Choosing a TVS by Standoff and Breakdown Definitions

1. Identify Normal Bus and Transient Context

Begin with the line that the TVS is intended to protect. Ask the circuit owner for the normal bus description and the transient requirement, including the source of each. Keep the circuit reference with those records. A supply label in an equipment specification may describe normal operation, but it does not identify the transient event that the component review is supposed to address.

Separate the operating requirement from the disturbance description. The normal bus belongs to the operating record; the transient record should identify the event or accepted engineering reference used for evaluation. Where the design has several relevant situations, list them individually. This avoids comparing a supplier's protection headline with an application question that has never been defined in the same terms.

Clarify whether the enquiry seeks the released TVS or a proposed candidate. Retain the incumbent's full manufacturer code and documentation when available. If only a generic TVS description has survived in the BOM, ask the component owner to resolve its identity. The voltage comparison should begin after the requested item and the meaning of the requirement are sufficiently clear to review.

2. Keep Three Voltage Definitions Separate

Nexperia's explanation distinguishes reverse working or standoff voltage from reverse breakdown voltage. The working field concerns the normal-operation basis; breakdown identifies the transition into the described breakdown behaviour. Clamping is another parameter associated with the transient response. Preserve these names in a comparison, allowing the reviewer to see which quantity each manufacturer statement actually describes.

A field headed voltage is too broad for this decision. Use separate entries for working, breakdown and clamping, with the source conditions next to each. Request clarification when a catalogue or quotation supplies one number without identifying the parameter. An apparent match can disappear when the two documents are found to be describing different quantities, so resolve the labels before ranking the candidates.

Read the exact proposed device's definitions and conditions rather than importing a fixed relationship from a general explanation. Keep minimum, typical or maximum classifications where the applicable source gives them. The purpose is a consistent comparison of the named fields. It does not call for selecting a universal percentage between them or translating an abbreviated headline into a complete engineering choice.

3. Retain Pulse Conditions and Missing Limits

Pulse context belongs beside the clamping and transient information. Preserve the waveform or test reference actually stated in the candidate document and the event reference supplied by engineering. Those records describe different sides of the comparison. Do not assign a published test pulse to the customer's circuit solely because it appears in the component's general product description.

When the application event and source conditions differ, identify the difference for the protection reviewer. Useful questions concern which event is covered, which exact-device evidence applies and which limits remain unresolved. Keep a missing condition as an open field rather than completing it from a neighbouring product. This creates an actionable request for evidence without producing an unsupported pulse calculation.

Document changes to the transient requirement as carefully as changes to the part. A new input source, interface use or accepted engineering event may require reconsideration even while the TVS code stays unchanged. The comparison should say which design revision it covers. A clamping statement tied to one source condition remains a component statement until the circuit owner assesses its relevance to the updated requirement.

4. Release a Bounded TVS Requirement

Prepare a TVS-specific release record containing the complete code, normal-bus reference, separate voltage definitions and applicable transient conditions. Record the engineer's disposition against each candidate and each material difference. This makes it possible to distinguish an identity match from a proposal whose voltage evidence is still under review, without hiding the unresolved fields beneath a general protection category.

Keep the wider circuit-protection assessment visible. The owner decides what additional component and application checks are required and where their accepted results are recorded. Matching the names of voltage parameters does not establish the protected assembly's behaviour. A component document and a completed customer evaluation answer different questions; link the latter only when the responsible team has supplied it.

For an ICULTRA enquiry, provide the permitted TVS code, quantity and destination, with any candidate's unresolved voltage or pulse questions listed separately. Include shareable manufacturer references rather than a detached voltage shorthand. Once engineering accepts a changed requirement, update the purchase record with its decision reference. This gives subsequent quotations a consistent technical basis while commercial terms are confirmed for the exact item.

Sources and further reading

• Nexperia: What are TVS diodes and how do you choose the right one?

Manufacturer documents support the technical guidance above. They do not confirm our stock, authorisation or the condition of any offered lot.