Walsin MLCC Environmental Compliance Document: 103 of 173 ECD URLs Point at the Same File

Walsin publishes a per-part MLCC environmental compliance document, and 103 of the 173 rows that carry an ECD URL point at the same file. We parsed all 173. Seventy name a distinct per-part document; the other 103 resolve to one shared placeholder with no part number in its filename.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds all 203 of Walsin Technology (Walsin) parametric export files and 28 Walsin datasheets, 451 pages. This post is written from one of those files — 00_ALL_MLCC_combined.xlsx, the 173-row enriched MLCC extract that is the only file in the set carrying an ECD URL column at all. Every part number below is real and checked against our master list. We did not fetch a single one of these URLs. This is a census of what the column contains, not a report on what the documents behind it say, and we will not tell you a document exists because a spreadsheet cell says it should.

How many Walsin MLCC rows carry a per-part environmental compliance document?

Seventy of 173. We counted every cell in the ECD URL column of 00_ALL_MLCC_combined.xlsx and all 173 are populated — the column is 100 percent filled, which is exactly why nobody checks it. Then we split each URL on the final slash and counted the filenames. 103 of the 173 resolve to one shared file whose name is a single letter. The other 70 name a part-specific document, and those 70 filenames are 70 distinct strings: one document per part, no repeats.

What the ECD URL column contains	Rows	Share of 173
A filename built from a specific orderable part code	70	40.5%
The shared single-letter placeholder, identical on every row	103	59.5%
Empty	0	0%
Distinct part-specific filenames among the 70	70	one per part

A fill-rate check on this column returns 100 percent and tells you nothing. A filename check returns 40.5 percent. We have not seen this counted anywhere, and it is the difference between believing you have a compliance document for every part and knowing you have one for two in five.

What does the ECD filename carry that the Part Number column does not?

Three things the export drops: a termination code, a packaging code, and a one-letter dimensional symbol. We took all 70 part-specific filenames, stripped the part number off the front, and read what was left. The remainder is always a two-letter code followed by a hyphen and two more characters. The two-letter code is CT on 65 of the 70, MT on 4 and LT on 1 — and the exported Part Number column shows none of them.

Exported part number	ECD document filename	Match / mismatch between the two forms
FT21B103M500	FT21B103M500CT-IT.pdf	Match on all six specification fields · mismatch: the export omits CT and the trailing -IT entirely
ST21B104K500	ST21B104K500CT-ID.pdf	Match on the specification code · mismatch: this row has no datasheet URL, so the ECD filename is the only orderable form we hold for it
TT21X106K100	TT21X106K100CT-TT.pdf	Match on the specification code · mismatch: the trailing pair is TT, not I-prefixed as on 62 of the 65 CT rows
S242B102K502	S242B102K502MT-PK.pdf	Mismatch: packaging pair reads MT, not CT, on this safety row, and the export states neither
HH15N0R4B500	HH15N0R4B500LT-IN.pdf	Mismatch: the only LT in all 70 filenames, and the export’s own columns do not reproduce it
2220B103K102	2220B103K102CT-IK.pdf	Match on the specification code · mismatch: CT and -IK exist only in the filename

Then we checked the last character of each trailing pair against the row’s own Symbol column. It matches on 70 of 70. FT21B103M500 carries Symbol T and its filename ends -IT; 2220B103K102 carries Symbol K and ends -IK; S242B102K502 carries Symbol K and ends -PK. That correspondence is exact across every part-specific filename in the file, and it means the Symbol letter is load-bearing in Walsin’s own document naming, not a spreadsheet leftover. What that letter encodes is a separate measurement, and we have made it separately.

Which MLCC series get a real ECD link, and which get none at all?

It splits hard by series. We grouped all 173 rows by the Series column and counted part-specific filenames in each. Two series return zero — High Temperature (HT) and soft termination SG, both 0 of 11. One returns everything — Microwave RF, 11 of 11. The rest sit between, and the spread is not explained by how new the series is or how many parts it holds.

Series in the enriched extract	Rows	Part-specific ECD	Shared placeholder	Datasheet URL
Microwave RF	11	11	0	11
Feed-through FT	8	7	1	8
Automotive MT (AEC-Q200)	11	8	3	11
Automotive soft-term ST	11	8	3	9
Middle and high voltage	11	7	4	11
High Q / low ESR HH	11	6	5	11
General purpose	11	5	6	11
Safety X1/Y2 S2	11	4	7	8
Automotive MG	11	3	8	11
Big sizes 1825 / 2220 / 2225	11	3	8	11
Soft termination SH	11	3	8	11
Low profile TT	11	2	9	11
Ultra-microwave UF	11	2	9	11
Ultra-small 01R5	11	1	10	11
High temperature HT	11	0	11	11
Soft termination SG	11	0	11	11

Read the HT row next to the RF row. Both are eleven parts in the same file, both have a complete datasheet URL, and one has eleven per-part compliance documents named and the other has none. If your qualification pack needs a document per part number, the series you picked decides whether that request is a lookup or a letter.

Can a part have an ECD document and no datasheet URL?

Yes, on two rows, and they are the two most useful rows in the file. ST21B104K500 and ST21B103K500 are both automotive soft-termination 0805 parts, both carry ST21B104K500CT-ID.pdf and ST21B103K500CT-ID.pdf as part-specific ECD filenames, and both have an empty DataSheet URL cell. They are 2 of the 5 rows in 173 with no datasheet URL. The other three are safety S2 rows — S242N100J502 is one — and all three carry the shared placeholder, so they have neither.

So the ECD column is not a subset of the datasheet column. We crossed the two: 68 rows have both, 100 have a datasheet URL and the placeholder, 2 have a part-specific ECD and no datasheet URL, and 3 have neither. A cross-reference tool that only reads the datasheet column loses the only per-part document reference those two automotive parts have. For how the datasheet column itself measures up, see Walsin MLCC datasheet URLs, 168 of 23,601 part numbers.

