SMF48AT1G Transient Voltage Suppressor - Equivalent & Substitute Parts

Part Overview

The SMF48AT1G is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component features a 48V reverse standoff voltage with a 77.4V maximum clamping voltage and 2.6A peak pulse current capability in a SOD-123FL package.

The SMF48AT1G is classified as obsolete. Identifying functionally equivalent substitute parts is necessary to maintain design continuity and ensure component availability for new production runs and field replacements.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	48	V
Voltage - Breakdown (Min)	53.3	V
Voltage - Clamping (Max) @ Ipp	77.4	V
Current - Peak Pulse (10/1000µs)	2.6	A
Power - Peak Pulse	200	W
Package / Case	SOD-123F	—
Operating Temperature Range	-55 to 150	°C
Type	Zener	—
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the SMF48AT1G are grouped based on strict electrical and mechanical compatibility criteria. The primary substitution parameters are:

Voltage - Reverse Standoff (Typ): 48V
Voltage - Clamping (Max) @ Ipp: 77.4V
Current - Peak Pulse (10/1000µs): 2.6A (or within 0.1A tolerance)
Power - Peak Pulse: 200W
Package / Case: SOD-123F or equivalent surface-mount package
Type: Unidirectional Zener diode
RoHS3 Compliance

Parts meeting these criteria are classified as direct substitutes. The SMF54A, while maintaining the same power rating and package, operates at a higher voltage class (54V standoff, 87.1V clamping) and is listed as a manufacturer-recommended alternative for applications requiring higher voltage protection margins.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Clamping (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Package	Product Status	Operating Temp (°C)
SMF48AT1G	Littelfuse Inc.	48	77.4	2.6	200	SOD-123F	Obsolete	-55 to 150
SMF48A	Meritek	48	77.4	2.58	200	SOD-123FL	Active	-55 to 150
SMF48A-T13	Littelfuse Inc.	48	77.4	2.6	200	SOD-123F	Active	-55 to 150
SMF48A-E3-08	Vishay General Semiconductor - Diodes Division	48	77.4	2.6	200	DO-219AB	Active	-65 to 175
SMF48A-TP	Micro Commercial Co	48	77.4	2.6	200	SOD-123F	Active	-65 to 175
SMF54A	Diotec Semiconductor	54	87.1	2.3	200	SOD-123F	Active	-50 to 150

Engineering Selection Recommendations

For direct replacement of the obsolete SMF48AT1G, select from the following active-status parts that maintain identical electrical specifications:

Primary Substitutes (Identical Voltage and Current Ratings):

SMF48A-T13 (Littelfuse Inc.) - Maintains original manufacturer continuity with active product status and identical electrical parameters
SMF48A-TP (Micro Commercial Co) - Extends operating temperature range to -65°C to 175°C
SMF48A (Meritek) - Minimal current variance (2.58A vs 2.6A) with active inventory status

Package Consideration:

SMF48A-E3-08 (Vishay) uses DO-219AB package instead of SOD-123F; verify PCB footprint compatibility before selection

Higher Voltage Alternative:

SMF54A (Diotec Semiconductor) - Manufacturer-recommended substitute with elevated voltage ratings (54V standoff, 87.1V clamping); suitable only for applications where higher voltage protection margins are acceptable

All substitute parts maintain ROHS3 compliance and are available in active production status.

Frequently Asked Questions (FAQ)

Q: Can SMF48A-E3-08 be used as a direct replacement for SMF48AT1G?

A: SMF48A-E3-08 is electrically equivalent but uses a DO-219AB package instead of SOD-123F. Physical footprint compatibility must be verified against your PCB layout before substitution.

Q: What is the difference between SMF48A and SMF48A-T13?

A: Both parts are electrically identical with 48V standoff and 77.4V clamping voltages. SMF48A-T13 is supplied in Tape & Reel packaging, while SMF48A specifications do not specify packaging format. Both are manufactured by Littelfuse Inc. or authorized suppliers and are suitable for direct substitution.

Q: Is SMF54A a suitable replacement for SMF48AT1G?

A: SMF54A is a manufacturer-recommended alternative with higher voltage ratings (54V standoff vs 48V, 87.1V clamping vs 77.4V). It is suitable only for applications where the higher voltage protection threshold does not conflict with circuit design requirements. Peak pulse current is lower (2.3A vs 2.6A).

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance status, consistent with the original SMF48AT1G specification.

Q: What is the inventory status of these substitutes?

A: SMF48A-T13, SMF48A, SMF54A, and SMF48A-TP are all in active production with confirmed new original stock availability. SMF48A-E3-08 is also actively stocked.

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