1SMB20CAT3 Equivalent & Substitute Parts

Part Overview

The 1SMB20CAT3 is a transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface mount applications. This component features a 20V reverse standoff voltage with a 32.4V maximum clamping voltage and 18.5A peak pulse current capability in the DO-214AA (SMB) package. The part is currently classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production support.

Key Parameters

Parameter	Value
Voltage - Reverse Standoff (Typ)	20V
Voltage - Breakdown (Min)	22.2V
Voltage - Clamping (Max) @ Ipp	32.4V
Current - Peak Pulse (10/1000µs)	18.5A
Power - Peak Pulse	600W
Package / Case	DO-214AA, SMB
Mounting Type	Surface Mount
Operating Temperature Range	-65°C ~ 150°C (TJ)
Type	Zener
Bidirectional Channels	1

Substitute Part Grouping Explanation

Substitution of the 1SMB20CAT3 is determined by strict electrical and mechanical parameter matching:

Critical Matching Parameters:

Voltage - Reverse Standoff: 20V (±tolerance)
Voltage - Clamping (Max) @ Ipp: 32.4V
Current - Peak Pulse (10/1000µs): 18.5A minimum
Power - Peak Pulse: 600W
Package / Case: DO-214AA, SMB
Mounting Type: Surface Mount
Bidirectional Channels: 1
Type: Zener

All substitute parts listed maintain these electrical specifications within acceptable engineering tolerances. Peak pulse current values ranging from 18.5A to 19.4A are acceptable as they meet or exceed the original specification. Operating temperature ranges may vary between -55°C and -65°C minimum, with all parts supporting the 150°C maximum requirement.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Voltage - Reverse Standoff	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse	Power - Peak Pulse	Package	Product Status	Operating Temp (Min)
1SMB20CAT3	onsemi	20V	32.4V	18.5A	600W	DO-214AA, SMB	Obsolete	-65°C
SMBJ20CA	Fairchild Semiconductor	20V	32.4V	18.6A	600W	DO-214AA, SMB	Active	-55°C
SMBJ20CA-TR	STMicroelectronics	20V	32.4V	19.4A	600W	DO-214AA, SMB	Active	-55°C
SMBJ20CA/54	Vishay General Semiconductor - Diodes Division	20V	32.4V	18.5A	600W	DO-214AA, SMB	Active	-55°C
SMBJ20CA-13-F	Diodes Incorporated	20V	32.4V	18.5A	600W	DO-214AA, SMB	Active	-55°C
SMBJ20CA-HR	Littelfuse Inc.	20V	32.4V	18.6A	600W	DO-214AA, SMB	Active	-65°C
SMBJ20CA-HRA	Littelfuse Inc.	20V	32.4V	18.6A	600W	DO-214AA, SMB	Active	-65°C
SMBJ20CA-M3/52	Vishay General Semiconductor - Diodes Division	20V	32.4V	18.5A	600W	DO-214AA, SMB	Active	-55°C
SMBJ20CA-TP	Micro Commercial Co	20V	32.4V	18.5A	600W	DO-214AA, SMB	Active	-55°C

Engineering Selection Recommendations

All listed substitute parts are electrically and mechanically compatible with the 1SMB20CAT3 based on matching critical parameters. Selection should prioritize active product status parts for long-term availability and supply chain stability.

Compliance Considerations:

SMBJ20CA-TR (STMicroelectronics), SMBJ20CA-13-F (Diodes Incorporated), SMBJ20CA-M3/52 (Vishay), and SMBJ20CA-TP (Micro Commercial Co) are RoHS3 compliant, meeting modern environmental and regulatory requirements. SMBJ20CA-HR and SMBJ20CA-HRA (Littelfuse) offer extended temperature range support (-65°C minimum), matching the original 1SMB20CAT3 specification.

For applications requiring the lowest operating temperature specification, SMBJ20CA-HR, SMBJ20CA-HRA, and the original 1SMB20CAT3 support -65°C. All other active substitutes operate to -55°C minimum, which is acceptable for most general-purpose applications.

Frequently Asked Questions (FAQ)

Q: Can I use SMBJ20CA-TR as a direct replacement for 1SMB20CAT3?

A: Yes. SMBJ20CA-TR meets all critical electrical parameters: 20V reverse standoff, 32.4V clamping voltage, 19.4A peak pulse current, and 600W peak power in the DO-214AA SMB package. The part is active and RoHS3 compliant.

Q: What is the difference between SMBJ20CA-HR and SMBJ20CA-HRA?

A: Both parts are manufactured by Littelfuse and share identical electrical specifications and operating temperature range (-65°C to 150°C). The suffix designations indicate different packaging or tape configurations. Electrical performance is equivalent.

Q: Does the peak pulse current variation (18.5A to 19.4A) affect compatibility?

A: No. All substitute parts meet or exceed the original 18.5A specification. Variations within this range are within normal manufacturing tolerances and do not affect circuit protection performance.

Q: Are there packaging differences between substitute parts?

A: All substitute parts use the DO-214AA (SMB) surface mount package. Some variants include different tape and reel configurations (TR, CT) or suffix codes indicating packaging options, but the physical component package remains identical.

Q: Which substitute offers the best long-term availability?

A: SMBJ20CA-13-F (Diodes Incorporated) has the highest inventory level at 65,200 pieces. SMBJ20CA-TR (STMicroelectronics) with 6,626 pieces and SMBJ20CA-TP (Micro Commercial Co) with 3,484 pieces also provide strong availability. All three are active products with RoHS3 compliance.

Q: Can I use a substitute with -55°C minimum temperature if my application requires -65°C?

A: No. If your circuit operates at or below -55°C, use SMBJ20CA-HR, SMBJ20CA-HRA, or the original 1SMB20CAT3 to ensure specified performance across the full operating range.

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