The Walsin MLCC reflow-only mark is written four different ways across 12 approval sheets, and none of it reaches the parametric export. We counted 85 hash marks in 9 sheets, joined them to the export, and found 2,642 of 4,095 high-voltage rows sit in a marked cell. The export column called “Remark” means something else.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds 28 datasheets from Walsin Technology (Walsin), 451 pages. This post is written from the first 14 PDFs alphabetically, 252 pages, of which 12 are series approval sheets, and from the MLCC parametric export of 24,026 rows. We opened every external-dimensions table, counted the soldering marks cell by cell, and joined them to the export on case size and thickness symbol. Every part number is real. The question is the one a process engineer asks before choosing a line: can this part go through the wave, and where in Walsin’s data does it say so?
How many ways do Walsin’s 12 MLCC approval sheets mark a reflow-only part?
Four. We read the external-dimensions table of each series sheet and recorded where soldering guidance sits. Nine sheets (04 to 12) carry a column headed “Remark” with a hash mark per reflow-only thickness cell, 85 marks in all; one sheet carries a “Soldering Method” column of R or R/W letters; two carry a footnote and no marked cell at all. The 65-page catalogue and the application guide are not approval sheets and are left out.
| Sheet file | How soldering is shown | Marks counted | A real part in the table | Match / mismatch against the export |
|---|---|---|---|---|
01_General_Purpose |
“Soldering Method” column, letter R or R/W per cell | 38 cells, 10 R/W, 28 R | 0201B102K160 |
Mismatch — the export has no method field |
02_Ultra_Small_01005 |
footnote “* Reflow soldering only.” | 0 cells marked | 01R5N0R8B160 |
Mismatch — one asterisk footnote, no column |
03_Large_Size_1825_2220_2225 |
footnote “# Reflow soldering only is recommended.” | 0 cells marked | 1825B224K631 |
Mismatch — a hash footnote and no reflow mark in the table |
04_Middle_and_High_Voltage |
“Remark” column | 20 | 0805B103K251 |
Mismatch — export “Remark” means customized product |
05_Surface_Coating_Type |
“Remark” column | 15 | termination code M, not a series | Mismatch |
06_Microwave_RF |
“Remark” column | 5 | RF03N0R1A250 |
Mismatch |
07_Microwave_High_Reliability_RH |
“Remark” column | 2 | none, no export rows | Mismatch |
08_Microwave_Narrow_Tolerance_UF |
“Remark” column | 2 | UF03N0R1A101 |
Mismatch |
09_Microwave_Automotive_RT |
“Remark” column | 2 | none, no export rows | Mismatch |
10_High_Q_Low_ESR_HH |
“Remark” column | 3 | HH15N0R2A500 |
Mismatch |
11_Automotive_MT |
“Remark” column | 13 | MT15N0R5C500 |
Mismatch |
12_Soft_Term_Automotive_ST |
“Remark” column | 23 | ST18B473K500 |
Mismatch |
The same three sizes make the point. 1825, 2220 and 2225 are marked in sheets 05 and 12, one hash each, and carry no mark in sheet 03, the sheet written for exactly those sizes. We have not seen this counted anywhere: 12 sheets, 4 notations, and the dedicated large-size sheet is the one with a reflow-only footnote and not a single marked cell.
What does “Remark” mean in a Walsin datasheet and in the export?
Two unrelated things. In the nine approval sheets the “Remark” column holds a hash mark meaning “reflow soldering only is recommended”. In the MLCC export the “Remark” column holds a customized-product note on 432 of 24,026 rows, in seven spellings, and three rows hold a bare asterisk. We searched all 384,416 cells (24,026 rows by 16 columns) for a hash and for the words “reflow”, “method” and “solder” in any case, and found none.
The 432 customized-product rows are covered in our post on the customized-part flag. The three asterisk rows are the safety series part S242N221J502 and two rows of S242N390J502. A script that reads the export column named “Remark” and expects soldering guidance gets customization notes. A person who reads the datasheet’s “Remark” and expects customization finds a hash. The shared word is the trap.
