SMF30AT1 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SMF30AT1 is a unidirectional transient voltage suppressor diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface-mount applications. Specified with a 30V reverse standoff voltage and 48.4V maximum clamping voltage at 4.1A peak pulse current, this component operates across -55°C to 150°C. The part is classified as obsolete, necessitating identification of functionally equivalent alternatives from active product lines to maintain design continuity and ensure supply chain availability.

Substiute Parts

SMF30AT1

onsemiIn Stock: 947SMF30AT1 Datasheet

Current PartRFQ

SMF30A-E3-08

Vishay General Semiconductor - Diodes DivisionIn Stock: 5350SMF30A-E3-08 Datasheet

DirectRFQ

SMF20A

MDDIn Stock: 91902SMF20A Datasheet

SimilarRFQ

SMF22A

MDDIn Stock: 20428SMF22A Datasheet

SimilarRFQ

SMF24A

MDDIn Stock: 27644SMF24A Datasheet

SimilarRFQ

SMF26A

EVVO SemiIn Stock: 131159SMF26A Datasheet

SimilarRFQ

SMF28A

MDDIn Stock: 20400SMF28A Datasheet

SimilarRFQ

SMF33A

Diotec SemiconductorIn Stock: 18867SMF33A Datasheet

SimilarRFQ

SMF36A

MDDIn Stock: 20906SMF36A Datasheet

SimilarRFQ

SMF43A

Diotec SemiconductorIn Stock: 17205SMF43A Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMF30AT1 is determined by electrical parameter equivalence within defined tolerance bands and mechanical compatibility. The critical parameters governing substitutability are:

• Voltage - Reverse Standoff (Typ): Must match 30V to ensure correct circuit protection threshold
• Voltage - Clamping (Max) @ Ipp: Must match 48.4V to maintain transient suppression performance
• Current - Peak Pulse (10/1000µs): Must match 4.1A to ensure adequate surge handling capacity
• Power - Peak Pulse: Must match 200W dissipation rating
• Package / Case: SOD-123F or equivalent mechanical form factor for PCB compatibility
• Mounting Type: Surface mount configuration required

Substitute parts are classified into two categories:

Direct Equivalent: Parts with identical electrical specifications (30V standoff, 48.4V clamp, 4.1A peak pulse, 200W power rating) and compatible packaging.

Similar Alternatives: Parts within the SMF series with different voltage ratings but same power dissipation and mounting technology, suitable for applications where the exact voltage specification is not critical or where circuit design permits voltage adjustment.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: SMF30A-E3-08 (Vishay General Semiconductor)

The SMF30A-E3-08 is the direct electrical equivalent of the SMF30AT1, matching all critical parameters: 30V standoff voltage, 48.4V clamping voltage, and 4.1A peak pulse current. This part is manufactured by Vishay General Semiconductor under the active eSMP® series and carries ROHS3 compliance certification. The DO-219AB (SMF) package is mechanically compatible with SOD-123F footprints. This part is the preferred replacement for direct substitution without circuit modification.

Secondary Alternatives for Voltage-Flexible Applications

When circuit design permits voltage adjustment or when the exact 30V specification is not critical:

• SMF28A (MDD): 28V standoff, 45.4V clamp. Suitable for applications requiring slightly lower protection threshold with marginally higher peak pulse current capability (4.4A).
• SMF26A (EVVO Semi): 26V standoff, 42.1V clamp. Appropriate for lower-voltage protection circuits with higher current capacity (4.8A).
• SMF33A (Diotec Semiconductor): 33V standoff, 53.3V clamp. Suitable for applications requiring higher protection threshold with reduced peak pulse current (3.75A).

All recommended alternatives are active products with ROHS3 compliance and 200W power dissipation rating. Selection among secondary alternatives depends on specific circuit voltage requirements and transient current profiles.

Frequently Asked Questions (FAQ)

Q: Can SMF30A-E3-08 be used as a direct drop-in replacement for SMF30AT1?

A: Yes. The SMF30A-E3-08 matches all electrical specifications of the SMF30AT1 (30V standoff, 48.4V clamp, 4.1A peak pulse, 200W power). The DO-219AB package is mechanically compatible with SOD-123F PCB layouts. No circuit modification is required.

Q: What is the difference between SOD-123F and DO-219AB packaging?

A: SOD-123F and DO-219AB (SMF) are equivalent surface-mount packages for small-signal diodes. Both are compatible with standard PCB footprints for this component class. Mechanical dimensions and lead configurations are functionally identical for circuit board assembly.

Q: Can I use SMF28A or SMF26A instead of SMF30AT1?

A: SMF28A and SMF26A have lower standoff voltages (28V and 26V respectively) compared to the SMF30AT1 (30V). These parts are suitable only if your circuit design permits operation at reduced protection thresholds. Using a lower-voltage TVS diode may result in premature clamping and increased power dissipation during normal circuit operation.

Q: Are all substitute parts RoHS compliant?

A: The SMF30AT1 is RoHS non-compliant. All recommended substitute parts (SMF30A-E3-08, SMF28A, SMF26A, SMF33A, SMF36A, SMF43A) are ROHS3 compliant. If RoHS compliance is required for your application, any of these alternatives satisfy regulatory requirements.

Q: What determines whether I can use a different voltage rating TVS diode?

A: The standoff voltage must be selected based on your circuit's normal operating voltage. The TVS diode should not conduct during normal operation. Select a standoff voltage equal to or slightly above your circuit's maximum normal voltage. Peak pulse current and clamping voltage must be adequate to suppress transient overvoltages without exceeding component power dissipation limits.

Q: Is the SMF30AT1 still available for purchase?

A: The SMF30AT1 is classified as obsolete. Current inventory exists (893 pcs reported), but future availability is not guaranteed. SMF30A-E3-08 is the recommended active-product replacement with confirmed ongoing manufacturing and supply.