SMF17AT1 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SMF17AT1 is a unidirectional Zener-type transient voltage suppressor manufactured by onsemi, designed for general-purpose overvoltage protection in surface-mount applications. Specified with a 17V reverse standoff voltage and 27.6V maximum clamping voltage at 7.2A peak pulse current, this component operates across -55°C to 150°C in a SOD-123FL package.

The SMF17AT1 is classified as obsolete. Locating equivalent or substitute parts is necessary for new designs, production continuity, and long-term component availability. Substitute parts must maintain electrical compatibility within the SOD-123F/SMF package family while meeting the same 200W peak pulse power rating and general-purpose protection requirements.

Substiute Parts

SMF17AT1

onsemiIn Stock: 1132SMF17AT1 Datasheet

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SMF11A

MDDIn Stock: 17334SMF11A Datasheet

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SMF12A

MDDIn Stock: 26418SMF12A Datasheet

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SMF13A

Diotec SemiconductorIn Stock: 20101SMF13A Datasheet

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SMF15A

MDDIn Stock: 29220SMF15A Datasheet

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SMF16A

MDDIn Stock: 20966SMF16A Datasheet

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SMF18A

MDDIn Stock: 20944SMF18A Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SMF17AT1 are selected based on the following electrical and mechanical criteria:

Electrical Compatibility Parameters:

• Unidirectional Zener-type TVS diode topology
• Peak pulse power rating of 200W
• Operating temperature range of -55°C to 150°C or wider
• Surface-mount package compatibility (SOD-123F or SMF designation)
• General-purpose overvoltage protection application class

Voltage Rating Considerations: Substitute parts are grouped by reverse standoff voltage (Vwm) and maximum clamping voltage (Vc). The SMF17AT1 operates at 17V standoff with 27.6V clamping. Acceptable substitutes maintain the same package footprint and power rating while offering voltage ratings within the SMF series range (11V to 18V standoff). Selection depends on the specific circuit protection requirement; lower voltage ratings provide tighter clamping, while higher ratings offer reduced leakage current.

Current and Clamping Characteristics: Peak pulse current (Ipp) and clamping voltage vary inversely across the SMF series. Parts with lower standoff voltages exhibit higher peak pulse current capability; parts with higher standoff voltages exhibit lower peak pulse current but higher clamping voltages. Circuit design determines which trade-off is acceptable.

Compliance and Availability: Active-status substitutes from MDD and Diotec Semiconductor offer RoHS3 compliance and current production availability, addressing the obsolescence of the original onsemi part.

Parameter Comparison

Engineering Selection Recommendations

For Direct Voltage Replacement (17V Protection): SMF16A (16V standoff, 26V clamping) and SMF18A (18V standoff, 29.2V clamping) bracket the original 17V specification. SMF16A provides slightly tighter clamping (26V vs. 27.6V) with marginally higher peak pulse current (7.7A vs. 7.2A). SMF18A provides higher clamping voltage (29.2V) with lower peak pulse current (6.8A). Both are active-status parts with RoHS3 compliance and current production availability.

For Lower Voltage Protection Requirements: SMF11A through SMF15A offer progressively lower standoff voltages (11V to 15V) with correspondingly lower clamping voltages and higher peak pulse current ratings. These parts are suitable for circuits requiring protection at lower voltage thresholds.

Compliance Considerations: All substitute parts listed are RoHS3 compliant, addressing regulatory requirements that the obsolete SMF17AT1 does not meet. For applications requiring RoHS compliance, any substitute from the active-status list is acceptable from a regulatory standpoint.

Production Availability: MDD and Diotec Semiconductor maintain active production status for all substitute parts, with inventory quantities ranging from 17,300 to 29,200 pieces. The original onsemi SMF17AT1 is obsolete with limited remaining stock (1,066 pieces).

Frequently Asked Questions (FAQ)

Q: Can I use SMF16A or SMF18A as a direct replacement for SMF17AT1?

A: Both SMF16A and SMF18A are mechanically and electrically compatible substitutes. SMF16A (16V standoff, 26V clamping) provides clamping voltage slightly below the original specification. SMF18A (18V standoff, 29.2V clamping) provides clamping voltage above the original specification. Selection depends on whether your circuit requires clamping voltage at or below 27.6V. Both parts share the same SOD-123F package footprint and 200W power rating.

Q: What is the difference between SMF11A and SMF18A?

A: These parts represent opposite ends of the SMF series voltage range. SMF11A operates at 11V standoff with 18.2V clamping and 11A peak pulse current, suitable for lower-voltage protection circuits. SMF18A operates at 18V standoff with 29.2V clamping and 6.8A peak pulse current, suitable for higher-voltage protection circuits. Peak pulse current and clamping voltage trade off inversely across the series.

Q: Are all substitute parts RoHS compliant?

A: Yes. All substitute parts listed (SMF11A, SMF12A, SMF13A, SMF15A, SMF16A, SMF18A) are RoHS3 compliant. The original SMF17AT1 is RoHS non-compliant. If your application requires RoHS compliance, any substitute from this list meets that requirement.

Q: Do all substitute parts use the same package as SMF17AT1?

A: Yes. All substitute parts use SOD-123F or SMF package designations, which are mechanically identical and footprint-compatible. The supplier device package designation is SOD-123FL for all parts, confirming package compatibility for PCB assembly.

Q: What is the operating temperature range for these parts?

A: Most substitute parts operate across -55°C to 150°C (TJ), matching the original SMF17AT1 specification. SMF13A operates across -50°C to 150°C (TJ), a slightly narrower range at the lower temperature extreme. For applications requiring -55°C operation, SMF11A, SMF12A, SMF15A, SMF16A, or SMF18A are appropriate selections.

Q: How do I choose between substitute parts with different voltage ratings?

A: Selection is determined by your circuit's protection requirement. If your circuit protects a 17V rail, SMF16A or SMF18A are closest matches. If your circuit protects a lower-voltage rail (11V to 15V), select the corresponding SMF part. The standoff voltage (Vwm) should match or slightly exceed your protected rail voltage; the clamping voltage (Vc) determines the maximum transient voltage the protected circuit will experience.