How to Review Repetitive-Surge Data from a TVS Diode Manufacturer

Author: ASIM Technical Team | Published: 2026-09-12

A TVS diode's peak pulse power is normally a single-pulse rating under stated waveform and thermal conditions. It is not, by itself, a repetitive-surge rating. When a circuit experiences frequent pulses, supplier approval has to answer a different question: how do clamp voltage, leakage, breakdown behavior, and package temperature change after a defined sequence of repeated events?

The most useful manufacturer report is not the one with the largest headline power. It is the one that makes the test reproducible.

Start by reconstructing the pulse conditions

Do not review “1,000 pulses passed” as a complete claim. Request the conditions that produced those pulses:

• waveform and source-network definition;

• peak current or source voltage and its tolerance;

• pulse width or rise and decay times;

• repetition interval, duty cycle, and total count;

• positive, negative, or alternating polarity;

• ambient temperature and starting junction condition;

• sample size, lot count, PCB or fixture, and mounting method;

• the failure criteria applied during and after the test.

These fields determine whether the report resembles the intended circuit. One thousand pulses separated by enough time for the package to return near ambient are not equivalent to a burst that accumulates heat. A waveform with the same peak current but a longer tail can deliver more energy. A result at room temperature cannot automatically establish behavior at the product's hot operating limit.

Separate three stress regimes

Repetition can mean different things, and each regime needs a different analysis.

A peak pulse power rating may help in the first regime. It says little about the third unless the datasheet or a separate qualification report supplies the duty and thermal model. For recurring surges, compute pulse energy from the actual voltage and current waveforms when possible, then estimate average heating from energy multiplied by repetition rate. Treat that estimate as a screening calculation, not as a replacement for measurement.

Ask for before-and-after electrical data

A pass/fail column can hide early degradation. Record electrical parameters before stress, after intermediate checkpoints, and after the final pulse count. The minimum useful set depends on the application, but commonly includes:

1. leakage at the specified reverse working voltage;

2. breakdown voltage at the stated test current;

3. clamp voltage at a controlled pulse current and waveform;

4. dynamic resistance or a comparable multi-current clamp assessment;

5. visual, package, and solder-joint inspection where relevant.

Leakage is important because a part may continue to avalanche while its off-state behavior has degraded. That can be unacceptable on a high-impedance node or in a low-power product even when no short circuit has formed. Clamp voltage should also be rechecked: a device that survives but allows higher residual voltage may no longer protect the downstream IC.

Use a table that preserves raw results rather than only a conclusion:

Do not fill missing fields with a catalog typical value. The purpose of the report is to show what the tested samples did.

Compare suppliers only under matched conditions

Supplier A may publish 600 W under one pulse definition, while Supplier B publishes 1,000 W under another. Ranking them by the wattage alone is not a valid comparison. Normalize the test where possible:

• use the same waveform and peak current;

• keep the same interval and pulse count;

• use the same board copper, solder process, and airflow;

• measure at the same terminals with the same probe method;

• apply the same preconditioning and acceptance limits;

• include samples from more than one production lot.

If exact normalization is impossible, state the mismatch beside the result. A transparent incomplete comparison is safer than a precise-looking table built from incompatible conditions.

Include the PCB in the verification

The diode is only one element of the surge path. Trace and via resistance create heating; interconnect inductance adds transient voltage; shared return impedance can lift the local ground at the protected IC. A fixture result therefore needs an assembled-board check.

Measure at two locations when practical: across the TVS terminals and at the vulnerable IC or rail. Use a probe arrangement whose loop is short enough for the event. If the waveforms differ materially, investigate placement and return geometry before assuming that a higher-power device will fix the problem.

Thermal observation is also useful during repeated events. Case temperature is not equal to junction temperature, but its trend can reveal accumulation and insufficient cooling between pulses. Record the measurement method, location, emissivity assumption if infrared imaging is used, and the time from pulse to measurement.

Build an application-specific acceptance rule

There is no universal percentage drift that suits every product. A high-impedance sensor input may be limited by leakage long before a power rail is affected. A tightly rated controller may be limited by residual voltage. An automotive or industrial design may also require defined lot, temperature, and traceability controls.

An acceptance rule should therefore state:

• the maximum allowed post-stress leakage at a named voltage and temperature;

• the allowable VBR and VC range under named test conditions;

• whether temporary functional disturbance is permitted during stress;

• the allowable package or solder-joint condition;

• the required sample and lot coverage;

• what constitutes a retest, failure analysis, or supplier corrective action.

The rule must be agreed before the test. Moving the limit after the result defeats supplier comparison.

What to request from a TVS diode manufacturer

For a new supplier, request the controlled datasheet revision, qualification scope, lot traceability, pulse-test method, raw or sample-level parameter data, and change-notification process. For a repetitive-surge application, add the exact sequence required by the product.

The ASIM TVS diode manufacturer page provides a route to product and selection information. Candidate selection should still be followed by a matched-condition test on the intended PCB. The decision should rest on the stated electrical limits and measured behavior, not on a manufacturer label or an isolated promotional number.

A short review checklist

Before signing the report, verify four points. First, the pulse can be reproduced from the stated conditions. Second, the measured nodes and equipment are identified. Third, pre-stress and post-stress data are available for each sample. Fourth, the acceptance rule matches the circuit's real vulnerability.

If any point is missing, the report may still be useful background information, but it is not yet evidence that the TVS is suitable for the repetitive event in the product.

Repetitive-Surge Data FAQ

Does a 600 W or 1,500 W rating define repetitive capability?

No. Peak pulse power is tied to a stated single-pulse condition. Repetitive use needs interval, duty, temperature, pulse count, and parameter-drift evidence.

Is “no short and no open” an adequate failure criterion?

Usually not. Leakage and clamp behavior can degrade before an open or short occurs. The acceptance rule should reflect the protected circuit.

Why test both the TVS terminals and the IC side?

PCB inductance and shared return impedance can add voltage between the TVS and the IC. The two measurements distinguish device behavior from layout behavior.