How many high-voltage export rows sit in a reflow-only cell?
2,642 of 4,095 by a literal join, 64.5 percent. We read the 25 thickness cells of the middle-to-high-voltage sheet, 20 of them marked, and joined each (case size, thickness symbol) pair to the export’s Size and Symbol columns. The join holds because the export’s thickness values agree with the sheet cell by cell.
| Case size | Export rows | Rows in a marked cell | Share | Match / mismatch against a case-size-only wave rule |
|---|---|---|---|---|
| 0402 | 44 | 44 | 100% | Match — 0402 is outside the guide’s wave list, and the sheet agrees |
| 0603 | 317 | 0 | 0% | Match — all unmarked, and the guide lists 0603 |
| 0805 | 927 | 327 | 35% | Mismatch — same case size, split by thickness |
| 1206 | 1,285 | 751 | 58% | Mismatch — same case size, split by thickness |
| 1210 | 615 | 615 | 100% | Match — the guide excludes 1210 and above |
| 1808 | 336 | 336 | 100% | Match |
| 1812 | 570 | 569 | 99.8% | Match — one row carries a lower-case symbol and falls out of a literal join |
The five unmarked cells are 0603 S and X, 0805 A and B, and 1206 B, every one 0.80 mm or thinner. Every cell at 0.95 mm or thicker is marked, and so is the 0402 cell at 0.50 mm. Examples: 0805B101K251 sits in an unmarked 0805 B cell and 0805B103K251 in a marked 0805 D cell. The table rows sum to 4,094; the 4,095th is the tab-jammed 1808B102M252, which falls out of a literal join along with the lower-case symbol row. Read as intended, the count is 2,644.
Does the General Purpose method column agree with the application guide?
Not on one cell. The application guide (page 8 of 12, January 2022) says wave soldering is recommended only for 0603, 0805 and 1206, with thickness under 1 mm. In the General Purpose sheet 10 of 38 thickness cells are R/W. Nine are under 1 mm. The tenth, 1206 symbol G at 1.60 mm, is R/W and breaches the guide’s limit. The sentence can be read as applying the 1 mm limit to 1206 only or to all three sizes; under either reading 1.60 mm is outside it.
We placed each R and W token against its thickness symbol by page coordinates, so the merged cell beside 0603 B and X is read as covering both. The join then gives the row counts.
| Cell | Thickness | Sheet 01 method | Export rows | Match / mismatch against the guide’s under-1-mm rule |
|---|---|---|---|---|
| 0603 S and X | 0.80 mm | R/W | 1,937 | Match |
| 0805 A, B and T | 0.60 to 0.85 mm | R/W | 1,265 | Match |
| 1206 B | 0.80 mm | R/W | 828 | Match |
| 1206 G | 1.60 mm | R/W | 24 | Mismatch — wave offered above the limit, e.g. 1206B106M6R3 |
| 1206 C | 0.95 mm | R | 57 | Sheet stricter than the guide, not a conflict |
| 1206 J, D, P | 1.15 to 1.60 mm | R | 369 | Match — reflow only and over the limit |
In total 4,054 of 8,467 General Purpose rows, 47.9 percent, sit in an R/W cell; 4,408 sit in R-only cells and 5 sit in cells the sheet does not list (three 0306 rows, two with a lower-case symbol). The export carries none of it. For the guide-based count of parts that fail the thickness limit across the whole export, see which Walsin MLCC can be wave soldered. That post reads the guide alone; this one adds that the sheet and the guide disagree on 24 rows.
Does “#1” mean the same thing twice on one sheet?
No. Three sheets use the label “#1” for two unrelated footnotes: 01, 04 and 11. We read both sections of each. In sheet 04 the first “#1” attaches a dimension tolerance to named 1210B parts and the second says that NP0 at 0.1 pF and 5 to 10 pF needs a check with sales before tolerance A is offered. Sheet 02 also reuses one glyph: its asterisk means “reflow only” in the dimensions table and “measured at 30 to 70 percent relative humidity” in the electrical table.
