MC7918CT Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The MC7918CT is a linear voltage regulator IC from onsemi designed for negative fixed output applications. It delivers a fixed -18V output at 1A maximum current in a TO-220-3 package configuration. The device is classified as obsolete, making identification of active equivalent parts essential for ongoing design support and procurement continuity. This reference page identifies direct substitutes that maintain electrical and mechanical compatibility while offering improved product status and compliance certifications.

Substiute Parts

MC7918CT

onsemiIn Stock: 3257MC7918CT Datasheet

Current PartRFQ

MC7918CTG

onsemiIn Stock: 2043MC7918CTG Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The MC7918CTG qualifies as a direct substitute for the MC7918CT based on the following criteria:

Electrical Equivalence: Both parts share identical output configuration (negative), output type (fixed), output voltage (-18V), maximum input voltage (-35V), output current (1A), dropout voltage (1.3V @ 1A typical), PSRR (59dB at 120Hz), and protection features (over current and over temperature).

Thermal Compatibility: Both devices operate across the same temperature range (0°C ~ 125°C).

Mechanical Compatibility: Both parts use the TO-220-3 package with through-hole mounting, ensuring direct PCB footprint compatibility.

Base Product Number: Both parts share the MC7918 base product number, confirming they are variants of the same product line.

The primary distinction is product status and compliance: MC7918CT is obsolete, while MC7918CTG is active with improved RoHS3 compliance.

Parameter Comparison

Engineering Selection Recommendations

For New Designs: MC7918CTG is the appropriate selection. It maintains full electrical and mechanical compatibility with MC7918CT while offering active product status and ROHS3 compliance certification.

For Legacy System Support: MC7918CT remains functionally equivalent to MC7918CTG for applications where existing inventory is available. However, procurement of MC7918CT is constrained by its obsolete status.

Compliance Considerations: MC7918CTG carries ROHS3 compliance and REACH unaffected status, meeting modern regulatory requirements. MC7918CT is RoHS non-compliant and should be evaluated against applicable environmental regulations in target markets.

Frequently Asked Questions (FAQ)

Q: Can MC7918CTG replace MC7918CT in existing designs? A: Yes. MC7918CTG is a direct electrical and mechanical substitute. Both devices deliver -18V at 1A with identical dropout voltage, PSRR, protection features, and thermal operating range. The TO-220-3 package footprint is identical, requiring no PCB modifications.

Q: What is the primary reason to transition from MC7918CT to MC7918CTG? A: MC7918CT is obsolete, limiting long-term procurement availability. MC7918CTG is an active product from the same manufacturer with identical electrical specifications and improved RoHS3 compliance.

Q: Are there packaging differences between these parts? A: MC7918CTG is supplied in tube packaging, while MC7918CT packaging is not specified. Both use the TO-220-3 case style for through-hole mounting.

Q: Do these parts have identical thermal and electrical performance? A: Yes. Both parts operate across 0°C to 125°C, deliver 1A output current, maintain 1.3V typical dropout voltage at rated current, and provide 59dB PSRR at 120Hz with identical over current and over temperature protection.

Q: What certifications apply to MC7918CTG? A: MC7918CTG is ROHS3 compliant and REACH unaffected. MC7918CT is RoHS non-compliant.