1KSMB20 Equivalent & Substitute Parts

Part Overview

The 1KSMB20 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component features a 17.1V reverse standoff voltage with a 29.09V maximum clamping voltage and 36.1A peak pulse current capability in a DO-214AA (SMB) package. The 1KSMB20 is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain compatibility across voltage ratings, current handling, package form factor, and thermal operating ranges.

Substiute Parts

1KSMB20

Littelfuse Inc.In Stock: 10791KSMB20 Datasheet

Current PartRFQ

1KSMB20A

Taiwan Semiconductor CorporationIn Stock: 9021KSMB20A Datasheet

DirectRFQ

P6SMB20A

Eaton - Electronics DivisionIn Stock: 5158P6SMB20A Datasheet

MFR RecommendedRFQ

SZP6SMB20AT3G

Littelfuse Inc.In Stock: 5473SZP6SMB20AT3G Datasheet

MFR RecommendedRFQ

SMBJP6KE20A-TP

Micro Commercial CoIn Stock: 30145SMBJP6KE20A-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 1KSMB20 is determined by the following critical parameters:

• Voltage - Reverse Standoff (Typ): Must be 17.1V
• Voltage - Clamping (Max) @ Ipp: Must be within the range of 27.7V to 29.09V
• Current - Peak Pulse (10/1000µs): Must support minimum 21.7A (lower values acceptable for reduced power applications)
• Package / Case: Must be DO-214AA or SMB equivalent
• Mounting Type: Must be Surface Mount
• Operating Temperature Range: Must support minimum -55°C to 150°C

All substitute parts listed maintain the same unidirectional Zener diode type and general-purpose or telecom application classification. Substitutes are grouped by manufacturer and product status (Active vs. Obsolete), with preference given to active products with current inventory availability.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: 1KSMB20A (Taiwan Semiconductor Corporation)

The 1KSMB20A is the most direct electrical equivalent, maintaining identical reverse standoff voltage (17.1V), peak pulse current (36.1A), and power dissipation (1000W). This part is Active with current inventory (882 Pcs), ROHS3 compliant, and supports an extended operating temperature range (-55°C to 175°C). The slightly higher breakdown voltage minimum (19V vs. 18V) and reduced clamping voltage (27.7V vs. 29.09V) remain within acceptable substitution parameters for general-purpose TVS applications.

Secondary Substitute: SZP6SMB20AT3G (Littelfuse Inc.)

The SZP6SMB20AT3G maintains Littelfuse manufacturing continuity and is AEC-Q101 qualified for automotive applications. It provides 22A peak pulse current and 600W power dissipation with extended lower temperature capability (-65°C minimum). This part is Active with high inventory (5400 Pcs) and ROHS3 compliant. Selection of this part is appropriate for designs requiring automotive-grade qualification or extended low-temperature operation.

Tertiary Substitutes: P6SMB20A (Eaton) and SMBJP6KE20A-TP (Micro Commercial Co)

Both parts provide 22A peak pulse current and 600W power dissipation. The SMBJP6KE20A-TP offers the highest inventory availability (30100 Pcs) and extended operating temperature range (-55°C to 175°C). The P6SMB20A is suitable for telecom applications. These parts are appropriate for designs where reduced peak pulse current and power dissipation are acceptable.

Frequently Asked Questions (FAQ)

Q: Can the 1KSMB20A directly replace the 1KSMB20 in existing designs?

A: Yes. The 1KSMB20A maintains the same reverse standoff voltage (17.1V), identical peak pulse current (36.1A), and equivalent power dissipation (1000W). The clamping voltage difference (27.7V vs. 29.09V) and breakdown voltage minimum (19V vs. 18V) are within acceptable substitution parameters for general-purpose TVS applications.

Q: What is the difference between the high-current substitutes (1KSMB20A) and lower-current substitutes (P6SMB20A, SZP6SMB20AT3G, SMBJP6KE20A-TP)?

A: The 1KSMB20A supports 36.1A peak pulse current and 1000W power dissipation, matching the original 1KSMB20 specification. The alternative substitutes support 21.7A to 22A peak pulse current and 600W power dissipation. Selection depends on circuit requirements for transient energy absorption. Lower-current parts are suitable for applications with reduced overvoltage stress levels.

Q: Are all substitute parts available in the same DO-214AA SMB package?

A: Yes. All listed substitute parts use the DO-214AA (SMB) surface-mount package, ensuring mechanical and thermal compatibility with existing PCB layouts and assembly processes.

Q: Which substitute part has the best long-term availability?

A: The SMBJP6KE20A-TP (Micro Commercial Co) has the highest current inventory (30100 Pcs) and Active product status, indicating strong long-term availability. The 1KSMB20A (Taiwan Semiconductor Corporation) with 882 Pcs in stock and Active status is also a reliable choice for sustained production requirements.

Q: Does the extended operating temperature range of the 1KSMB20A affect circuit performance?

A: The 1KSMB20A supports -55°C to 175°C operation compared to the original 1KSMB20 range of -55°C to 150°C. This extended upper temperature capability provides additional thermal margin and does not negatively affect circuit performance in standard operating conditions.

Q: Is automotive qualification required for my application?

A: If your design requires automotive-grade components, the SZP6SMB20AT3G is AEC-Q101 qualified and suitable for automotive applications. Other substitutes are general-purpose or telecom-rated and do not carry automotive qualification.