1SMB45AT3 Equivalent & Substitute Parts

Part Overview

The 1SMB45AT3 is a unidirectional transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface-mount applications. This component features a 45V reverse standoff voltage, 72.7V maximum clamping voltage, and 8.3A peak pulse current capability in a DO-214AA (SMB) package. The part is currently classified as obsolete, making equivalent substitutes necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	45	V
Voltage - Breakdown (Min)	50	V
Voltage - Clamping (Max) @ Ipp	72.7	V
Current - Peak Pulse (10/1000µs)	8.3	A
Power - Peak Pulse	600	W
Package / Case	DO-214AA, SMB	-
Operating Temperature Range	-65 to 150	°C (TJ)
Mounting Type	Surface Mount	-

Substitute Part Grouping Explanation

Substitution eligibility for the 1SMB45AT3 is determined by the following critical parameters:

Voltage - Reverse Standoff (Typ): 45V
Voltage - Breakdown (Min): 50V
Voltage - Clamping (Max) @ Ipp: 72.7V
Current - Peak Pulse (10/1000µs): 8.3A
Power - Peak Pulse: 600W
Package / Case: DO-214AA, SMB
Unidirectional Channels: 1

Substitute parts are classified into two categories:

Direct Substitutes: Parts matching all critical electrical parameters (45V standoff, 50V breakdown, 72.7V clamping, 8.3A peak pulse, 600W peak power) and identical package specifications.

Similar Substitutes: Parts meeting the core voltage and current requirements but with minor variations in clamping voltage, peak power, or operating temperature range. These parts are functionally equivalent for general-purpose transient suppression but may require application-level verification for specific circuit constraints.

Parameter Comparison

Part Number	Manufacturer	Standoff (V)	Breakdown (V)	Clamping (V)	Peak Pulse (A)	Peak Power (W)	Package	Status	RoHS
1SMB45AT3	onsemi	45	50	72.7	8.3	600	DO-214AA, SMB	Obsolete	Non-compliant
SMBJ45A	MDD	45	50	72.7	8.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ45A-13-F	Diodes Incorporated	45	50	72.7	8.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ45A-HRA	Littelfuse	45	50	72.7	8.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ45A-HR	Littelfuse Inc.	45	50	72.7	8.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ45A-M3/52	Vishay General Semiconductor - Diodes Division	45	50	72.7	8.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ45A-M3/5B	Vishay General Semiconductor - Diodes Division	45	50	72.7	8.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ45AE3/TR13	Microchip Technology	45	50	72.7	8.3	600	DO-214AA, SMB	Active	ROHS3 Compliant
SACB45	Littelfuse Inc.	45	50	77	6.8	500	DO-214AA, SMB	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (Direct Electrical & Package Match):

SMBJ45A (MDD), SMBJ45A-13-F (Diodes Incorporated), SMBJ45A-HRA (Littelfuse), SMBJ45A-HR (Littelfuse Inc.), SMBJ45A-M3/52 (Vishay), SMBJ45A-M3/5B (Vishay), and SMBJ45AE3/TR13 (Microchip Technology) are direct functional equivalents. All maintain identical electrical specifications (45V standoff, 50V breakdown, 72.7V clamping, 8.3A peak pulse, 600W peak power) and DO-214AA/SMB packaging. All substitute parts carry active product status and ROHS3 compliance, addressing the obsolescence and RoHS non-compliance of the original 1SMB45AT3.

Secondary Substitute (Similar Electrical Performance):

SACB45 (Littelfuse Inc.) meets the core voltage requirements (45V standoff, 50V breakdown) and identical packaging but differs in clamping voltage (77V vs. 72.7V) and peak pulse current (6.8A vs. 8.3A). This part is suitable for applications where the slightly higher clamping voltage and reduced peak current capability do not conflict with circuit protection requirements.

All substitute parts are manufactured by established semiconductor suppliers with active product status, ensuring long-term availability and supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can SMBJ45A directly replace 1SMB45AT3 without circuit modification?

A: Yes. SMBJ45A matches all critical electrical parameters (45V standoff, 50V breakdown, 72.7V clamping, 8.3A peak pulse) and uses identical DO-214AA/SMB packaging. No circuit redesign is required.

Q: What is the difference between SMBJ45A variants from different manufacturers?

A: All SMBJ45A variants (MDD, Diodes Incorporated, Littelfuse, Vishay, Microchip) share identical electrical specifications and packaging. Differences are limited to manufacturer-specific part number suffixes (e.g., -13-F, -HRA, -M3/52) which denote packaging configurations or tape specifications but do not affect electrical performance.

Q: Is SACB45 a suitable replacement for 1SMB45AT3?

A: SACB45 is functionally similar but not identical. It maintains the 45V standoff and 50V breakdown voltages but has a higher clamping voltage (77V vs. 72.7V) and lower peak pulse current (6.8A vs. 8.3A). Use SACB45 only if your circuit can tolerate these parameter variations.

Q: Why is the original 1SMB45AT3 marked as obsolete?

A: The 1SMB45AT3 is obsolete due to market consolidation and manufacturer discontinuation. Active equivalents from multiple suppliers ensure continued availability and support for new designs and legacy system maintenance.

Q: Are all substitute parts RoHS compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance status, whereas the original 1SMB45AT3 is RoHS non-compliant. This compliance improvement supports modern procurement and environmental regulatory requirements.

Q: What is the operating temperature range difference between substitutes?

A: The original 1SMB45AT3 operates from -65°C to 150°C. Most substitutes operate from -50°C to 150°C or -55°C to 150°C. Verify the specific operating temperature range of your selected substitute against your application requirements.

Q: Can I use SMBJ45A-M3/52 in tape-and-reel packaging for automated assembly?

A: Yes. SMBJ45A-M3/52 is supplied in Tape & Reel (TR) packaging, suitable for automated pick-and-place assembly. Confirm tape specifications with your supplier if your assembly equipment has specific tape format requirements.

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