MC7818ECTBU Equivalent & Substitute Parts

Part Overview

The MC7818ECTBU is a linear voltage regulator IC from onsemi, delivering a fixed positive 18V output at 1A in a TO-220-3 package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The MC7818ECTBU serves applications requiring stable 18V regulation with thermal and short-circuit protection in through-hole mounting configurations.

Substiute Parts

MC7818ECTBU

onsemiIn Stock: 741MC7818ECTBU Datasheet

Current PartRFQ

MC7818BTG

onsemiIn Stock: 17164MC7818BTG Datasheet

DirectRFQ

MC7818CTG

onsemiIn Stock: 1503MC7818CTG Datasheet

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MC78M18CTG

onsemiIn Stock: 3179MC78M18CTG Datasheet

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L7818CV-DG

STMicroelectronicsIn Stock: 65494L7818CV-DG Datasheet

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L78S18CV

STMicroelectronicsIn Stock: 2795L78S18CV Datasheet

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MC7818ACTG

onsemiIn Stock: 1773MC7818ACTG Datasheet

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MC78M18BTG

onsemiIn Stock: 5829MC78M18BTG Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MC7818ECTBU is determined by the following critical parameters:

• Output voltage: 18V fixed
• Output current capability: minimum 1A
• Input voltage rating: 35V maximum
• Package type: TO-220-3 through-hole
• Protection features: Over temperature and short circuit protection
• Output configuration: Positive fixed regulator

Substitute parts must maintain compatibility across these electrical and mechanical specifications. Parts with lower current ratings (500mA) are listed as similar but not direct equivalents due to reduced output current capacity. Parts from alternative manufacturers (STMicroelectronics) are included where electrical parameters align with the MC7818ECTBU specifications.

Parameter Comparison

Engineering Selection Recommendations

Direct Equivalent (Active Status): MC7818BTG and MC7818CTG are the primary active alternatives from onsemi. Both maintain 1A output current and 18V fixed output specifications. MC7818BTG extends the operating temperature range to -40°C, suitable for industrial applications. MC7818CTG operates within the original 0°C to 125°C range with marginally lower quiescent current. Both are ROHS3 compliant and available in active production status.

Higher Current Capability: L7818CV-DG (1.5A) and L78S18CV (2A) from STMicroelectronics provide increased output current capacity while maintaining 18V regulation. L78S18CV extends the operating temperature to 150°C and includes over-current protection. These parts are suitable for applications requiring headroom above the 1A specification.

Reduced Current Applications: MC78M18CTG and MC78M18BTG deliver 500mA output current. These are appropriate only for applications with reduced current requirements below 1A. MC78M18BTG supports -40°C to 125°C operation.

Compliance Consideration: All active and recently obsolete substitute parts carry ROHS3 compliance certification, supporting modern procurement and environmental standards.

Frequently Asked Questions (FAQ)

Q: Can MC7818CTG directly replace MC7818ECTBU? A: Yes. MC7818CTG maintains identical 1A output current, 18V fixed output, and 0°C to 125°C operating range. It is currently in active production status with ROHS3 compliance.

Q: What is the difference between MC7818BTG and MC7818CTG? A: MC7818BTG operates from -40°C to 125°C, extending low-temperature performance. MC7818CTG operates 0°C to 125°C with slightly lower quiescent current (6.5 mA vs 8 mA). Both deliver 1A output.

Q: Can I use L78S18CV as a substitute? A: L78S18CV is compatible electrically with 18V fixed output and 8 mA quiescent current. It provides 2A output current, exceeding the 1A requirement. Operating temperature extends to 150°C. This part is obsolete but available in inventory.

Q: Why are 500mA parts listed if the original is 1A? A: MC78M18CTG and MC78M18BTG are listed as similar parts but not direct equivalents due to reduced current capacity. Use only if your application requires less than 500mA output current.

Q: Are all substitute parts in the same TO-220-3 package? A: Yes. All listed parts use TO-220-3 through-hole packaging, maintaining mechanical and thermal compatibility with the original MC7818ECTBU footprint.

Q: Which substitute has the best PSRR performance? A: MC7818ECTBU specifies 69dB PSRR at 120Hz. MC78M18CTG and MC78M18BTG match this at 70dB. Other substitutes range from 43dB to 57dB.