A TDK 350 V mid-voltage capacitor has no Walsin counterpart: of 23,601 distinct Walsin MLCC part numbers we parsed, 0 are rated 350 V, 9 are rated 400 V and 24 are rated 450 V. For a United States EV charger maker the cross moves up a rung, and 1 part at 450 V is on our Hong Kong shelf.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the Walsin Technology (Walsin) MLCC export of 24,026 rows, 23,601 of them distinct part numbers. This post is for a design engineer or buyer at a United States maker of Level 2 or DC fast chargers who has TDK C-series mid-voltage capacitors on a bill of materials and wants a second source. Every Walsin part number below is real and every count is ours. It makes no claim for any automotive or vehicle use. Where it states a market fact it names the source, its date and the day we read it.
Why does a charger buyer care about one voltage code?
Because the network keeps growing and the bill of materials grows with it. Paren’s quarterly report, as covered by EV Infrastructure News on 13 October 2026, put United States fast-charging ports above 80,000 for the first time and counted 4,106 ports added in the third quarter across 664 new stations. We read the article on 23 October 2026.
The same article reports that Tesla held 49.3 percent of all fast-charging ports, down from 54.3 percent a year earlier. We use none of that for the parts argument. Our own view, labelled as ours: every new station adds a mains-side filter and a DC link, and the capacitor rung chosen for a 240 V supply is the first decision where a second source runs out of choices.
Which TDK mid-voltage codes does Walsin have a rung for?
Four of TDK’s five, and Walsin adds three rungs TDK’s catalogue does not list. TDK’s commercial mid-voltage MLCC catalogue, document code 20260918 and dated September 2026, lists five voltage codes: 2A is 100 V, 2E is 250 V, 2V is 350 V, 2W is 450 V and 2J is 630 V. We counted the Walsin rungs against them.
| TDK code | TDK voltage | Walsin code | Distinct Walsin parts | Class II among them | Stocked, 23 September 2026 | Match / mismatch |
|---|---|---|---|---|---|---|
| 2A | 100 V | 101 | 3,089 | 859 | 56 | Match on rung |
| none listed | none | 201 (200 V) | 1,041 | 295 | 13 | Walsin-only rung |
| 2E | 250 V | 251 | 1,821 | 500 | 50 | Match on rung |
| 2V | 350 V | none | 0 | 0 | 0 | Mismatch: no Walsin part at 350 V |
| none listed | none | 401 (400 V) | 9 | 9 | 0 | Walsin-only rung, X7R in 1206 and 1210 |
| 2W | 450 V | 451 | 24 | 24 | 1 | Match on rung, but only 24 parts |
| none listed | none | 501 (500 V) | 1,120 | 346 | 20 | Walsin-only rung |
| 2J | 630 V | 631 | 944 | 383 | 31 | Match on rung |
We have not seen this counted anywhere: the one TDK mid-voltage rung with no Walsin part is the one that sits just above a United States 240 V supply peak. Class II here means X7R, X5R, X7S, X7T, X6S and X8R. TDK’s own list is the incumbent side, so confirm it against the current catalogue.
What does a 240 V supply do to the choice of rung?
It puts the peak at about 339 V, which leaves a 350 V part almost no headroom. A 240 V rms supply has a peak of 240 times 1.414, or 339 V, so a 350 V rung sits 11 V, or 3 percent, above the peak. If you apply an 80 percent working limit, which is our assumption and not a rule, you need a rating of at least 424 V.
That limit points to 450 V, where Walsin has 24 parts, or to 500 V, where it has 1,120. Our post on MLCC DC bias and voltage derating explains why a high-voltage X7R part loses capacitance as the bias rises, and the datasheet curves, not the rung, decide the real value. At 1206 and 100 nF in X7R, the ladder is thin: one part number at 400 V (1206B104K401), five at 450 V including 1206B104K451, and none at 500 V or 630 V. A DC fast charger on a 480 V three-phase supply rectifies to a peak near 679 V; our earlier post on EV charger capacitors above 1,000 V covers that end.
How do the two TDK catalogue examples cross to Walsin?
One crosses on every field and one gives up its dielectric and its thickness. TDK’s catalogue prints two example numbers, C1608C0G2A101J080AA and C5750X7S2A226M280KB; we crossed both against all 23,601 part numbers. The first has a Walsin part that matches on size, dielectric, voltage, capacitance, tolerance and thickness. The second has none that matches on dielectric.
| TDK incumbent | Walsin candidate | Series | Thickness (export) | Stocked | Match / mismatch |
|---|---|---|---|---|---|
C1608C0G2A101J080AA (0603, C0G, 100 V, 100 pF, ±5%, 0.80 mm) |
0603N101J101 |
General purpose | 0.80 ± 0.07 mm | No | Match on all six fields |
C1608C0G2A101J080AA |
MT18N101J101 |
AEC-Q200 MT | 0.80 ± 0.07 mm | No | Match on six; mismatch on series, an automotive-compliant line |
C5750X7S2A226M280KB (2220, X7S, 100 V, 22 µF, ±20%, 2.80 mm) |
2220B226M101 |
Big sizes | 3.10 ± 0.30 mm | No | Match on size, voltage, capacitance, tolerance; mismatch on dielectric (X7R against X7S) and on thickness (0.30 mm nominal taller) |
| 1206, X7R, 100 nF, 350 V brief (no TDK number) | 1206B104K401 |
Middle to high voltage | 1.60 ± 0.20 mm | No | Match on size, dielectric, capacitance; mismatch on voltage, 400 V against 350 V |
| 1206, X7R, 100 nF, 350 V brief | 1206B104K451 |
Middle to high voltage | 1.60 ± 0.20 mm | No | Match on size, dielectric, capacitance; mismatch on voltage, 450 V against 350 V |
Walsin’s export has no X7S row at 2220; its 21 X7S rows sit at 0201 to 0805. TDK states in the catalogue that its products are not designed or warranted for the applications it lists, which include transportation equipment such as cars, and it tells the reader to contact TDK for such use. The catalogue lists wireless charging units, DC-DC converters and inverters among its intended applications. Whether a charger counts is a question for TDK and your compliance team, not for us. Confirm thickness and tolerance against both datasheets.
