1SMB18CAT3 Equivalent & Substitute Parts

Part Overview

The 1SMB18CAT3 is a transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface mount applications. This component features an 18V reverse standoff voltage with a 29.2V maximum clamping voltage and 20.5A peak pulse current capability in the DO-214AA (SMB) package. The part is currently classified as obsolete, making equivalent substitute parts necessary for ongoing design support and procurement.

Substiute Parts

1SMB18CAT3

onsemiIn Stock: 103571SMB18CAT3 Datasheet

Current PartRFQ

SMBJ18CA

MDDIn Stock: 143366SMBJ18CA Datasheet

DirectRFQ

SMBJ18CA

MDDIn Stock: 143366SMBJ18CA Datasheet

DirectRFQ

SMBJ18CA

MDDIn Stock: 143366SMBJ18CA Datasheet

DirectRFQ

SMBJ18CA-TR

STMicroelectronicsIn Stock: 1705SMBJ18CA-TR Datasheet

DirectRFQ

SMBJ18CA-13-F

Diodes IncorporatedIn Stock: 17481SMBJ18CA-13-F Datasheet

SimilarRFQ

SMBJ18CA-HR

Littelfuse Inc.In Stock: 710SMBJ18CA-HR Datasheet

SimilarRFQ

SMBJ18CA-HRA

Littelfuse Inc.In Stock: 1141SMBJ18CA-HRA Datasheet

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SMBJ18CA-TP

Micro Commercial CoIn Stock: 3813SMBJ18CA-TP Datasheet

SimilarRFQ

SMBJ18CAE3/TR13

Microchip TechnologyIn Stock: 1045SMBJ18CAE3/TR13 Datasheet

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SMBJ18CE3/TR13

Microchip TechnologyIn Stock: 733SMBJ18CE3/TR13 Datasheet

SimilarRFQ

TV06B180JB-G

Comchip TechnologyIn Stock: 849TV06B180JB-G Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 1SMB18CAT3 is determined by strict electrical and mechanical parameter matching within the TVS diode category. The following parameters define acceptable equivalents:

• Voltage - Reverse Standoff (Typ): 18V
• Voltage - Breakdown (Min): 20V
• Voltage - Clamping (Max) @ Ipp: 29.2V (with tolerance of ±0.3V maximum)
• Current - Peak Pulse (10/1000µs): 20.5A minimum
• Power - Peak Pulse: 600W
• Package / Case: DO-214AA, SMB
• Mounting Type: Surface Mount
• Bidirectional Channels: 1
• Type: Zener

Substitute parts are grouped into two categories: direct equivalents (identical electrical specifications) and similar parts (minor variations in peak pulse current within acceptable operating margins). All substitute parts maintain the same functional protection characteristics and package compatibility required for direct board-level replacement.

Parameter Comparison

Engineering Selection Recommendations

All listed substitute parts are active products with ROHS3 compliance, addressing the obsolescence and regulatory status of the original 1SMB18CAT3. Selection among substitutes should be based on the following criteria:

Direct Electrical Equivalents (Recommended Primary Choices):

• SMBJ18CA (MDD): Identical electrical specifications with highest inventory availability (143,300 pcs). Suitable for applications requiring standard performance characteristics.
• SMBJ18CA-13-F (Diodes Incorporated): Matches original specifications exactly with 17,400 pcs in stock. Active product status ensures long-term availability.
• SMBJ18CAE3/TR13 (Microchip): Identical electrical performance with 980 pcs available. Tape & Reel packaging suitable for automated assembly.

Alternative Selections Based on Operating Temperature:

• SMBJ18CA-TP (Micro Commercial Co): Extended upper operating temperature to 175°C with 3,800 pcs in stock. Suitable for high-temperature applications.
• SMBJ18CA-HR / SMBJ18CA-HRA (Littelfuse): Maintains -65°C lower temperature limit matching original specifications. Available in standard and tape & reel packaging.

Higher Peak Pulse Current Option:

• SMBJ18CA-TR (STMicroelectronics): 21.5A peak pulse current provides additional margin above the original 20.5A specification. Suitable for applications requiring enhanced transient protection.

All substitute parts maintain identical package geometry (DO-214AA, SMB), voltage ratings, and power dissipation characteristics, enabling direct board-level replacement without design modification.

Frequently Asked Questions (FAQ)

Q: Can I use SMBJ18CA-TR as a direct replacement for 1SMB18CAT3? A: Yes. SMBJ18CA-TR meets all electrical requirements with identical voltage ratings (18V standoff, 29.2V clamping) and exceeds the original peak pulse current specification (21.5A vs. 20.5A). The DO-214AA package is mechanically identical, enabling direct substitution.

Q: What is the difference between SMBJ18CA and SMBJ18CA-HRA? A: Both parts have identical electrical specifications. SMBJ18CA-HRA is manufactured by Littelfuse with tape & reel packaging, while SMBJ18CA is manufactured by MDD. The -HRA suffix indicates Littelfuse's high-reliability variant. Selection depends on packaging preference and supplier availability.

Q: Why is SMBJ18CE3/TR13 not recommended as a substitute? A: SMBJ18CE3/TR13 has a different clamping voltage specification (32.2V vs. 29.2V) and lower peak pulse current (18.6A vs. 20.5A). These electrical differences make it unsuitable for direct replacement in circuits designed for the 1SMB18CAT3 protection characteristics.

Q: Are all substitute parts RoHS compliant? A: Yes. All listed substitute parts are ROHS3 compliant, addressing the RoHS non-compliant status of the obsolete 1SMB18CAT3. This compliance is mandatory for new designs and procurement in regulated markets.

Q: Does operating temperature range affect substitution compatibility? A: Operating temperature range does not prevent substitution if the application operates within the substitute part's specified range. SMBJ18CA-TP offers extended upper temperature capability (-55°C to 175°C) suitable for high-temperature environments. SMBJ18CA-HR and SMBJ18CA-HRA maintain the original -65°C lower limit for low-temperature applications.

Q: What packaging options are available for automated assembly? A: SMBJ18CA-HRA, SMBJ18CA-TP, and SMBJ18CAE3/TR13 are available in tape & reel (TR) packaging suitable for pick-and-place assembly. Standard tube or bulk packaging is available for manual assembly applications.