SMF51AT1 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SMF51AT1 is a unidirectional Zener-type transient voltage suppressor diode manufactured by onsemi, designed for general-purpose overvoltage protection applications. It features a 51V reverse standoff voltage with an 82.4V maximum clamping voltage and 2.4A peak pulse current capability in a surface-mount SOD-123F package. The part is currently classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing design support and procurement.

Substiute Parts

SMF51AT1

onsemiIn Stock: 1119SMF51AT1 Datasheet

Current PartRFQ

SMF51A-TP

Micro Commercial CoIn Stock: 11674SMF51A-TP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMF51AT1 is determined by strict equivalence across the following electrical and mechanical parameters:

• Voltage - Reverse Standoff (Typ): 51V
• Voltage - Breakdown (Min): 56.7V
• Voltage - Clamping (Max) @ Ipp: 82.4V
• Current - Peak Pulse (10/1000µs): 2.4A
• Power - Peak Pulse: 200W
• Package / Case: SOD-123F
• Mounting Type: Surface Mount
• Type: Zener
• Unidirectional Channels: 1

The SMF51A-TP manufactured by Micro Commercial Co meets all electrical specifications and mechanical requirements, making it a direct functional equivalent. Both parts share identical voltage ratings, current handling, power dissipation, and package configuration.

Parameter Comparison

Engineering Selection Recommendations

The SMF51A-TP is the direct functional equivalent for the obsolete SMF51AT1. Selection of the SMF51A-TP is supported by the following factors:

• All critical electrical parameters match exactly: voltage ratings, current capacity, and power dissipation.
• The SMF51A-TP maintains active product status, ensuring long-term availability and supply chain continuity.
• The SMF51A-TP achieves ROHS3 compliance, whereas the SMF51AT1 is non-compliant, providing regulatory advantage for new designs and procurement.
• Operating temperature range of the SMF51A-TP (-65 to 175°C) exceeds that of the SMF51AT1 (-55 to 150°C), offering extended thermal performance margin.
• Both parts are supplied in SOD-123F surface-mount packages with identical pinout and footprint compatibility.
• The SMF51A-TP is available in Tape & Reel packaging, suitable for automated assembly processes.

Frequently Asked Questions (FAQ)

Q: Can the SMF51A-TP be used as a direct replacement for the SMF51AT1?

A: Yes. The SMF51A-TP is electrically and mechanically equivalent. All voltage ratings, current specifications, power dissipation, and package dimensions are identical. No circuit modifications are required.

Q: What are the key differences between these parts?

A: The SMF51AT1 is obsolete; the SMF51A-TP is active. The SMF51A-TP is ROHS3 compliant and offers an extended operating temperature range (-65 to 175°C versus -55 to 150°C). Packaging differs: SMF51AT1 is supplied in bulk; SMF51A-TP is supplied in Tape & Reel format.

Q: Are there any compatibility concerns with PCB footprints?

A: No. Both parts use the SOD-123F package with identical pinout and footprint. No PCB layout changes are necessary.

Q: Does the extended temperature range of the SMF51A-TP affect circuit performance?

A: The extended range provides additional thermal margin but does not alter electrical performance within the original operating window. The part remains suitable for the same applications.

Q: Is the Tape & Reel packaging of the SMF51A-TP compatible with existing assembly processes?

A: Yes. Tape & Reel is the standard format for automated surface-mount assembly. If manual assembly or bulk handling is required, the SMF51A-TP can be obtained in alternative packaging through the supplier.

Q: What is the impact of ROHS3 compliance on part selection?

A: ROHS3 compliance ensures the SMF51A-TP meets current environmental and regulatory standards. For new designs and regulated applications, ROHS3 compliance is required. The obsolete SMF51AT1 does not meet this requirement.