1SMB51CAT3 Equivalent & Substitute Parts

Part Overview

The 1SMB51CAT3 is a transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface mount applications. This bidirectional TVS diode features a 51V reverse standoff voltage with an 82.4V maximum clamping voltage and 7.3A peak pulse current capability in a DO-214AA (SMB) package. The part is currently obsolete, making equivalent and substitute parts necessary for ongoing design support and production requirements.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	51	V
Voltage - Breakdown (Min)	56.7	V
Voltage - Clamping (Max) @ Ipp	82.4	V
Current - Peak Pulse (10/1000µs)	7.3	A
Power - Peak Pulse	600	W
Bidirectional Channels	1	—
Package / Case	DO-214AA, SMB	—
Operating Temperature Range	-65°C ~ 150°C	TJ
Mounting Type	Surface Mount	—
Applications	General Purpose	—

Substitute Part Grouping Explanation

Substitution for the 1SMB51CAT3 is determined by strict equivalence of the following electrical and mechanical parameters:

Voltage - Reverse Standoff (Typ): 51V
Voltage - Clamping (Max) @ Ipp: 82.4V
Current - Peak Pulse (10/1000µs): 7.3A
Power - Peak Pulse: 600W
Package / Case: DO-214AA, SMB
Bidirectional operation: 1 channel

Substitute parts are grouped into two categories:

Direct Equivalents: Parts that match all critical electrical parameters (51V standoff, 82.4V clamping, 7.3A peak pulse) and package specifications. These parts are fully interchangeable with the original 1SMB51CAT3.

Similar Parts: Parts that share the same package and general voltage class but differ in one or more electrical parameters. These parts may be suitable for applications with relaxed specifications but require design verification.

Parameter Comparison

Part Number	Manufacturer	Standoff Voltage (V)	Clamping Voltage (V)	Peak Pulse Current (A)	Peak Pulse Power (W)	Package	Product Status	RoHS Status
1SMB51CAT3	onsemi	51	82.4	7.3	600	DO-214AA, SMB	Obsolete	RoHS non-compliant
SMBJ51CA	MDD	51	82.4	7.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ51A	Good-Ark Semiconductor	51	82.4	7.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ51A-TP	Micro Commercial Co	51	82.4	7.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ51CA-13-F	Diodes Incorporated	51	82.4	7.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ51CA-HR	Littelfuse Inc.	51	82.4	7.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ51CA-HRA	Littelfuse Inc.	51	82.4	7.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ48CA	MDD	48	77.4	7.8	600	DO-214AA, SMB	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Replacement Parts: SMBJ51CA (MDD), SMBJ51A (Good-Ark Semiconductor), SMBJ51A-TP (Micro Commercial Co), SMBJ51CA-13-F (Diodes Incorporated), SMBJ51CA-HR (Littelfuse Inc.), and SMBJ51CA-HRA (Littelfuse Inc.) are electrically and mechanically equivalent to the 1SMB51CAT3. All direct replacements are manufactured by active suppliers and comply with ROHS3 standards, providing improved regulatory compliance compared to the obsolete original part.

Alternative Part: SMBJ48CA (MDD) operates at a lower voltage class (48V standoff, 77.4V clamping) with slightly higher peak pulse current (7.8A). This part is suitable only for applications where the lower voltage rating is acceptable and does not compromise circuit protection requirements.

Selection should prioritize parts from active suppliers with current product status and ROHS3 compliance. Operating temperature range should be verified against application requirements, as some substitutes support extended temperature ranges (-55°C to -65°C minimum).

Frequently Asked Questions (FAQ)

Q: Can SMBJ51CA directly replace 1SMB51CAT3? A: Yes. SMBJ51CA matches all critical electrical parameters (51V standoff, 82.4V clamping, 7.3A peak pulse) and package specifications (DO-214AA, SMB). The primary difference is product status and RoHS compliance.

Q: What is the difference between SMBJ51CA-HR and SMBJ51CA-HRA? A: Both parts are manufactured by Littelfuse Inc. and share identical electrical specifications. The designation difference reflects internal product line categorization. Both are electrically equivalent and suitable for direct substitution.

Q: Is SMBJ48CA a suitable replacement? A: SMBJ48CA is electrically different, with lower standoff voltage (48V vs. 51V) and clamping voltage (77.4V vs. 82.4V). It is suitable only if the application circuit can tolerate these lower voltage ratings without compromising protection performance.

Q: Are all substitute parts available in the same package? A: Yes. All listed substitute parts use the DO-214AA (SMB) surface mount package, ensuring mechanical compatibility with existing PCB designs.

Q: What is the significance of RoHS compliance? A: The original 1SMB51CAT3 is RoHS non-compliant. All active substitute parts listed are ROHS3 compliant, meeting current environmental and regulatory requirements for new designs and production.

Q: Do operating temperature ranges differ between substitutes? A: Yes. The original part operates from -65°C to 150°C. Some substitutes (SMBJ51A-TP, SMBJ51CA-HR, SMBJ51CA-HRA) support -55°C to 150°C or -65°C to 150°C ranges. Verify temperature requirements for your specific application.

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