What do we hold in stock at 400 V and above?
Thin cover at the rungs a charger needs. We counted our stock list as at 23 September 2026, 1,125 part numbers, of which 764 match an MLCC export row: 0 are rated 350 V or 400 V, 1 is rated 450 V (1210B274K451, 270 nF X7R), 20 are rated 500 V and 31 are rated 630 V.
None of the 28 Walsin datasheets we hold, 451 pages, names an EV charger or an electric vehicle charging use. The ready stock page shows what is held in Hong Kong as a dated snapshot, never live-synced, and we quote part-number counts, never piece counts. For 1206 at 100 nF and 450 V, the stocked answer does not exist, so it is a factory order; ask us before you plan a build. Our post on how to cross-reference an MLCC sets out the method we follow.
How can Venatech help a United States EV charger maker?
By crossing the TDK number you already have, stating the differences, and telling you what is missing. Venatech Limited is an authorised Walsin distributor in Hong Kong. Walsin is our only authorised line, and the other lines we supply are Stackpole and Viking.
- Cross-reference. Paste a TDK C-series number into the free cross-reference tool, which decodes 18 manufacturers’ part numbers across 800,000+ crossable parts, and read each Walsin candidate with match and mismatch stated field by field.
- BOM check. Upload a power-board bill of materials, up to 500 part numbers or an Excel or CSV file, to /bom/.
- Ready stock. The ready stock list is a Hong Kong snapshot dated 23 September 2026.
- Service. Hong Kong-based, small lots, cross-referencing help, and a quote requested through the site. Our address is Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong, telephone (852) 2628 4777.
A worked example from our own export: a 100 nF, 1206, X7R brief at 350 V maps to 1206B104K401 at 400 V or 1206B104K451 at 450 V, neither stocked. Our MLCC range lists the families. Confirm against both datasheets and qualify in your own circuit.
The short version
Walsin has 0 parts at 350 V, 9 at 400 V and 24 at 450 V, against TDK’s 350 V and 450 V codes. A United States 240 V supply peaks near 339 V, so the 350 V rung is the one a charger design reaches for and the one a Walsin cross cannot answer. One 450 V part is on our shelf.
Send us the mid-voltage capacitor from one charger power board and we will return the Walsin candidates with the voltage step and every other difference stated. When the cross forces you up a rung, which gives way first, the footprint or the margin?
Sources
Fetched 23 October 2026. The market and catalogue statements above come from these pages; the part data comes from our own Walsin export and stock list.
- EV Infrastructure News, “US fast charging network surpasses 80,000 ports in Q3 2026, Tesla’s market share dips below 50%”, 13 October 2026, reporting Paren’s quarterly report: https://www.evinfrastructurenews.com/charging-installation/us-fast-charging-network-q3-2026-tesla-market-share
- TDK, commercial mid-voltage MLCC catalogue, document code 20260918, September 2026: https://product.tdk.com/system/files/dam/doc/product/capacitor/ceramic/mlcc/catalog/mlcc_commercial_midvoltage_en.pdf
Frequently asked questions
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Does Walsin make a 350 V MLCC?
No. We parsed all 23,601 distinct Walsin MLCC part numbers and none is rated 350 V. The ladder goes 250 V, 400 V, 450 V, 500 V and 630 V. TDK’s 2V code is 350 V, so a cross has to move up a rung and state the voltage difference.
What does TDK’s 2V mean in a C-series number?
It is the rated-voltage field, and 2V is 350 V in TDK’s commercial mid-voltage catalogue dated September 2026. The same catalogue gives 2A as 100 V, 2E as 250 V, 2W as 450 V and 2J as 630 V. Check the current catalogue before you rely on a code.
What voltage rung does a 240 V charger supply need?
A 240 V rms supply peaks at about 339 V. With an 80 percent working limit, which is our assumption, the rating needs to be 424 V or more, which points to 450 V or 500 V. Your derating policy and the datasheet bias curves decide. Walsin has 24 parts at 450 V.
Do you hold 450 V capacitors in Hong Kong stock?
One. As at 23 September 2026 we hold 1210B274K451, a 270 nF X7R part at 450 V, among 764 stocked MLCC part numbers. Nothing is stocked at 350 V or 400 V. The ready stock page shows what is held now, and other values are a factory order.
Is the TDK catalogue approved for EV chargers?
We cannot say. TDK’s catalogue says its products are not designed or warranted for the applications it lists, which include transportation equipment such as cars, and refers such use to TDK. Ask TDK and your compliance team whether a charger counts. We give no compliance advice.
Can I cross a TDK C-series number automatically?
Yes. Paste it into the free cross-reference tool, which decodes 18 manufacturers’ part numbers, and read the Walsin candidates with match and mismatch fields. Upload a whole bill of materials to the BOM page. Confirm against both datasheets and qualify in your own circuit.