MC79M12CTG Linear Voltage Regulator - Equivalent & Substitute Parts

Part Overview

The MC79M12CTG is a linear voltage regulator IC manufactured by onsemi, designed to provide a fixed negative output of -12V at 500mA in a TO-220-3 package. This component is classified as obsolete, which necessitates identification of active equivalent and substitute parts for new designs and ongoing production requirements. The part operates across an input voltage range up to -35V and includes integrated over-current and over-temperature protection features.

Substiute Parts

MC79M12CTG

onsemiIn Stock: 1211MC79M12CTG Datasheet

Current PartRFQ

L7912ACV

STMicroelectronicsIn Stock: 25408L7912ACV Datasheet

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L7912CV

STMicroelectronicsIn Stock: 75321L7912CV Datasheet

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LM7912CT/NOPB

Texas InstrumentsIn Stock: 2879LM7912CT/NOPB Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the MC79M12CTG is determined by the following critical parameters:

• Output Voltage: All substitute parts must provide a fixed -12V output
• Package / Case: All substitute parts must use TO-220-3 package for direct pin compatibility
• Mounting Type: Through-hole mounting must be maintained
• Input Voltage Rating: Maximum input voltage of -35V or greater
• Operating Temperature Range: 0°C ~ 125°C minimum
• Compliance: ROHS3 compliance required

The substitute parts identified (L7912ACV, L7912CV, and LM7912CT/NOPB) meet all these criteria. These parts provide equal or higher output current capability (1.5A versus 500mA), ensuring functional compatibility in applications designed for the MC79M12CTG.

Parameter Comparison

Engineering Selection Recommendations

All three substitute parts are classified as active products with current manufacturing support, providing long-term availability advantages over the obsolete MC79M12CTG. Each substitute maintains full electrical and mechanical compatibility with the original part through identical TO-220-3 packaging and pin configuration.

The L7912CV and L7912ACV from STMicroelectronics offer equivalent specifications with higher output current capability (1.5A). The L7912CV demonstrates the highest inventory availability (75,300 units), supporting immediate procurement needs.

The LM7912CT/NOPB from Texas Instruments provides superior PSRR performance (70dB versus 60dB at 120Hz) and lower quiescent current (1.5mA versus 3mA), offering enhanced noise rejection characteristics for noise-sensitive applications.

All substitute parts maintain ROHS3 compliance and unlimited moisture sensitivity level (MSL 1), ensuring compatibility with standard manufacturing and storage requirements.

Frequently Asked Questions (FAQ)

Q: Can the MC79M12CTG be directly replaced with any of the substitute parts?

A: Yes. All substitute parts share identical TO-220-3 package geometry, pin configuration, and electrical output specifications (-12V fixed output). Direct pin-for-pin substitution is supported without circuit modification.

Q: Why do the substitute parts have higher output current ratings (1.5A) than the original (500mA)?

A: Higher current capability does not affect compatibility. A 1.5A-rated regulator operates identically to a 500mA-rated regulator in circuits designed for 500mA or less. The higher rating provides design margin and supports potential future current requirements.

Q: Are there differences in thermal or noise performance between the substitutes?

A: The LM7912CT/NOPB provides superior PSRR (70dB versus 60dB), resulting in better noise rejection at 120Hz. The LM7912CT/NOPB also features lower quiescent current (1.5mA versus 3mA), reducing standby power consumption. Both factors may benefit noise-sensitive or low-power applications.

Q: Which substitute part should be selected for new designs?

A: Selection depends on application requirements and supply chain considerations. The L7912CV offers the highest inventory availability. The LM7912CT/NOPB is recommended for applications requiring superior noise performance or lower quiescent current. All three parts are active products with established manufacturing support.

Q: Do all substitute parts meet the same compliance requirements?

A: Yes. All substitute parts are ROHS3 compliant, REACH unaffected, and classified as MSL 1 (unlimited moisture sensitivity). Compliance certifications are equivalent across all options.