1SMB20CAT3G Equivalent & Substitute Parts

Part Overview

The 1SMB20CAT3G is a transient voltage suppressor (TVS) diode manufactured by Littelfuse, 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 a DO-214AA (SMB) package. The part is currently listed as obsolete, necessitating identification of active equivalent and substitute components that maintain electrical and mechanical compatibility for new designs or production continuity.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	20	V
Voltage - Breakdown (Min)	22.2	V
Voltage - Clamping (Max) @ Ipp	32.4	V
Current - Peak Pulse (10/1000µs)	18.5	A
Power - Peak Pulse	600	W
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 1SMB20CAT3G is determined by strict equivalence in the following electrical and mechanical parameters:

Voltage - Reverse Standoff (Typ): 20V
Voltage - Breakdown (Min): 22.2V
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

Substitute parts are grouped into two categories:

Direct Electrical Equivalents (20V Standoff): Parts maintaining identical voltage ratings (20V standoff, 22.2V breakdown minimum, 32.4V clamping maximum) with peak pulse current of 18.5A or greater and 600W peak pulse power in DO-214AA/SMB packaging.

Related Voltage Rating (22V Standoff): Parts with slightly elevated voltage ratings (22V standoff, 24.4V breakdown minimum, 35.5V clamping maximum) that provide higher voltage protection but remain within the same package and power class. These are suitable only when circuit design permits higher clamping voltages.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Package / Case	Operating Temperature	Product Status
1SMB20CAT3G	Littelfuse	20V	22.2V	32.4V	18.5A	600W	DO-214AA, SMB	-65°C ~ 150°C	Obsolete
SMBJ20CA	Fairchild Semiconductor	20V	22.2V	32.4V	18.6A	600W	DO-214AA, SMB	-55°C ~ 150°C	Active
SMBJ20CA-HR	Littelfuse Inc.	20V	22.2V	32.4V	18.6A	600W	DO-214AA, SMB	-65°C ~ 150°C	Active
SMBJ20CA-HRA	Littelfuse Inc.	20V	22.2V	32.4V	18.6A	600W	DO-214AA, SMB	-65°C ~ 150°C	Active
SMBJ20CA-13-F	Diodes Incorporated	20V	22.2V	32.4V	18.5A	600W	DO-214AA, SMB	-55°C ~ 150°C	Active
SMBJ20CA-E3/52	Vishay General Semiconductor - Diodes Division	20V	22.2V	32.4V	18.5A	600W	DO-214AA, SMB	-55°C ~ 150°C	Active
SMBJ20CA-TP	Micro Commercial Co	20V	22.2V	32.4V	18.5A	600W	DO-214AA, SMB	-55°C ~ 175°C	Active
TV06B200JB-G	Comchip Technology	20V	22.2V	32.4V	18.52A	600W	DO-214AA, SMB	—	Active
SMBJ22CA	MDD	22V	24.4V	35.5V	16.9A	600W	DO-214AA, SMB	-50°C ~ 150°C	Active

Engineering Selection Recommendations

Primary Substitutes (Direct Electrical Equivalents):

SMBJ20CA-HR and SMBJ20CA-HRA (Littelfuse Inc.) are the preferred direct replacements for the obsolete 1SMB20CAT3G. Both maintain identical voltage specifications (20V standoff, 22.2V breakdown, 32.4V clamping), equivalent peak pulse current (18.6A), and the full operating temperature range (-65°C ~ 150°C) of the original part. Both are ROHS3 compliant with MSL 1 (Unlimited) rating and active product status.

SMBJ20CA (Fairchild Semiconductor) provides direct electrical equivalence with 18.6A peak pulse current and 600W peak pulse power in DO-214AA/SMB packaging. Operating temperature range is -55°C ~ 150°C. This part is active and suitable for applications not requiring the extended lower temperature range of the original specification.

