1SMB48AT3 Equivalent & Substitute Parts

Part Overview

The 1SMB48AT3 is a transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface-mount applications. This unidirectional Zener diode features a 48V reverse standoff voltage with a 77.4V maximum clamping voltage and 7.7A peak pulse current capability in the DO-214AA (SMB) package. The part is currently obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value
Manufacturer Part Number	1SMB48AT3
Manufacturer	onsemi
Category	Transient Voltage Suppressors (TVS)
Type	Zener
Unidirectional Channels	1
Voltage - Reverse Standoff (Typ)	48V
Voltage - Breakdown (Min)	53.3V
Voltage - Clamping (Max) @ Ipp	77.4V
Current - Peak Pulse (10/1000µs)	7.7A
Power - Peak Pulse	600W
Package / Case	DO-214AA, SMB
Mounting Type	Surface Mount
Operating Temperature	-65°C ~ 150°C (TJ)
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution of the 1SMB48AT3 is determined by strict electrical and mechanical parameter matching:

Critical Matching Parameters:

Voltage - Reverse Standoff: 48V (exact match required)
Voltage - Clamping (Max) @ Ipp: 77.4V (exact match required)
Current - Peak Pulse (10/1000µs): 7.7A minimum (tolerance range 7.7A to 8.1A acceptable)
Power - Peak Pulse: 600W (exact match required)
Package / Case: DO-214AA, SMB (exact match required)
Mounting Type: Surface Mount (exact match required)
Unidirectional Channels: 1 (exact match required)
Type: Zener (exact match required)

All identified substitute parts meet these electrical and mechanical requirements. Substitute parts from Meritek, STMicroelectronics, Diodes Incorporated, Littelfuse Inc., Micro Commercial Co, and Vishay General Semiconductor maintain full compatibility with the original 1SMB48AT3 specification.

Parameter Comparison

Parameter	1SMB48AT3 (onsemi)	SMBJ48A (Meritek)	SMBJ48A-TR (STMicroelectronics)	SMBJ48A-13-F (Diodes Inc.)	SMBJ48A-HR (Littelfuse)	SMBJ48A-HRA (Littelfuse)	SMBJ48A-M3/52 (Vishay)	SMBJ48A-M3/5B (Vishay)	SMBJ48A-TP (MCC)
Voltage - Reverse Standoff (Typ)	48V	48V	48V	48V	48V	48V	48V	48V	48V
Voltage - Breakdown (Min)	53.3V	53.3V	53.3V	53.3V	53.3V	53.3V	53.3V	53.3V	53.3V
Voltage - Clamping (Max) @ Ipp	77.4V	77.4V	77.4V	77.4V	77.4V	77.4V	77.4V	77.4V	77.4V
Current - Peak Pulse (10/1000µs)	7.7A	7.75A	8.1A	7.7A	7.8A	7.8A	7.8A	7.8A	7.7A
Power - Peak Pulse	600W	600W	600W	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	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Operating Temperature	-65°C ~ 150°C (TJ)	-55°C ~ 150°C	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-65°C ~ 150°C (TJ)	-65°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 175°C (TJ)
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

All substitute parts listed are active production components from established manufacturers, providing superior availability compared to the obsolete 1SMB48AT3. All substitutes achieve ROHS3 compliance, addressing regulatory requirements that the original part does not meet.

For applications requiring the original -65°C lower operating temperature limit, SMBJ48A-HR, SMBJ48A-HRA from Littelfuse Inc. maintain this specification. For applications with extended upper temperature requirements, SMBJ48A-TP from Micro Commercial Co extends operation to 175°C.

Peak pulse current tolerance variations (7.7A to 8.1A) across substitute options remain within acceptable design margins for general-purpose transient voltage suppression. All parts maintain identical voltage clamping and reverse standoff specifications.

Frequently Asked Questions (FAQ)

Q: Can I directly replace 1SMB48AT3 with any of these substitute parts?

A: Yes. All listed substitute parts match the critical electrical parameters (48V reverse standoff, 77.4V clamping voltage, 600W peak pulse power) and package specification (DO-214AA SMB). Direct PCB footprint compatibility is maintained.

Q: What is the difference between the various Littelfuse and Vishay part numbers?

A: SMBJ48A-HR and SMBJ48A-HRA from Littelfuse, and SMBJ48A-M3/52 and SMBJ48A-M3/5B from Vishay represent different manufacturing codes and tape/reel configurations. Electrical specifications remain identical. Selection depends on packaging and supplier availability requirements.

Q: Does the peak pulse current variation (7.7A to 8.1A) affect circuit compatibility?

A: No. All substitute parts operate within the same voltage clamping envelope at their respective peak pulse currents. The 77.4V maximum clamping voltage is maintained across all options, ensuring equivalent transient suppression performance.

Q: Are all substitutes RoHS compliant?

A: Yes. All active substitute parts are ROHS3 compliant, unlike the original 1SMB48AT3. This addresses regulatory requirements for new designs and production.

Q: Which substitute should I select for low-temperature applications?

A: SMBJ48A-HR and SMBJ48A-HRA from Littelfuse maintain the -65°C lower operating temperature limit of the original part. Other substitutes operate to -55°C minimum.

Q: What packaging options are available?

A: Substitutes are available in Tape & Reel (TR) and Cut Tape (CT) configurations. SMBJ48A from Meritek and SMBJ48A-TR from STMicroelectronics offer standard reel packaging. Verify specific packaging availability with your supplier.

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