Walsin MLCC Duplicate Part Number: 132 of 8,330 Appear Twice, and 124 Disagree on Thickness

A walsin mlcc duplicate part number is not rare: 132 of the 8,330 distinct part numbers in Walsin’s General Purpose export appear on two or three rows, 269 rows in total. We checked all 132, and zero disagree on capacitance, tolerance or voltage — but 124 disagree on thickness.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the full parametric export from Walsin Technology (Walsin). This post is measured from one file, 07_General_Purpose.xlsx, 8,467 rows. Every part number below is real, and every count is a count of part numbers, not pieces. We parsed the whole file and we have not seen this counted anywhere else.

How many Walsin general purpose MLCC part numbers appear more than once?

One hundred and thirty-two. We counted the occurrences of every string in the Part Number column across all 8,467 rows: 8,330 are distinct, and 132 of those 8,330 show up on more than one row — 127 twice and 5 three times, for 269 rows and 137 rows more than a one-row-per-part count would expect. That 137 is the number a reader sees quoted elsewhere on this file; it counts excess rows, not distinct duplicated part numbers, and the two are not the same figure.

Measure	Count	Share of 8,467 rows
Distinct part numbers	8,330	98.4%
Part numbers appearing exactly once	8,198	—
Part numbers appearing twice	127	—
Part numbers appearing three times	5	—
Rows belonging to a duplicated part number	269	3.2%
Excess rows beyond one-per-part	137	1.6%

A reader building a BOM check or a part-number lookup off a naive nunique() call gets 8,330 and stops there. A reader who joins on the raw column gets 269 hits for 132 queries and has to decide, row by row, which one is right.

Do any of the 132 duplicated part numbers disagree on capacitance, tolerance or voltage?

No. We checked the Capacitance, Tolerance, Rated Voltage, Dielectric, Size and Series columns on every one of the 132 duplicated part numbers, and zero rows disagree on any of them. Every pair or triple of rows sharing a Part Number string agrees on exactly what the part is electrically — the same capacitance value, the same tolerance band, the same rated voltage, the same dielectric. That is the fact that keeps this in the physical-dimension category rather than a true specification conflict: a cross reference built on these six fields would return a correct answer every time, because the six fields a cross actually matches on never disagree.

What actually differs between the duplicate rows, then?

Thickness, mostly. We grouped the diffs by which columns changed across each duplicated part number’s rows:

Fields that differ	Part numbers affected	Share of 132
Thickness (T) and Symbol only	2	1.5%
Thickness, Symbol and Remark	75	56.8%
Length, width, thickness, Symbol and Remark	39	29.5%
Length, width, thickness and Symbol	6	4.5%
Length, width, thickness, Symbol, Remark and Termination	1	0.8%
Remark only — every dimension and the Symbol match	8	6.1%

Match / mismatch against the requirement “one Part Number string identifies one physical part”:

Part number	Rows	T values across rows	Symbol values	Match / mismatch
0805B102K500	3	0.60±0.10 / 0.80±0.10 / 1.25±0.10 mm	A, B, D	Mismatch — three thicknesses, one string
0805N123J160	3	0.85±0.10 / 1.25±0.10 / 1.25±0.20 mm	T, D, I	Mismatch — three thicknesses, one string
1206X106K250	2	1.60±0.20 / 1.60+0.30/-0.10 mm	G, P	Mismatch — also the only pair where Termination differs
0402B104M500	2	0.50±0.05 / 0.50±0.20 mm	N, E	Mismatch — same nominal thickness, different tolerance band
0603S475M6R3	2	0.80+0.15/-0.10 mm on both rows	X, X	Match — identical in every dimension; one row carries a note the other does not

The thickness figure itself never carries the Symbol letter. A reader pulls 0805B102K500 off this file and gets a single capacitance, a single voltage and three physical thicknesses with no way to tell, from the Part Number column alone, which thickness ships.

Are any of the 132 duplicates genuinely harmless?

Eight of them, yes — 6.1%. On those eight, every dimension column and the Symbol column are identical between the rows, and the only difference is that one copy of the row carries the note “Customized product. Please contact WTC local representative.” or “It is for customize part no.” and the other does not. 0603S475M6R3 is one of them. Those eight rows are true restatements: the same orderable identity, logged twice, with an annotation attached to only one copy.

The other 124 of 132 are not restatements. They are 124 cases where the Part Number column alone cannot tell two or three physically different parts apart. We counted this distinction because the difference matters for anyone pasting this file into a cross reference: eight duplicates are noise and can be deduplicated safely; 124 cannot be deduplicated without losing information about which thickness, and in 46 cases which length and width, the string actually refers to.

What is the Symbol column doing that the Part Number column does not?

Carrying the one piece of information that actually disambiguates a duplicated row. On every one of the 124 thickness-variant duplicates, the Symbol value is different on every row for that part number, and it is the only column that is never NaN and never repeated within the group. Walsin’s own general purpose datasheet, WTC_MLCC_General_Purpose.pdf per INDEX_MLCC_series.csv, states a capacitance range of 0.1 pF to 220 µF and a voltage range of 6.3 V to 100 V for the series — and separately, we measured 40 rows in the export at 4 Vdc, below that stated floor, which is a different gap in the same file and one we are not resolving here either.

