1SMB45CAT3 Equivalent & Substitute Parts

Part Overview

The 1SMB45CAT3 is a 45V Transient Voltage Suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface-mount applications. This component features a 72.2V maximum clamping voltage, 8.3A peak pulse current capability, and 600W peak pulse power rating in a DO-214AA (SMB) package.

The 1SMB45CAT3 is classified as obsolete. Equivalent and substitute parts listed below provide active alternatives with compatible electrical and mechanical specifications for continued circuit protection functionality.

Key Parameters

Parameter	Value
Manufacturer Part Number	1SMB45CAT3
Manufacturer	onsemi
Category	Transient Voltage Suppressors (TVS)
Package / Case	DO-214AA, SMB
Voltage - Reverse Standoff (Typ)	45V
Voltage - Breakdown (Min)	50V
Voltage - Clamping (Max) @ Ipp	72.2V
Current - Peak Pulse (10/1000µs)	8.3A
Power - Peak Pulse	600W
Operating Temperature Range	-65°C ~ 150°C (TJ)
Mounting Type	Surface Mount
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitute parts for the 1SMB45CAT3 are qualified based on the following electrical and mechanical parameters:

Critical Matching Parameters:

Voltage - Reverse Standoff (Typ): 45V
Voltage - Breakdown (Min): 50V
Current - Peak Pulse (10/1000µs): 8.3A (or equivalent)
Power - Peak Pulse: 600W
Package / Case: DO-214AA, SMB
Mounting Type: Surface Mount
Applications: General Purpose

Acceptable Variation Range:

Voltage - Clamping (Max) @ Ipp: 72.2V to 80.3V (within TVS diode tolerance specifications)
Operating Temperature: Minimum -55°C to -65°C; Maximum 150°C to 175°C

All substitute parts maintain identical reverse standoff voltage, breakdown voltage, peak pulse current, and package configuration. Clamping voltage variations remain within acceptable TVS diode performance tolerances for equivalent circuit protection.

Parameter Comparison

Parameter	1SMB45CAT3 (onsemi)	SMBJ45CA (MDD)	SMBJ45CA-13-F (Diodes Inc.)	SMBJ45CA-TP (MCC)	SMBJ45CAE3/TR13 (Microchip)	SMBJ45CE3/TR13 (Microchip)
Voltage - Reverse Standoff (Typ)	45V	45V	45V	45V	45V	45V
Voltage - Breakdown (Min)	50V	50V	50V	50V	50V	50V
Voltage - Clamping (Max) @ Ipp	72.2V	72.7V	72.7V	72.7V	72.7V	80.3V
Current - Peak Pulse (10/1000µs)	8.3A	8.3A	8.3A	8.3A	8.3A	7.5A
Power - Peak Pulse	600W	600W	600W	600W	600W	600W
Package / Case	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB
Operating Temperature Range	-65°C ~ 150°C	-50°C ~ 150°C	-55°C ~ 150°C	-55°C ~ 175°C	-65°C ~ 150°C	-65°C ~ 150°C
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility):

SMBJ45CA (MDD), SMBJ45CA-13-F (Diodes Incorporated), and SMBJ45CAE3/TR13 (Microchip) provide direct electrical equivalence to the 1SMB45CAT3. All three maintain 45V reverse standoff voltage, 50V minimum breakdown voltage, 8.3A peak pulse current, and 600W peak pulse power. All substitute parts are active products with ROHS3 compliance, addressing the obsolescence and RoHS non-compliance status of the original component.

Secondary Substitute (Acceptable with Design Review):

SMBJ45CA-TP (Micro Commercial Co) offers extended operating temperature range to 175°C and active product status. Peak pulse current remains at 8.3A with 600W power rating. This option is suitable for applications requiring elevated temperature performance.

Conditional Substitute (Application-Dependent):

SMBJ45CE3/TR13 (Microchip) features identical reverse standoff and breakdown voltages but exhibits 80.3V maximum clamping voltage and 7.5A peak pulse current. This part is suitable only for applications where the higher clamping voltage and reduced peak pulse current do not compromise circuit protection requirements. Design verification is necessary before selection.

Frequently Asked Questions (FAQ)

Q: Can SMBJ45CA-13-F directly replace 1SMB45CAT3 without circuit modification?

A: Yes. SMBJ45CA-13-F maintains identical reverse standoff voltage (45V), breakdown voltage (50V), peak pulse current (8.3A), and power rating (600W) in the same DO-214AA (SMB) package. Pin configuration and footprint are compatible. The part is active and ROHS3 compliant.

Q: What is the difference between SMBJ45CA and SMBJ45CAE3/TR13?

A: Both parts share identical electrical specifications: 45V standoff, 50V breakdown, 72.7V clamping, and 8.3A peak pulse current. The primary difference is packaging designation and manufacturer (MDD versus Microchip). Both are suitable substitutes for the 1SMB45CAT3.

Q: Why does SMBJ45CE3/TR13 have different clamping voltage and peak pulse current?

A: SMBJ45CE3/TR13 is a variant within the 45V standoff voltage family but with different internal design parameters. The 80.3V clamping voltage and 7.5A peak pulse current represent a different performance profile. This part is listed as a similar substitute but requires application-specific validation before use.

Q: Are all substitute parts available in the same SMB package?

A: Yes. All substitute parts are manufactured in DO-214AA (SMB) surface-mount package configuration, ensuring mechanical and footprint compatibility with the original 1SMB45CAT3 design.

Q: What is the inventory status of substitute parts?

A: SMBJ45CA (MDD) has 17,200 units in stock. SMBJ45CA-13-F (Diodes Incorporated) has 66,041 units available. SMBJ45CAE3/TR13 (Microchip) has 637 units. SMBJ45CA-TP (Micro Commercial Co) has 1,104 units. All parts are classified as new original stock.

Q: Does the RoHS compliance difference affect circuit performance?

A: RoHS compliance status does not affect electrical performance or circuit functionality. However, ROHS3-compliant substitutes (all listed alternatives) meet current environmental and regulatory requirements for new designs and manufacturing processes.

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