“#2” is five different footnotes in the five sheets that have one: 01, 02, 04, 11 and 12. In 11 it names one 1210 part code at 200 V and 250 V; in 12 it names a different 1210 code at 1250 V. A parser keyed on the glyph and the digit would merge unrelated rules.
What should a process filter use instead?
The sheet, the case size and the thickness symbol, read from the datasheet, with the export used only for the part list, because 0 of 384,416 export cells hold the mark. Three rules follow from the counts.
- Never infer reflow-only from the export. 0 of 384,416 cells hold it.
- Read the mark by sheet. Hash marks are in 9 sheets, letters in 1, and a bare footnote in 2.
- Treat the guide and the sheet as two sources. They disagree on 24 General Purpose rows.
We hold 28 Walsin datasheets, 451 pages, and send them on request. We hold none for thin film, inductor, varistor, disc capacitor, RF or antenna lines. Paste your incumbent into our free cross-reference tool and we will show which sheet governs the Walsin part it returns; the part-number structure is in how to read a Walsin MLCC part number. What is in Hong Kong is on ready stock, 1,125 part numbers as at 23 September 2026, and the range sits on the MLCC page.
The short version
Walsin marks reflow-only parts four ways: an R or R/W letter column in the General Purpose sheet, an asterisk footnote in the 01005 sheet, a hash footnote with no marked cell in the large-size sheet, and a hash in a “Remark” column in nine sheets, 85 marks in all. The export holds none of it; its “Remark” column means customized product. The middle-to-high-voltage sheet places 2,642 of 4,095 rows in marked cells. The General Purpose sheet offers wave soldering on 24 rows at 1.60 mm that the application guide would exclude. The label “#1” means two things on one sheet in three sheets. Qualification stays with you.
Send us the part numbers on your wave line and we will return the sheet cell each one sits in. And a question back: when your solder-process filter read the export, which column did it trust?
Frequently asked questions
How does Walsin mark an MLCC as reflow soldering only?
Four ways across the 12 series approval sheets we opened. Nine sheets use a hash mark in a Remark column, 85 marks in all. The General Purpose sheet uses a soldering method column of R and R/W letters. The 01005 sheet uses an asterisk footnote, and the large-size sheet prints a hash footnote with no marked cell.
Does the Walsin MLCC export say which parts are reflow only?
No. We searched all 384,416 cells of the 24,026-row export for a hash, reflow, method and solder and found none. The export column named Remark holds a customized-product note on 432 rows and a bare asterisk on three. The soldering guidance exists only in the datasheets.
Which Walsin MLCC sizes are marked reflow only in the high-voltage sheet?
In the middle-to-high-voltage sheet 20 of 25 thickness cells carry the mark. Every 1210, 1808 and 1812 cell and the 0402 cell are marked, as is every cell at 0.95 millimetre or thicker. A literal join places 2,642 of 4,095 export rows, 64.5 percent, in a marked cell.
Does the Walsin General Purpose sheet allow wave soldering above 1 mm?
On one cell it does. The sheet marks 10 of 38 thickness cells R/W, and one of them, 1206 symbol G at 1.60 millimetres, exceeds the 1 millimetre limit in the application guide. That cell holds 24 export rows. The guide and the sheet disagree there, and Walsin should be asked which governs.
Is the hash footnote a ban on wave soldering?
No. The footnote in the sheets reads reflow soldering only is recommended. It is guidance, not a prohibition, and we read printed marks only. Whether a given part may pass through a wave is a question for Walsin applications engineers and for your own process qualification.
Does Venatech hold every Walsin datasheet?
No. We hold 28 Walsin datasheets, 451 pages, covering 26 MLCC and 2 chip resistor documents. We hold none for thin film, inductor, varistor, disc capacitor, RF or antenna lines. This post uses 14 of the 28 files, 252 pages, and covers MLCC only.