Is the TVR20561KSW Still in Production?

Yes — the series datasheet is current and lists this exact order code as an orderable model. The TVR-D document is the 2025.12 edition, and its 20-D electrical table carries TVR20561KSW against certified model TVR20561-D.

The code itself tells you which grade you have. The W suffix marks the high-surge series with RoHS compliance, so a part ending in W is the surge-capable version of that voltage and size, not the standard one.

That matters for substitution. What sends buyers looking for an alternative is usually sourcing or second-sourcing rather than discontinuation, and the grade is the thing worth preserving: a standard-series disc at the same voltage does not carry the same surge rating.

If you are comparing against another maker's part, the question to ask first is which grade it belongs to — the answer changes what the rest of the numbers mean.

What Can Replace the TVR20561KSW?

At the steady-state and clamping level, three parts are interchangeable; at the surge level, the original has roughly twice the capability of the other two. The comparison below is built from each manufacturer's own datasheet.

Read the first four rows and the parts look like the same component. Same nominal voltage, same tolerance window, same continuous AC rating, clamping within one percent of each other.

Then read the surge rows. On the identical 8/20 µs waveform the original carries 13,000 A against 6,500 A for both alternatives. That isn't a rounding difference — it's the reason this part exists in the high-surge series.

One more difference worth flagging: the continuous DC rating is not the same across a 560 V part. Thinking publishes 450 V where Bourns and Vishay publish 460 V, even though the varistor voltage and the AC rating match.

The question also shows up in the wild on this exact part number. One thread starts with a failed 20D561K pulled out of a UPS, asking whether every parameter has to match or only the important ones. The answer named the disc diameter and the 1 mA voltage, then stopped.

Why the Joule Numbers Don't Line Up

Because one datasheet measures energy on an 8/20 µs pulse and the others use a 10/1000 µs pulse. Those two waveforms are not variations of one test; they are different stresses.

The bars are scaled to the largest figure in the chart, not to a shared test. What the picture is meant to make obvious is which numbers sit on the same ruler and which one does not.

A 10/1000 µs pulse is roughly fifty times longer than an 8/20 µs pulse. A device that absorbs 220 J over a short impulse and one that absorbs 475 J over a long one are being asked different questions.

So compare the alternatives on the rating that is stated the same way. Peak current is published on an 8/20 µs basis by all three manufacturers, which makes that the row to trust.

That is the comparison to make before anything else. If the application never sees more than a few hundred amps of surge, both alternatives are comfortable. If it was specified against the original's rating, neither substitute carries it.

The Migration Checklist

Six checks, in this order, and the first three decide whether the swap is even possible. We run the same list before quoting a replacement.

Note what the list leaves out: the joule figure on its own. It's the number buyers reach for first and the one that most often misleads, because it travels without its test condition.

One more candidate is worth mentioning. The TDK EPCOS S20K350 is the cross-reference most often quoted for this part. Its ratings have to be taken from its own datasheet, like any other — the series exists in more than one surge grade, and the grade decides the numbers.

Where to Buy TVR20561KSW Replacements

From ICMASS — the original and the cross-referenced alternatives, quoted against the same requirement. We keep the Thinking high-surge table next to the Bourns and Vishay datasheets, so a substitution is checked rather than assumed.

If the surge rating is what your design depends on, tell us the waveform you are protecting against — 8/20 µs or 10/1000 µs — and we will confirm whether a substitute carries it or whether the original is the only part that does.

We also quote the lead-form variants, since the same die is sold straight, kinked and taped, and the footprint usually decides which one you can use.

Send us the line voltage, the surge you expect and the space you have, and we will confirm the equivalent and quote on your quantity.

When to Stay With the Original

Stay with the Thinking part when the surge rating is the design margin. That is the one row where the alternatives do not reach it.

• The specification was written around a 13,000 A 8/20 µs capability. Both substitutes publish 6,500 A.
• Agency approvals for your market were granted against the original part number and re-qualifying is not worth the saving.
• The board is already released and the substitution would touch a safety-related rating.

When the Substitutes Are the Right Call

Switch when the surge requirement is modest and availability or second-sourcing is the driver. Electrically, the parts line up closely.

• The application sees surge currents well inside 6,500 A, which covers most power-supply and consumer protection designs.
• You are second-sourcing a single-supplier line and the alternatives' continuous and clamping ratings already fit.
• You need a capacitance figure. Thinking's 20-D table does not publish one, while Bourns and Vishay do.
• Your purchasing side wants two qualified vendors on the drawing.

Frequently Asked Questions About TVR20561KSW Replacements

Q1: What is a direct replacement for the TVR20561KSW?

A: The Bourns MOV-20D561K or the Vishay VDRS20W350B, if your surge requirement is under 6,500 A. Both publish the same 560 V varistor voltage, the same 350 V a.c. continuous rating and clamping within 10 V of the original.

Q2: Are they pin-to-pin compatible?

A: Mechanically yes, in the 20 mm disc format — but check the lead form. Each manufacturer codes lead style and packaging at the end of its part number, and a straight lead does not drop into a footprint drawn for a kinked one.

Q3: Why do the energy ratings differ so much?

A: Because two different pulse widths are in play. The original and the Vishay part are rated on a 10/1000 µs pulse; the Bourns figure is quoted on an 8/20 µs pulse. Those numbers measure different stresses.

Q4: Which rating should I compare instead?

A: Peak surge current on the 8/20 µs waveform. All three manufacturers state it the same way, and it separates the parts cleanly: 13,000 A against 6,500 A.

Q5: Is the clamping voltage a problem when substituting?

A: No — the three parts clamp within 10 V of each other. 930 V, 925 V and 920 V at 100 A. Whatever survives the original's clamping will survive theirs.

Q6: Can I substitute a lower-voltage varistor instead?

A: Only if the continuous rating still covers your line. A lower code raises the clamping voltage and lowers the continuous rating, so the protection window shifts at both ends. Move up or down the ladder deliberately, not by availability.

Q7: Are the agency approvals the same?

A: Each manufacturer holds its own approvals against its own part number. They are not transferable, so if your product is certified against a specific varistor, confirm the substitute is covered before you change the bill of materials.

Q8: Does the TVR20561KSW have a published capacitance?

A: Not in the 20-D electrical table. The Bourns and Vishay equivalents publish 852 pF and 660 pF at 1 kHz. If capacitance matters to your circuit, that alone can settle which substitute to use.