1SMB33CAT3 Equivalent & Substitute Parts

Part Overview

The 1SMB33CAT3 is a transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface mount applications. This component features a 33V reverse standoff voltage with a 53.3V maximum clamping voltage and 11.3A peak pulse current capability in the DO-214AA (SMB) package format. The part is currently classified as obsolete, making identification of active equivalent and substitute components essential for ongoing design support and procurement.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	33	V
Voltage - Breakdown (Min)	36.7	V
Voltage - Clamping (Max) @ Ipp	53.3	V
Current - Peak Pulse (10/1000µs)	11.3	A
Power - Peak Pulse	600	W
Bidirectional Channels	1	—
Package / Case	DO-214AA, SMB	—
Mounting Type	Surface Mount	—
Operating Temperature Range	-65 to 150	°C (TJ)
Applications	General Purpose	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the 1SMB33CAT3 is determined by strict equivalence across the following electrical and mechanical parameters:

Voltage - Reverse Standoff (Typ): 33V
Voltage - Breakdown (Min): 36.7V
Voltage - Clamping (Max) @ Ipp: 53.3V
Current - Peak Pulse (10/1000µs): 11.3A (or higher)
Power - Peak Pulse: 600W
Package / Case: DO-214AA, SMB
Bidirectional Channels: 1
Mounting Type: Surface Mount
Moisture Sensitivity Level (MSL): 1 (Unlimited)

Substitute parts are classified into two categories:

Direct Equivalents: Parts meeting all electrical specifications with identical voltage and current ratings. These include SMBJ33CA (MDD), SMBJ33CA-13-F (Diodes Incorporated), SMBJ33CA-HR (Littelfuse Inc.), SMBJ33CA-HRA (Littelfuse Inc.), SMBJ33CA-M3/52 (Vishay), SMBJ33CA-M3/5B (Vishay), and SMBJ33CA-TP (Micro Commercial Co).

Similar Equivalents: Parts with marginally higher peak pulse current (11.8A) or extended operating temperature ranges that maintain functional compatibility. SMBJ33CA-TR (STMicroelectronics) falls into this category with 11.8A peak pulse current.

All substitute parts maintain the same DO-214AA (SMB) package format, surface mount configuration, and MSL rating, ensuring mechanical and thermal compatibility with the original design.

Parameter Comparison

Parameter	1SMB33CAT3 (onsemi)	SMBJ33CA (MDD)	SMBJ33CA-13-F (Diodes Inc.)	SMBJ33CA-HR (Littelfuse)	SMBJ33CA-HRA (Littelfuse)	SMBJ33CA-M3/52 (Vishay)	SMBJ33CA-M3/5B (Vishay)	SMBJ33CA-TP (MCC)	SMBJ33CA-TR (STMicro)
Voltage - Reverse Standoff (Typ)	33V	33V	33V	33V	33V	33V	33V	33V	33V
Voltage - Breakdown (Min)	36.7V	36.7V	36.7V	36.7V	36.7V	36.7V	36.7V	36.7V	36.7V
Voltage - Clamping (Max) @ Ipp	53.3V	53.3V	53.3V	53.3V	53.3V	53.3V	53.3V	53.3V	53.3V
Current - Peak Pulse (10/1000µs)	11.3A	11.3A	11.3A	11.3A	11.3A	11.3A	11.3A	11.3A	11.8A
Power - Peak Pulse	600W	600W	600W	600W	600W	600W	600W	600W	600W
Operating Temperature Range	-65 to 150°C	-50 to 150°C	-55 to 150°C	-65 to 150°C	-65 to 150°C	-55 to 150°C	-55 to 150°C	-55 to 175°C	-55 to 150°C
Package / Case	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

All listed substitute parts are classified as active products with current manufacturing support, addressing the obsolescence status of the 1SMB33CAT3. Selection among equivalents should be based on the following criteria:

RoHS Compliance: All substitute parts are ROHS3 compliant, whereas the original 1SMB33CAT3 is RoHS non-compliant. This compliance status is mandatory for applications subject to environmental regulations.

Product Status and Availability: All substitute parts maintain active product status with confirmed inventory levels ranging from 775 to 35,300 units, ensuring long-term procurement viability.

Temperature Range Considerations: The SMBJ33CA-TP (Micro Commercial Co) offers an extended upper operating temperature limit of 175°C compared to the standard 150°C maximum, providing additional thermal margin for high-temperature applications. The SMBJ33CA (MDD) operates at a reduced lower temperature limit of -50°C versus -65°C for other options.

Peak Pulse Current: The SMBJ33CA-TR (STMicroelectronics) provides 11.8A peak pulse current, exceeding the 11.3A specification of the original part, offering enhanced transient protection capability.

Manufacturer Selection: Established manufacturers including Littelfuse Inc., Vishay General Semiconductor, Diodes Incorporated, STMicroelectronics, and Micro Commercial Co provide multiple sourcing options to mitigate supply chain risk.

Frequently Asked Questions (FAQ)

Q: Can I directly replace the 1SMB33CAT3 with any of the listed substitute parts?

A: Yes. All listed substitute parts maintain identical electrical specifications (33V standoff, 36.7V breakdown minimum, 53.3V clamping maximum, 11.3A peak pulse current, 600W peak power) and the same DO-214AA (SMB) package format. Direct PCB-level substitution is mechanically and electrically compatible.

Q: What is the significance of the RoHS compliance difference?

A: The original 1SMB33CAT3 is RoHS non-compliant, while all substitute parts are ROHS3 compliant. For applications subject to RoHS directives or customer requirements, substitute parts must be used. RoHS3 compliance indicates the absence of restricted substances (lead, cadmium, hexavalent chromium, polybrominated biphenyls, polybrominated diphenyl ethers, and phthalates).

Q: Are there any temperature range limitations I should consider?

A: Most substitute parts operate across -55°C to 150°C. The SMBJ33CA (MDD) has a reduced lower limit of -50°C, which may be unsuitable for extreme cold environments. The SMBJ33CA-TP (Micro Commercial Co) extends to 175°C upper limit, beneficial for high-temperature applications. The original 1SMB33CAT3 and Littelfuse options support -65°C lower limit for enhanced cold-temperature performance.

Q: Does the 11.8A peak pulse current of the SMBJ33CA-TR provide any advantage?

A: The SMBJ33CA-TR (STMicroelectronics) with 11.8A peak pulse current exceeds the 11.3A specification, providing approximately 4.4% additional transient current handling capacity. This offers enhanced protection margin but does not alter the fundamental voltage clamping characteristics (53.3V maximum).

Q: What packaging options are available?

A: All substitute parts are supplied in DO-214AA (SMB) surface mount package format, identical to the original 1SMB33CAT3. Packaging variants (Cut Tape, Tape & Reel, Digi-Reel) differ only in delivery format and do not affect electrical or mechanical performance.

Q: Is the MSL (Moisture Sensitivity Level) rating consistent across all parts?

A: Yes. All parts, including the original 1SMB33CAT3 and all substitutes, carry MSL 1 (Unlimited) rating, indicating no moisture sensitivity restrictions during storage or handling.

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