1KSMBJ27A Equivalent & Substitute Parts

Part Overview

The 1KSMBJ27A is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for telecom applications. It features a 23.1V reverse standoff voltage with 37.5V maximum clamping voltage and 26.7A peak pulse current in a surface mount DO-214AA (SMB) package. The part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility for continued system support and new designs.

Substiute Parts

1KSMBJ27A

Littelfuse Inc.In Stock: 8671KSMBJ27A Datasheet

Current PartRFQ

1KSMB27A

Taiwan Semiconductor CorporationIn Stock: 12281KSMB27A Datasheet

DirectRFQ

SZP6SMB27AT3G

onsemiIn Stock: 2160SZP6SMB27AT3G Datasheet

MFR RecommendedRFQ

SM6T27A

STMicroelectronicsIn Stock: 10481SM6T27A Datasheet

MFR RecommendedRFQ

SM6T27AY

STMicroelectronicsIn Stock: 7176SM6T27AY Datasheet

MFR RecommendedRFQ

SMBJP6KE27A-TP

Micro Commercial CoIn Stock: 1190SMBJP6KE27A-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 1KSMBJ27A is determined by the following critical parameters:

• Voltage Rating Match: Reverse standoff voltage of 23.1V and breakdown voltage minimum of 25.7V must be maintained
• Clamping Voltage: Maximum clamping voltage at Ipp must not exceed 37.5V to ensure circuit protection integrity
• Peak Pulse Current: Minimum 26.7A at 10/1000µs pulse profile to handle transient events
• Package Compatibility: DO-214AA (SMB) surface mount package required for PCB layout compatibility
• Diode Type: Unidirectional Zener configuration with single channel
• Temperature Range: Operating temperature capability must support -55°C to 150°C minimum

The substitute parts are grouped into two categories based on electrical performance alignment:

Category A - Direct Electrical Equivalents (37.5V Clamping): Parts maintaining the exact 37.5V clamping voltage specification with comparable peak pulse current ratings.

Category B - Higher Performance Alternatives (48.3V Clamping): Parts with elevated clamping voltage that provide enhanced transient suppression capability while maintaining voltage standoff compatibility.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation - 1KSMB27A (Taiwan Semiconductor Corporation)

The 1KSMB27A is the closest functional equivalent to the obsolete 1KSMBJ27A. It maintains identical voltage ratings (23.1V standoff, 25.7V breakdown, 37.5V clamping) and peak pulse current (26.7A), with matching 1000W peak pulse power rating. The part is in active production status with ROHS3 compliance and unlimited moisture sensitivity rating. Extended operating temperature range (-55 to 175°C) provides additional thermal margin. Packaging is Tape & Reel format with 1212 units in stock.

Secondary Recommendation - SMBJP6KE27A-TP (Micro Commercial Co)

This part maintains the 37.5V clamping voltage and 23.1V standoff specification with active product status. Peak pulse current is rated at 16.3A, which is lower than the original 26.7A specification but remains within the same voltage protection class. Extended temperature range (-55 to 175°C) and ROHS3 compliance are provided. Suitable for applications where peak pulse current requirements are less stringent than the original design.

Alternative for Enhanced Performance - SM6T27A or SM6T27AY (STMicroelectronics)

These parts offer elevated clamping voltage (48.3V) with significantly higher peak pulse current capability (83A at 8/20µs pulse profile). Both maintain the 23.1V standoff and 25.7V breakdown specifications. SM6T27AY includes automotive-grade qualification (AEC-Q101) for applications requiring automotive reliability standards. These alternatives provide superior transient suppression performance while maintaining voltage compatibility.

Automotive Applications - SZP6SMB27AT3G (onsemi) or SM6T27AY (STMicroelectronics)

For automotive or mission-critical applications, SZP6SMB27AT3G and SM6T27AY both carry AEC-Q101 qualification. SZP6SMB27AT3G maintains 37.5V clamping with 16A peak pulse current and extended temperature range (-65 to 150°C). SM6T27AY provides higher performance with 48.3V clamping and 83A peak pulse current, also AEC-Q101 qualified.

Frequently Asked Questions (FAQ)

Q: Can I use SM6T27A or SM6T27AY as direct replacements for 1KSMBJ27A?

A: These parts are electrically compatible for voltage protection but have different performance characteristics. The 48.3V clamping voltage is higher than the original 37.5V specification, and peak pulse current is rated at 83A (8/20µs pulse) versus 26.7A (10/1000µs pulse). They maintain the same 23.1V standoff voltage and DO-214AA package. Use these only if your circuit design can accommodate the higher clamping voltage and different pulse profile.

Q: What is the difference between the 10/1000µs and 8/20µs pulse specifications?

A: These represent different transient event profiles. The 10/1000µs profile (used by 1KSMBJ27A and most direct equivalents) simulates slower transient events, while 8/20µs (used by SM6T27A and SM6T27AY) represents faster transient events. Peak current ratings differ between these profiles. Verify your application's transient event characteristics before selecting a substitute.

Q: Is 1KSMB27A a true equivalent to 1KSMBJ27A?

A: Yes. The 1KSMB27A matches all critical electrical parameters: 23.1V standoff voltage, 25.7V breakdown minimum, 37.5V clamping maximum, and 26.7A peak pulse current. Both use DO-214AA (SMB) surface mount packaging. The primary difference is manufacturer (Taiwan Semiconductor vs. Littelfuse) and product status (active vs. obsolete). Packaging format differs slightly (SMB vs. SMBJ designation), but both are DO-214AA compatible.

Q: Why do some substitutes have lower peak pulse current ratings?

A: SMBJP6KE27A-TP (16.3A) and SZP6SMB27AT3G (16A) have lower peak pulse current ratings than the original 26.7A specification. These parts still provide voltage clamping at the same 37.5V level but with reduced current handling capacity. They are suitable for applications with lower transient current requirements. Verify your circuit's peak transient current demands before selecting these alternatives.

Q: Are all substitute parts RoHS3 compliant?

A: Most substitutes are ROHS3 compliant (1KSMB27A, SMBJP6KE27A-TP, SM6T27A, SM6T27AY). SZP6SMB27AT3G does not list RoHS status in the provided specifications. Verify RoHS compliance requirements for your application before final part selection.

Q: Which substitute is best for automotive applications?

A: SM6T27AY and SZP6SMB27AT3G both carry AEC-Q101 automotive qualification. SM6T27AY provides higher performance (83A peak pulse, 48.3V clamping) with automotive-grade reliability. SZP6SMB27AT3G maintains the original 37.5V clamping voltage with 16A peak pulse current and extended temperature range (-65 to 150°C). Select based on your specific transient current and voltage requirements.

Q: Can I substitute parts with different operating temperature ranges?

A: Yes, if the substitute's temperature range meets or exceeds your application requirements. The original 1KSMBJ27A operates -55 to 150°C. Substitutes like 1KSMB27A and SMBJP6KE27A-TP extend to -55 to 175°C, providing additional thermal margin. SZP6SMB27AT3G extends the lower limit to -65°C. Verify your system's thermal environment before selecting a part with a narrower temperature range.