SMF12AT3G Equivalent & Substitute Parts

Part Overview

The SMF12AT3G 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 12V reverse standoff voltage with a 19.9V maximum clamping voltage and 10.1A peak pulse current capability in a SOD-123FL package. The part is currently classified as obsolete, making equivalent substitutes necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Manufacturer Part Number	SMF12AT3G
Manufacturer	onsemi
Category	Transient Voltage Suppressors (TVS)
Type	Zener
Unidirectional Channels	1
Voltage - Reverse Standoff (Typ)	12V
Voltage - Breakdown (Min)	13.3V
Voltage - Clamping (Max) @ Ipp	19.9V
Current - Peak Pulse (10/1000µs)	10.1A
Power - Peak Pulse	200W
Mounting Type	Surface Mount
Package / Case	SOD-123F
Operating Temperature	-55°C ~ 150°C (TJ)
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the SMF12AT3G is determined by matching the following critical electrical parameters:

Voltage - Reverse Standoff (Typ): 12V
Voltage - Clamping (Max) @ Ipp: 19.9V
Current - Peak Pulse (10/1000µs): 10.1A
Power - Peak Pulse: 200W
Unidirectional Channels: 1
Mounting Type: Surface Mount
Package compatibility: SOD-123F or equivalent

Direct substitutes maintain identical electrical specifications and package form factors. Similar parts operate within the SMF series voltage range but with different standoff voltages and clamping characteristics, suitable for applications with relaxed voltage tolerance requirements.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Package / Case	Product Status
SMF12AT3G	onsemi	12V	19.9V	10.1A	200W	SOD-123F	Obsolete
SMF12A	MDD	12V	19.9V	10.1A	200W	SOD-123F	Active
SMF12A-E3-08	Vishay General Semiconductor - Diodes Division	12V	19.9V	10.1A	200W	DO-219AB	Active
SMF12A-TP	Micro Commercial Co	12V	19.9V	10.1A	200W	SOD-123F	Active
SMF11A	MDD	11V	18.2V	11A	200W	SOD-123F	Active
SMF13A	Diotec Semiconductor	13V	21.5V	9.3A	200W	SOD-123F	Active
SMF15A	MDD	15V	24.4V	8.2A	200W	SOD-123F	Active
SMF16A	MDD	16V	26V	7.7A	200W	SOD-123F	Active
SMF17A	Diotec Semiconductor	17V	27.6V	7.25A	200W	SOD-123F	Active
SMF18A	MDD	18V	29.2V	6.8A	200W	SOD-123F	Active

Engineering Selection Recommendations

Direct Substitutes (Identical Electrical Performance):

SMF12A, SMF12A-E3-08, and SMF12A-TP are direct electrical equivalents to the SMF12AT3G. All three maintain the 12V reverse standoff voltage, 19.9V clamping voltage, and 10.1A peak pulse current. SMF12A and SMF12A-TP are available in SOD-123F packaging, matching the original form factor. SMF12A-E3-08 uses DO-219AB (SMF) packaging, which is mechanically compatible but requires PCB layout verification. All three substitute parts are in active production status with RoHS3 compliance and REACH unaffected classification.

Similar Voltage Series (Conditional Substitution):

SMF11A, SMF13A, SMF15A, SMF16A, SMF17A, and SMF18A operate within the SMF series with different voltage ratings. These parts are suitable only for applications where the protected circuit can tolerate voltage deviations from the original 12V specification. SMF11A provides lower voltage protection (11V standoff), while SMF13A through SMF18A provide progressively higher voltage ratings. All similar parts maintain 200W peak pulse power and SOD-123F packaging compatibility. Selection among similar parts depends on the specific overvoltage threshold requirements of the target application.

Frequently Asked Questions (FAQ)

Q: Can SMF12A directly replace SMF12AT3G without circuit modification?

A: Yes. SMF12A is a direct electrical equivalent with identical voltage and current ratings. If using SMF12A in SOD-123F packaging, no circuit changes are required. If selecting SMF12A-E3-08 with DO-219AB packaging, verify PCB pad layout compatibility before assembly.

Q: What is the difference between direct substitutes and similar parts?

A: Direct substitutes (SMF12A, SMF12A-E3-08, SMF12A-TP) maintain the exact 12V reverse standoff and 19.9V clamping specifications. Similar parts (SMF11A through SMF18A) have different voltage ratings and are suitable only if the application circuit can accept voltage deviations. Selecting a similar part requires circuit-level analysis to confirm protection adequacy.

Q: Are all substitute parts RoHS compliant?

A: All listed substitute parts are RoHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: Does package type affect electrical performance?

A: No. SOD-123F and DO-219AB (SMF) packages are electrically equivalent for this TVS diode category. Package selection is determined by PCB layout and assembly process compatibility, not electrical function.

Q: Why is SMF12AT3G marked as obsolete?

A: Obsolescence indicates the part is no longer manufactured by onsemi. Active production alternatives from MDD, Vishay, Micro Commercial Co, and Diotec Semiconductor provide equivalent functionality with ongoing supply availability.

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