A duplicate MLCC part number in Walsin’s export is usually two thicknesses of one part. We parsed all 24,026 rows: 23,601 part numbers are distinct, 399 appear more than once, 425 rows are surplus, and 339 of the 399 repeat with a different nominal height. None repeats across two series.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the MLCC parametric export of Walsin Technology (Walsin) as 22 per-series files and a combined file, 00_ALL_MLCC_parts_combined.xlsx. This post is written from the Part Number, Series and T columns of all of them, compared row by row. An earlier post counted repeats inside the General Purpose series alone; this one covers every series. Every part number below is real. The question is the one every bill-of-materials lookup depends on: is a part number a unique key?
How many MLCC part numbers repeat in the full Walsin export?
399 of 23,601. We counted distinct values in the Part Number column of the combined file. The file has 24,026 rows and 23,601 distinct part numbers, so 425 rows are surplus. 399 part numbers account for 824 rows: 375 appear twice, 23 three times and one five times. That is 1.7 percent of the distinct part numbers.
The earlier count in Walsin MLCC duplicate part number: 132 of 8,330 looked only at the 8,467 General Purpose rows. Those 132 are one third of the whole-file total.
| Measure | Count | Match / mismatch against “a part number is a unique key” |
|---|---|---|
| Rows in the combined export | 24,026 | reference |
| Distinct part numbers | 23,601 | Mismatch — 425 fewer than rows |
| Part numbers on more than one row | 399 | Mismatch — 1.7% of distinct part numbers |
| Rows those 399 occupy | 824 | Mismatch — 3.4% of all rows |
| Part numbers repeating across two series | 0 | Match — every repeat is inside one series |
We have not seen this counted anywhere across all sixteen series that carry rows.
Do the per-series files and the combined file disagree?
No. We opened all 22 per-series files. Sixteen hold parts and six hold only a note, two rows with no part number, which is covered in six MLCC series return zero parts. The sixteen files hold 24,026 rows between them, the same as the combined file, and every part number in one is in the other: zero are missing in either direction.
So combining the files adds no repeats and removes none. Every repeat sits inside a single per-series file, and a reader who works from one series file meets the same duplicates the combined file shows.
What differs between the rows of a repeated part number?
Almost always the height. We compared the T thickness text for every repeated part number, reading nominal and upper tolerance. Of 399, 339 carry two or more different nominal heights, 37 share a nominal but differ in upper tolerance, 9 have a blank height on one row beside a value on another, and 14 repeat the height identically. Capacitance, rated voltage and size agree on all but a handful.
| Part number | Series | Size | Capacitance | Rated voltage | Heights across the repeated rows | Match / mismatch between the rows |
|---|---|---|---|---|---|---|
0805B101K102 |
Middle to High Voltage | 0805 | 100 pF | 1,000 Vdc | 0.80 ± 0.10 and 1.25 ± 0.10 mm | Match on size, capacitance and voltage. Mismatch on nominal height, by 0.45 mm |
0805B102K500 |
General Purpose | 0805 | 1,000 pF | 50 Vdc | 0.60, 0.80 and 1.25 mm (three rows) | Mismatch — three nominal heights on one part number |
1210B474K101 |
General Purpose | 1210 | 470 nF | 100 Vdc | 1.25 ± 0.10 and 2.50 ± 0.30 mm | Mismatch — a 1.25 mm gap, the widest we found |
MT21B224K500 |
Automotive MT | 0805 | 220 nF | 50 Vdc | 1.25 ± 0.10 and 1.25 ± 0.20 mm | Match on nominal. Mismatch on maximum, 1.35 against 1.45 mm |
0603B102K500 |
General Purpose | 0603 | 1,000 pF | 50 Vdc | 0.80 ± 0.07 mm and a blank | Mismatch — one row has no height |
0603X225K160 |
General Purpose | 0603 | 2,200 nF | 16 Vdc | 0.80 + 0.15 / − 0.10 mm on both | Match on height |
The most common gap is 0.45 mm, 157 of the 339 groups: a 0.80 mm row and a 1.25 mm row of one part number (six of the 157 also carry a 0.95 mm row). In 165 of the 339, the lower row clears a 1.00 mm limit and the higher row does not. For how nominal and tolerance combine into a maximum, see MLCC height tolerance.
Which series carry the repeats, and which do not?
