 2 oz. copper pad to maintain safe junction temperature, per the MC79M08CDT thermal curve.
Can the MC79M08CDT be used in automotive applications?
The MC79M08CDT is rated for 0 °C to +125 °C operating junction temperature, making it suitable for under-hood automotive applications only if ambient temperatures remain above 0 °C and thermal design ensures junction stays within limits. For full automotive qualification including −40 °C cold-crank operation, the MC79M08BDTRKG variant is recommended instead of the MC79M08CDT.
MC79M08CDT 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):
- -8V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 1.1V @ 500mA (Typ)
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- -
- Current - Supply (Max):
- -
- PSRR:
- 63dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DPAK
MC79M08CDT FAQ
1.How can I place an order for MC79M08CDT through Aetrix?
Please submit a Request for Quotation (RFQ) for MC79M08CDT 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 MC79M08CDT reliable?
The price and inventory of MC79M08CDT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC79M08CDT is usually 5 days.
3.What payment methods are accepted for MC79M08CDT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC79M08CDT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC79M08CDT?
MC79M08CDT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC79M08CDT 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 MC79M08CDT?
For technical support, including MC79M08CDT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC79M08CDT requirements.
6.How does Aetrix verify that MC79M08CDT is sourced from the original manufacturer or authorized distributors?
All MC79M08CDT 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 MC79M08CDT meets industry standards.
7.What is the process for return or replacement of MC79M08CDT?
All MC79M08CDT units undergo pre-shipment inspection (PSI). If there is an issue with MC79M08CDT, 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 MC79M08CDT part is unused and in its original packaging.
Return procedure for MC79M08CDT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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