1SMB40CAT3 Equivalent & Substitute Parts

Part Overview

The 1SMB40CAT3 is a transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface-mount applications. This component features a 40V reverse standoff voltage with 64.5V clamping capability and 9.3A peak pulse current handling in the DO-214AA (SMB) package format.

The 1SMB40CAT3 is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this TVS diode specification.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	40	V
Voltage - Breakdown (Min)	44.4	V
Voltage - Clamping (Max) @ Ipp	64.5	V
Current - Peak Pulse (10/1000µs)	9.3	A
Power - Peak Pulse	600	W
Package / Case	DO-214AA, SMB	—
Operating Temperature Range	-65°C to 150°C	TJ
Bidirectional Channels	1	—
Capacitance @ 1MHz	220	pF

Substitute Part Grouping Explanation

Substitute parts for the 1SMB40CAT3 are qualified based on the following critical parameters:

Voltage - Reverse Standoff (Typ): 40V
Voltage - Clamping (Max) @ Ipp: 64.5V
Current - Peak Pulse (10/1000µs): 9.3A (±0.4A tolerance acceptable)
Power - Peak Pulse: 600W
Package / Case: DO-214AA, SMB
Bidirectional Channels: 1
Mounting Type: Surface Mount

Parts meeting these electrical and mechanical specifications are considered direct substitutes. Parts with identical reverse standoff and clamping voltages but differing peak pulse current specifications are classified as similar substitutes, provided the current rating meets or exceeds the original specification.

Parameter Comparison

Part Number	Manufacturer	VWM (V)	VC (V)	Ipp (A)	Pkg	Status	RoHS
1SMB40CAT3	onsemi	40	64.5	9.3	DO-214AA	Obsolete	Non-compliant
SMBJ40CA	MDD	40	64.5	9.3	DO-214AA	Active	ROHS3
SMBJ40CA-TR	STMicroelectronics	40	64.5	9.7	DO-214AA	Active	ROHS3
SM6T47CAY	STMicroelectronics	40	84	48 (8/20µs)	DO-214AA	Active	ROHS3
SMBJ40CA-13-F	Diodes Incorporated	40	64.5	9.3	DO-214AA	Active	ROHS3
SMBJ40CA-HR	Littelfuse Inc.	40	64.5	9.3	DO-214AA	Active	ROHS3
SMBJ40CA-HRA	Littelfuse Inc.	40	64.5	9.3	DO-214AA	Active	ROHS3
SMBJ40CA-TP	Micro Commercial Co	40	64.5	9.3	DO-214AA	Active	ROHS3
SMBJ40CAE3/TR13	Microchip Technology	40	64.5	9.3	DO-214AA	Active	ROHS3

Engineering Selection Recommendations

Direct Substitutes (Electrical and Mechanical Equivalence):

SMBJ40CA (MDD), SMBJ40CA-13-F (Diodes Incorporated), SMBJ40CA-HR (Littelfuse Inc.), SMBJ40CA-HRA (Littelfuse Inc.), SMBJ40CA-TP (Micro Commercial Co), and SMBJ40CAE3/TR13 (Microchip Technology) are direct electrical and mechanical equivalents to the 1SMB40CAT3. All maintain identical reverse standoff voltage (40V), clamping voltage (64.5V), and peak pulse current (9.3A) specifications. All substitute parts are RoHS3 compliant and carry active product status, addressing the obsolescence of the original component.

Near-Equivalent Substitute (Slightly Enhanced Performance):

SMBJ40CA-TR (STMicroelectronics) provides electrical equivalence with a marginally higher peak pulse current rating of 9.7A, exceeding the original 9.3A specification. This part is suitable for applications where additional current margin is beneficial. Operating temperature range extends to -55°C minimum, matching the original -65°C specification of the 1SMB40CAT3.

Similar Substitute (Different Clamping Voltage):

SM6T47CAY (STMicroelectronics) shares the 40V reverse standoff voltage but features a higher clamping voltage of 84V and significantly elevated peak pulse current of 48A (8/20µs pulse). This part is classified as similar rather than direct substitute due to the different clamping characteristic. Selection of this part requires circuit-level analysis to confirm compatibility with the higher clamping voltage. This part carries AEC-Q101 automotive qualification.

Frequently Asked Questions (FAQ)

Q: Can SMBJ40CA-TR be used as a direct replacement for 1SMB40CAT3?

A: Yes. SMBJ40CA-TR maintains identical reverse standoff (40V) and clamping (64.5V) voltages. The peak pulse current of 9.7A exceeds the original 9.3A specification, providing additional margin. All electrical and mechanical parameters are compatible.

Q: What is the difference between SMBJ40CA variants from different manufacturers?

A: SMBJ40CA is offered by multiple manufacturers (MDD, Littelfuse, Micro Commercial Co, Microchip Technology) with identical electrical specifications. Variants such as -HR, -HRA, -TP, and -TR indicate different packaging formats (Tape & Reel, Cut Tape, Digi-Reel) and may reflect manufacturer-specific product lines. Electrical performance remains equivalent across all variants.

Q: Why is SM6T47CAY listed as a similar rather than direct substitute?

A: SM6T47CAY features a clamping voltage of 84V compared to the 1SMB40CAT3 specification of 64.5V. While both parts share the same 40V reverse standoff voltage and DO-214AA package, the higher clamping voltage may affect circuit behavior. Circuit-level verification is required before substitution.

Q: Are all substitute parts RoHS compliant?

A: All listed substitute parts carry RoHS3 compliance status. The original 1SMB40CAT3 is RoHS non-compliant. Substitution with any listed part addresses RoHS compliance requirements for new designs or production transitions.

Q: What packaging options are available for SMBJ40CA?

A: SMBJ40CA is available in multiple packaging formats: Tape & Reel (TR), Cut Tape (CT), Digi-Reel, and standard reel configurations. Selection depends on assembly equipment compatibility and procurement requirements. All variants maintain identical electrical specifications.

Q: Can the 1SMB40CAT3 be replaced in existing designs without circuit modification?

A: Direct substitutes (SMBJ40CA, SMBJ40CA-13-F, SMBJ40CA-HR, SMBJ40CA-HRA, SMBJ40CA-TP, SMBJ40CAE3/TR13, and SMBJ40CA-TR) require no circuit modification. All maintain identical electrical and mechanical specifications. Physical footprint compatibility with DO-214AA (SMB) package must be confirmed for PCB layout.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message