Nine series carry them, and seven carry none. The Middle to High Voltage series holds 208 of the 399 repeated part numbers, 52.1 percent, on 432 rows. General Purpose holds 132, soft termination SH 32, Big Sizes 10 and the S2 safety series 7. Automotive MT, MG and High Q each hold 3, and the Low Profile TT series holds 1.
| Series | Repeated part numbers | Rows they occupy | Share of the series’ distinct part numbers | Match / mismatch against “no repeats” |
|---|---|---|---|---|
| Middle to High Voltage | 208 | 432 | 5.4% | Mismatch |
| General Purpose | 132 | 269 | 1.6% | Mismatch |
| Soft termination SH | 32 | 68 | 2.2% | Mismatch |
| Big Sizes | 10 | 20 | 2.0% | Mismatch |
| Safety S2 | 7 | 15 | 4.2% | Mismatch |
| Automotive MT, MG, High Q HH | 3 each | 6 each | 0.1% to 0.4% | Mismatch |
| Low Profile TT | 1 | 2 | 1.8% | Mismatch |
| Microwave RF, Ultra Microwave UF, 01R5, HT, ST, SG, FT | 0 | 0 | 0 | Match |
The Microwave and Ultra-small lines, which carry 4,217 rows between them, repeat nothing. The repeats concentrate where a part number is offered in more than one thickness.
What does a lookup on part number return?
Whichever row comes first. We tested the order of the 339 groups that differ in nominal height. In 159 of 339, 46.9 percent, the first row in the combined file is the thickest; in the rest it is not. A lookup that keeps the first row returns the thick part about as often as the thin one.
We also looked at the customized flag. In 271 of the 339 groups the thicker row carries the Remark text that marks a customized product, the flag counted in Walsin MLCC customized part: 432 rows flagged. A part number is not a safe key; part number plus thickness is.
How should a repeated MLCC part number be handled?
Keep every row and add the thickness to the key. Do not drop duplicates on part number: it discards 425 rows and, in 339 groups, a different height. Our free cross-reference tool lists thickness and tolerance as fields to double check and states differences from your original, so a repeated part number shows both rows. It accepts up to 500 part numbers or an Excel or CSV file.
We hold 28 Walsin datasheets, 451 pages, covering all 16 MLCC series with export rows; ask for the one covering your part number and it will be in your inbox. Confirm against both datasheets and qualify in your own circuit. Hong Kong stock is on the ready stock page, a dated snapshot of 1,125 part numbers as at 23 September 2026 and not a live feed. The capacitor range is on the MLCC page.
The short version
We parsed all 24,026 rows. 23,601 part numbers are distinct; 399 repeat on 824 rows. 339 repeat with a different nominal height, 37 with a different tolerance, 9 with a blank, 14 identically. Nine series carry repeats and none repeats across series. Middle to High Voltage holds 208 of the 399. The first row is the thickest in 159 of 339. Key on part number plus thickness.
Send us the part numbers on your bill of materials and we will tell you which ones occupy more than one row, and at what height. And a question back: when your lookup returned one thickness for a part number, how did it choose?
Frequently asked questions
How many duplicate part numbers are in the Walsin MLCC export?
399 part numbers appear on more than one row, occupying 824 of the 24,026 rows. 375 appear twice, 23 three times and one five times. The file holds 23,601 distinct part numbers, so 425 rows are surplus. None repeats across two series.
Do duplicate Walsin MLCC rows have the same specification?
Mostly the same capacitance, size and rated voltage, but not the same height. 339 of the 399 repeated part numbers carry two or more different nominal heights, 37 differ in upper tolerance, 9 have a blank height on one row, and 14 repeat the height identically.
Which Walsin MLCC series has the most duplicate part numbers?
Middle to High Voltage, with 208 of the 399 repeated part numbers on 432 rows, 5.4 percent of its distinct part numbers. General Purpose holds 132, soft termination SH 32, Big Sizes 10 and the S2 safety series 7.
Does the combined MLCC file differ from the per-series files?
No. The sixteen per-series files that hold parts total 24,026 rows, equal to the combined file, and no part number is missing in either direction. Six further files hold only a two-row note and no parts.
Can I use the MLCC part number as a unique key?
Not on its own. 399 part numbers repeat, and in 339 of them the repeated rows differ in nominal height, by up to 1.25 mm. Use part number plus thickness, and keep every row.
Which duplicate row does a spreadsheet lookup return?
The first one it meets. In 159 of the 339 groups that differ in nominal height, 46.9 percent, the first row in the combined file is the thickest, so the answer depends on row order. Check the thickness against your height limit before accepting it.