Does a duplicate part number break a cross reference or a BOM check?

Not on the fields that decide a match, but it changes what “one result” means. A BOM check that counts distinct part numbers correctly reports 8,330 for this file. A cross reference that returns “a match” for 0805B102K500 is returning one electrical answer backed by three physical candidates, and the tool cannot pick between 0.60 mm, 0.80 mm and 1.25 mm thickness without more than the string itself. We will never call any of the three “equivalent” to each other — they are the same capacitance, tolerance and voltage, and three different physical parts, and a buyer qualifying a footprint needs to know which one is actually on the way.

What should a buyer do with a Walsin MLCC duplicate part number?

Ask for the thickness before you assume one. If a Walsin general purpose MLCC part number you are crossing or reordering is one of the 132 on this list, treat the Symbol letter as load-bearing, not cosmetic, and request it explicitly rather than taking the first row a spreadsheet filter returns.

1. Cross your BOM through the free cross-reference tool. It decodes 18 manufacturers’ part numbers and matches against 800,000+ crossable Walsin part numbers, and it will show you every candidate row rather than silently picking one.
2. Check what is physically in Hong Kong on ready stock, a dated snapshot as at 23 September 2026, before you commit a thickness assumption to a production order.
3. Send us the exact part number and we will quote you the Symbol letter and the thickness that goes with it, rather than the one a naive lookup happens to return first.

For how a Walsin part number is built in the first place, see How to read a Walsin MLCC part number. For the related case where the printed string and the orderable code are not the same thing, see Why Walsin part numbers do not paste into your BOM. The full range is on the Walsin MLCC page.

The short version

We parsed all 8,467 rows of 07_General_Purpose.xlsx and found 8,330 distinct part numbers. 132 of those 8,330 appear on more than one row — 269 rows in total — and zero of the 132 disagree on capacitance, tolerance, rated voltage, dielectric, size or series. Eight are genuine restatements, identical except for a remark. The other 124 use one string to name two or three physically different thicknesses, distinguished only by a Symbol column that the Part Number string itself does not carry. We have not seen this counted anywhere else, and it changes what “one part number” means on 124 lines of this file.

Send us a Walsin general purpose part number from this list of 132 and tell us which thickness your footprint needs — we will tell you the Symbol letter that goes with it rather than leaving you to guess from the string alone.

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Frequently asked questions

<!– wp:rank-math/faq-block {"questions":[{"id":"faq-question-01","title":"How many Walsin general purpose MLCC part numbers appear more than once in the export?","content":"132 of 8,330 distinct part numbers. We counted every occurrence in the Part Number column across all 8,467 rows of 07_General_Purpose.xlsx: 127 part numbers appear on two rows and 5 appear on three rows, for 269 rows in total and 137 rows more than a strict one-row-per-part count.”,”visible”:true},{“id”:”faq-question-02″,”title”:”Do the duplicate rows disagree on capacitance, tolerance or rated voltage?”,”content”:”No. We checked all six identity fields — capacitance, tolerance, rated voltage, dielectric, size and series — on every one of the 132 duplicated part numbers, and none disagree on any of them. The disagreement is entirely in the physical dimension fields, not the electrical ones.”,”visible”:true},{“id”:”faq-question-03″,”title”:”What field actually differs between the duplicate rows?”,”content”:”Thickness, on 124 of the 132. Forty-six also disagree on length and width. A Symbol column carries a different letter on each row and is the only field that reliably distinguishes the variants, but it is not part of the Part Number string the row is keyed on.”,”visible”:true},{“id”:”faq-question-04″,”title”:”Are any of the 132 duplicates safe to simply remove?”,”content”:”Eight of them, yes. On those eight every dimension and the Symbol value match exactly between the rows, and the only difference is a remark present on one copy and absent on the other. The remaining 124 cannot be safely deduplicated without losing the thickness, and in some cases the length and width, that the Symbol letter was tracking.”,”visible”:true},{“id”:”faq-question-05″,”title”:”Does this affect whether a cross reference returns the right electrical match?”,”content”:”No, because the fields a cross matches on — capacitance, tolerance, voltage and dielectric — never disagree across the 132 duplicates. It affects whether the match tells you which physical thickness is on the way, which is a separate question from whether the electrical spec is right.”,”visible”:true},{“id”:”faq-question-06″,”title”:”What is the Symbol column, and is it part of the orderable part number?”,”content”:”Our reading is that it is a thickness or dimensional-variant code Walsin tracks internally, since it is the one column that always differs between rows sharing a Part Number string. We have not confirmed whether the true orderable code appends the Symbol letter to the string, and we are flagging that for Walsin rather than asserting it.”,”visible”:true},{“id”:”faq-question-07″,”title”:”What should I do if the part number I am sourcing is one of the 132?”,”content”:”Ask us for the thickness and the Symbol letter before you order. Send the part number through the free cross-reference tool or directly to us, and we will return the specific row rather than letting a spreadsheet lookup pick one of two or three candidates for you.”,”visible”:true}],”listStyle”:””,”titleWrapper”:”h3″,”titleCssClasses”:””,”contentCssClasses”:””,”sizeSlug”:””} –>

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