Automotive Y Capacitor for Germany: 23 of 929 Walsin Disc Rows Say Auto, and All 23 Have a Same-Size Commercial Twin

We searched all 929 rows of Walsin’s ceramic disc capacitor export for an automotive marker. Exactly 23 carry one, and it is the word “Auto” inside a series name. Every one of those 23 has a commercial part of the same dielectric, capacitance, tolerance and body size, differing by a single digit in the code.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the ceramic disc capacitor parametric export published by Walsin Technology (Walsin) — Walsin_DiscCap_ALL.xlsx, 929 rows — and no disc capacitor datasheet of any kind. None of the 28 Walsin datasheets we hold, 451 pages, covers this line. This post is written for a German engineer putting a Y capacitor across an isolation barrier in a vehicle, and it is written from that one file, so every specification claim is flagged and we link only to Walsin’s own site for specifications. Every part number is real.

How many of Walsin’s 929 disc capacitors are marked automotive?

23. We searched the full text of every cell in Walsin_DiscCap_ALL.xlsx for an automotive marker and found exactly one token: the word “Auto”, appearing 23 times, always at the end of a Series string reading “Safety Certificated Caps X1/Y2_(AC series) Auto”. That is 2.5% of the line, and it is the whole of the automotive signal. All 23 share one part-number structure and one rating.

Marker we searched for	Occurrences in 929 rows	Where it appears	Match / mismatch against a German automotive selection
Auto	23	Series column only	Mismatch — a word in free text, not a field
automotive	0	nowhere	Mismatch
AEC	0	nowhere	Mismatch
Q200	0	nowhere	Mismatch
qualif (any form)	0	nowhere	Mismatch
A grade or qualification column	0 of 11 columns	no such header exists	Mismatch — the export has no field for it

So the question “is this disc capacitor automotive grade?” cannot be answered from the data at all. It can only be answered from a four-letter substring in a label. We have not seen this counted anywhere, and it is the first thing we would tell a German tier-1 or tier-2 before they put a part number on a drawing.

Does the word AEC-Q200 appear anywhere on this line?

No — zero occurrences across all 929 rows and all eleven column headers, and zero pages across the 451 we hold, because we hold no page for this line at all. AEC-Q200 is named on 8 of our 28 Walsin datasheets, 73 pages, and every one of those is a multilayer chip part, not a leaded disc. Walsin’s own wording on those documents is compliant and qualified to, never certified, and we do not upgrade it; the disc line does not even get that far.

That matters more here than on a chip part, because a Y capacitor is a safety component and a German tier-1 package will ask for a qualification report by part number. We hold no qualification report for any Walsin part number, on any line. The report to ask for, and what it is not, is set out in AEC-Q200 compliant is not certified.

What actually differs between the automotive part and its commercial twin?

One digit, one word and a suffix on a text field. We matched each of the 23 Auto parts against the 57 standard X1/Y2 parts at the same rating, on dielectric, capacitance code, tolerance and body code. All 23 found an exact same-size twin. Not one of the 23 is unique in the range on any published field.

Automotive part	Commercial twin	Dielectric	Capacitance	Tolerance	Body code	UR on the Auto part	UR on the twin	Match / mismatch
YP7AC101K060	YP1AC101K060	YP (Y5P)	100 pF	±10%	060	X1-440Vac/Y2-300Vac 1500Vdc	X1-440Vac/Y2-300Vac	Match on all five selection fields, mismatch only on the 7/1 digit and the trailing Vdc figure
YP7AC821K080	YP1AC821K080	YP (Y5P)	820 pF	±10%	080	X1-440Vac/Y2-300Vac 1500Vdc	X1-440Vac/Y2-300Vac	Match on all five, mismatch on the digit and the Vdc figure
YU7AC332M100	YU1AC332M100	YU (Y5U)	3300 pF	±20%	100	X1-440Vac/Y2-300Vac 1500Vdc	X1-440Vac/Y2-300Vac	Match on all five, mismatch on the digit and the Vdc figure
YU7AC472M120	YU1AC472M120	YU (Y5U)	4700 pF	±20%	120	X1-440Vac/Y2-300Vac 1500Vdc	X1-440Vac/Y2-300Vac	Match on all five, mismatch on the digit and the Vdc figure
YV7AC472M100	YV1AC472M100	YV (Y5V)	4700 pF	±20%	100	X1-440Vac/Y2-300Vac 1500Vdc	X1-440Vac/Y2-300Vac	Match on all five, mismatch on the digit and the Vdc figure
YV7AC103M140	YV1AC103M140	YV (Y5V)	10,000 pF	±20%	140	X1-440Vac/Y2-300Vac 1500Vdc	X1-440Vac/Y2-300Vac	Match on all five, mismatch on the digit and the Vdc figure

The structural rule is simple and worth knowing. Character three of a Walsin disc part number is the rating code: 1 on the 57 standard X1/Y2 parts at 440 Vac, 7 on the 23 Auto parts at the same 440 Vac. 0, 5 and 7 cover the other rating steps. Change that one digit and the part moves between commercial and automotive labelling with nothing else on the row changing.