Does the ECD URL column exist anywhere else in Walsin’s 203 export files?

No. We opened the header row of all 203 files in our extract and searched for the column name. ECD URL appears in exactly one of them, the same 173-row file, alongside Walsin ID and DataSheet URL, which are also 1 of 203. By comparison, Symbol appears in 18 files, SPQ and Packing in 21 each — and SPQ and Packing are empty on every MLCC row we hold, so a present column is not a filled one.

Put against the catalogue as a whole, 173 rows is 0.05 percent of the 359,135 distinct part numbers our 203 files hold once the known QA test row is excluded. Walsin’s per-part environmental compliance document reference reaches two in five of one twentieth of one percent of the catalogue. That is the honest size of it, and nobody selling you a compliance package will say so. For what the full 203-file set can and cannot answer, see what Walsin’s 203 export files can and cannot answer.

What should you ask for when the ECD URL is the shared placeholder?

Ask by part number, in writing, and expect a document rather than a link. 103 of 173 rows give you nothing to click, and on those rows the export’s own Remark, Packing and SPQ columns are no help either — Packing and SPQ are empty on all 24,026 rows of the full MLCC export, which we counted separately.

1. Send the exact part number, not the series. We hold 28 Walsin datasheets, 451 pages. Ask for the one covering your part number and it will be in your inbox, not in a brochure. The per-part compliance document is a separate request and we will tell you plainly when a URL does not exist for it.
2. Cross the whole list 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. We will not tell you a part is equivalent. We will show you where it differs.
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.

The full range sits on the Walsin MLCC page. Our line runs from Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation, and nowhere else. Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong. (852) 2628 4777.

The short version

All 173 rows of Walsin’s enriched MLCC extract carry an ECD URL and 103 of them point at the same placeholder file, so the column’s 100 percent fill rate is worth nothing until you read the filenames. Seventy name a part-specific document and those 70 strings are distinct, one per part. The filename carries a termination and packaging code — CT on 65, MT on 4, LT on 1 — that the Part Number column drops, and its final character equals the row’s own Symbol value on 70 of 70. Two series return zero part-specific documents and one returns eleven of eleven. Two automotive soft-termination rows have a per-part ECD reference and no datasheet URL at all. The column exists in 1 of 203 export files and covers 173 of 359,135 part numbers. Qualification stays with you, and so does the decision about which document you will accept.

Send us the MLCC lines off your bill of materials and we will tell you, part number by part number, whether a per-part compliance document reference exists, whether it is the placeholder, and what we would have to ask Walsin for instead. And a question back: when your compliance folder shows a green tick against every line, has anyone opened the file behind it?

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Frequently asked questions

<!– wp:rank-math/faq-block {"questions":[{"id":"faq-question-01","title":"How many Walsin MLCC parts have a per-part environmental compliance document URL?","content":"Seventy of the 173 rows in 00_ALL_MLCC_combined.xlsx. All 173 cells are filled, but 103 of them resolve to one shared single-letter filename that carries no part number. The 70 part-specific filenames are 70 distinct strings, one document per part, with no repeats among them.”,”visible”:true},{“id”:”faq-question-02″,”title”:”Why does the ECD filename not match the exported part number exactly?”,”content”:”Because the export drops the termination and packaging codes. We measured all 70 part-specific filenames: the trailing code is CT on 65, MT on 4 and LT on 1, followed by a hyphen and two characters. None of those appears in the Part Number column, so the exported string is a specification code rather than an orderable one.”,”visible”:true},{“id”:”faq-question-03″,”title”:”Which Walsin MLCC series have no per-part compliance document in the export?”,”content”:”Two, both at zero of eleven sampled rows: the High Temperature HT series and the soft-termination SG series. At the other end, the Microwave RF series returns eleven of eleven. Both HT and SG carry a complete datasheet URL on all eleven rows, so the gap is in the per-part document reference only.”,”visible”:true},{“id”:”faq-question-04″,”title”:”Can a Walsin MLCC part have a compliance document and no datasheet URL?”,”content”:”Yes. Two rows do: ST21B104K500 and ST21B103K500, both automotive soft-termination 0805 parts. They are two of the five rows in 173 with an empty datasheet URL cell, and the only two of those five that carry a part-specific compliance document filename rather than the shared placeholder.”,”visible”:true},{“id”:”faq-question-05″,”title”:”Is the ECD URL column in every Walsin export file?”,”content”:”No. We checked the header row of all 203 files in our extract. ECD URL appears in exactly one of them, the 173-row enriched MLCC file, alongside Walsin ID and DataSheet URL. The 24,026-row full MLCC export carries none of the three, so the column covers 0.05 percent of the catalogue.”,”visible”:true},{“id”:”faq-question-06″,”title”:”Did Venatech open these compliance documents?”,”content”:”No, and we will not imply otherwise. This is a census of a spreadsheet column, counted from the filenames in it. We have not fetched any of the 70 part-specific URLs and make no statement about what any of those documents contains, which revision it is, or which regulatory regime it addresses.”,”visible”:true},{“id”:”faq-question-07″,”title”:”What should I request if my part falls in the 103?”,”content”:”Request the compliance document for the exact part number in writing, and ask for the full orderable code with its termination and packaging suffix at the same time. We hold 28 Walsin datasheets, 451 pages, and will send the one covering your part. Where no per-part document reference exists, we will say so rather than substitute a series document.”,”visible”:true}],”listStyle”:””,”titleWrapper”:”h3″,”titleCssClasses”:””,”contentCssClasses”:””,”sizeSlug”:””} –>

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