SMBJ20CA-13-F (Diodes Incorporated), SMBJ20CA-E3/52 (Vishay General Semiconductor - Diodes Division), and SMBJ20CA-TP (Micro Commercial Co) all maintain the 20V standoff voltage specification with 22.2V breakdown and 32.4V clamping. Peak pulse current is 18.5A, matching the original part. All are active products with ROHS3 compliance and MSL 1 rating. SMBJ20CA-TP extends the upper operating temperature to 175°C.

TV06B200JB-G (Comchip Technology) provides electrical equivalence with 18.52A peak pulse current. Operating temperature range is not specified in the provided data. This part is active and ROHS3 compliant with MSL 1 rating.

Secondary Substitute (Related Voltage Rating):

SMBJ22CA (MDD) features a 22V reverse standoff voltage with 24.4V breakdown minimum and 35.5V maximum clamping voltage. Peak pulse current is 16.9A. This part is suitable only for applications where the circuit design permits higher clamping voltages and lower peak pulse current. Operating temperature range is -50°C ~ 150°C. This part is active and ROHS3 compliant with MSL 1 rating.

Frequently Asked Questions (FAQ)

Q: Can SMBJ20CA-HR directly replace the 1SMB20CAT3G?

A: Yes. SMBJ20CA-HR maintains identical voltage ratings (20V standoff, 22.2V breakdown, 32.4V clamping), equivalent peak pulse current (18.6A), and the same operating temperature range (-65°C ~ 150°C). Both are in DO-214AA/SMB packaging. SMBJ20CA-HR is an active product from Littelfuse, the original manufacturer.

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

A: Both parts are manufactured by Littelfuse and maintain identical electrical specifications and operating temperature range. The suffix designations indicate different packaging or tape configurations. Electrical performance and compatibility are equivalent.

Q: Can I use SMBJ20CA (Fairchild) instead of the Littelfuse equivalent?

A: Yes, for applications where the operating temperature range of -55°C ~ 150°C is acceptable. SMBJ20CA maintains the same voltage ratings (20V standoff, 22.2V breakdown, 32.4V clamping) and peak pulse current (18.6A) in DO-214AA/SMB packaging. The original 1SMB20CAT3G specifies -65°C ~ 150°C; Fairchild's part does not extend to -65°C.

Q: Why is SMBJ22CA listed as a substitute if it has different voltage ratings?

A: SMBJ22CA is a related-voltage substitute suitable only when circuit design permits higher clamping voltages. It features 22V standoff (versus 20V), 24.4V breakdown minimum (versus 22.2V), and 35.5V clamping maximum (versus 32.4V). Peak pulse current is lower at 16.9A. This part is appropriate only for applications with higher voltage tolerance requirements.

Q: Are all substitute parts ROHS3 compliant?

A: All listed substitute parts are ROHS3 compliant. The original 1SMB20CAT3G is also ROHS3 compliant. All parts carry MSL 1 (Unlimited) moisture sensitivity rating.

Q: What is the difference between tape & reel and other packaging options?

A: Tape & reel (TR) packaging is standard for automated assembly processes. The electrical and mechanical specifications remain identical regardless of packaging format. Selection between packaging options depends on manufacturing process requirements, not electrical performance.

Q: Does operating temperature range affect substitution suitability?

A: Operating temperature range affects suitability based on application requirements. The original 1SMB20CAT3G specifies -65°C ~ 150°C. Substitutes with -55°C ~ 150°C range (SMBJ20CA, SMBJ20CA-13-F, SMBJ20CA-E3/52) are suitable for applications not requiring operation below -55°C. SMBJ20CA-TP extends to 175°C, providing additional high-temperature margin.

Q: Can I mix different manufacturers' parts in the same design?

A: Yes. All listed substitutes maintain the same electrical specifications (20V standoff, 22.2V breakdown, 32.4V clamping, 18.5A or greater peak pulse current) and DO-214AA/SMB packaging. Substitution between manufacturers is based on electrical and mechanical equivalence, not manufacturer preference.

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