Two consequences follow. First, a buyer who orders YP1AC101K060 when the drawing says YP7AC101K060 receives a part that is identical on every field the export publishes and is not the part on the drawing. Second, there is no incoming-inspection check that catches it, because the export gives you nothing to measure the difference against.

Which Y class can a German 440 Vac design have, and what decides it?

The X1 rating decides it, not the designer. We tabulated all 367 safety certificated rows by X1 voltage and Y class, and the mapping is rigid. At 440 Vac you get Y2 and nothing else — all 137 parts, the 23 Auto ones included. At 400 Vac you get Y1 and nothing else, on 112 parts. Only at 500 Vac does Walsin publish both.

X1 rating	Y1 part numbers	Y2 part numbers	Match / mismatch if your specification names a Y class first
400 Vac	112	0	Mismatch — Y2 is not available at this X1 rating
440 Vac	0	137	Mismatch — Y1 is not available, and this is the only step with automotive parts
500 Vac	54	49	Match — the only step where the choice is yours
760 Vac	15	0	Mismatch — Y1 only, and the whole AS series

So a German design that has fixed on a Y2 classification and a 440 Vac X1 rating has 137 candidates, of which 23 carry the Auto label. A design that wants Y1 has to leave 440 Vac altogether. The class mechanics are in X1/Y1 against X1/Y2 safety capacitors, and the line is on the Walsin disc capacitor page.

One defect to carry into your own review: YP1AC101K060 is listed as an X1/Y2 part while pointing at the X1/Y1 documentation. It is also the exact commercial twin of the first Auto part in the table above, which is an unhappy coincidence for anyone cross-referencing that position.

What documentation exists for an automotive disc capacitor, and what does not?

For this line, almost nothing, and we will say so before you find out at the audit. Zero of the 929 disc rows carries a certificate number, zero of our 451 pages covers the line, and the export has no column for RoHS, REACH, lifecycle, operating temperature or qualification status. We counted all of it. Our own census of the certificate gap on this line is in safety capacitor certificate numbers, zero of 929 disc rows.

What we do hold, and what a German quality engineer can check without taking our word for it: we are an authorised Walsin Technology distributor in Hong Kong, confirmable with Walsin. UL file E182369 is in UL’s public database — it covers the surface-mount safety capacitor series, not this one, and we tell you which is which rather than letting a certificate number do work it does not do. We hold 28 Walsin datasheets, 451 pages, and we will send the one covering your part number or tell you the same day that none exists. We hold neither ISO 9001 nor IATF 16949, and we say so here rather than let a supplier questionnaire establish it.

Lot and date-code traceability, a certificate of conformity per shipment on request and original sealed Walsin packaging are our commitments as the authorised channel. They are not lifted from a manufacturer document and we will not present them as though they were.

What should a German buyer ask for before putting this on an AVL?

The drawing and the qualification position, in writing, for the exact twelve-character code — including the third character. We will not tell you a part is equivalent. We will show you where it differs, and on this line the honest statement is that the automotive part and the commercial part differ on nothing we can show you.

1. Cross the whole safety and mains-input block in one pass. Paste up to 500 part numbers or drop your Excel or CSV into the free cross-reference tool, filter by commercial or automotive grade, and read every stated difference rather than a claimed match.
2. Ask us which document governs the line before you ask for a price. For the disc capacitor line the answer today is none, and you get that answer the same day.
3. Check what is physically in Hong Kong on ready stock — 1,125 part numbers as at 23 September 2026, a dated snapshot and not a live feed. No disc capacitor appears in it.

Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong. (852) 2628 4777.

The short version

23 of Walsin’s 929 ceramic disc capacitor rows carry an automotive marker, and that marker is the word “Auto” at the end of a series name. The strings AEC, Q200, automotive and qualification appear zero times in the file, and no column exists for grade or qualification status. All 23 Auto parts have a commercial twin of the same dielectric, capacitance, tolerance and body size; the published differences are one digit in the code, one word in a text field and a trailing Vdc figure we cannot interpret. At 440 Vac the Y class is fixed at Y2 across all 137 parts. Zero of the 929 rows carries a certificate number, zero of our 451 pages covers the line, and we hold no disc capacitor datasheet at all. That is the whole evidential position and we would rather state it than dress it up.

Send us the Y capacitor positions off your German bill of materials and we will return, for each one, the exact Walsin code, the twin it is one digit away from, and a plain statement of which documents exist and which do not. Qualification stays with you. And a question back: if the only thing marking your automotive Y capacitor as automotive is a word in a spreadsheet, what is your incoming inspection actually checking?

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Frequently asked questions

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