A Walsin datasheet revision date is a month and a year, and nothing more on 25 of the 27 stamped sheets. We read the footer on all 451 pages. Only the two resistor sheets print a version number, and 17 of 24 series sheets carry an ID that is not their published file name.
If you file a datasheet against a part number in an approved vendor list, the footer is the only revision control you are given. Venatech Limited, an authorised Walsin distributor in Hong Kong, holds 28 Walsin Technology (Walsin) datasheets, 451 pages. We opened every one, extracted the text of every page and read one line: the footer. We checked it against the file name Walsin publishes each sheet under. Every part number below is real and checked against our master set. We will not tell you two sheets agree because they look alike. We will show you where they differ.
How many of Walsin’s 28 datasheets carry a revision date on every page?
27 of 28. We counted the footer on each page: 386 of the 451 pages carry a date stamp, and the 65-page 00_MLCC_Full_Catalogue.pdf carries none that our text extraction found. On each of the 27 stamped sheets the footer is on every page, and the “Page N of M” total equals the real page count on every one. So the date is a property of the whole sheet, never of one page.
| What the footer shows | Sheets, of 28 | Pages | Match / mismatch against a revision-controlled document |
|---|---|---|---|
| A date on every page | 27 | 386 | Match on date, mismatch on version (next section) |
| No footer of any kind | 1 — the MLCC catalogue | 65 | Mismatch — nothing to file the revision against |
| A date inside 2026 | 24 — every MLCC series sheet | 354 of 386 stamped pages | Match — all 24 are dated January to September 2026 |
| A date before 2026 | 3 — application guide, MR, WR | 32 | Mismatch — January 2022, March 2024, September 2016 |
We have not seen this counted anywhere: a distributor sends you a datasheet, and the only thing that dates it is a footer that exists on 27 of the 28 documents we hold.
Does a Walsin datasheet carry a version number as well as a date?
On two sheets only. ASC_WR_V24 and ASC_MR_V13, the two resistor approval sheets, carry a version token. The other 25 stamped sheets carry a month and a year and no version, no revision letter and no change history. If Walsin reissues an MLCC series sheet in the same month, the footer cannot tell you which copy you hold.
| Document | Series | Footer as printed | Version token | Example part | Your copy’s footer | Match / mismatch |
|---|---|---|---|---|---|---|
Walsin_WR_General_Purpose_Chip_Resistor.pdf |
WR | ASC_WR_V24 SEP 2016 |
V24 | WR06X1002FTL |
Date and version both printed | |
Walsin_MR_Automotive_Thick_Film_Chip_Resistor.pdf |
MR | ASC_MR_V13 Mar - 2024 |
V13 | MR06X1002FTL |
Date and version both printed | |
01_General_Purpose.pdf |
General Purpose | ASC_General Purpose Series Sep. 2026 |
none | 0603B104K500 |
Mismatch — date only | |
21_Low_Profile_TT.pdf |
Low Profile TT | ASC_ Low Profile_(TT)_009S_AS Apr. 2026 |
none; 009S_AS is unexplained |
TT15X105K6R3 |
Mismatch — a suffix that is not a version | |
10_High_Q_Low_ESR_HH.pdf |
HH | WTC_MLCC_HQ_Low_ESR_HH Sep. 2026 |
none | HH03N0R1B500 |
Mismatch — date only |
The TT footer is the one to watch. It ends _009S_AS, which looks like a revision code and is not defined anywhere in the sheet’s nine pages. Treat it as part of the name, not as a version. The 2026 MLCC series sheets are available from Walsin’s public site, for example the General Purpose sheet.
Does the document ID in the footer match the file name Walsin publishes?
Seven times out of 24. 17 of the 24 MLCC series sheets are stamped with a document ID that differs from the file name Walsin publishes them under, and 13 of the 24 footer IDs contain a space. Every published file name begins WTC_MLCC_. Seven footers say the same; 17 begin ASC, 15 with an underscore and two with a space.
| Series | Example part | Footer document ID | Published file name (without .pdf) |
Date as printed | Match / mismatch |
|---|---|---|---|---|---|
| Large size 1825 to 2225 | 1825B102K302 |
WTC_MLCC_1825_2220_2225 |
WTC_MLCC_1825_2220_2225 |
Apr. 2026 | Match |
| High Q Low ESR HH | HH03N0R1B500 |
WTC_MLCC_HQ_Low_ESR_HH |
WTC_MLCC_HQ_Low_ESR_HH |
Sep. 2026 | Match |
| Soft termination SG | SG18B102K500 |
WTC_MLCC_Soft_term_SG |
WTC_MLCC_Soft_term_SG |
Sep. 2026 | Match |
| Soft termination SH | SH15B102J500 |
ASC_Soft termination_(SH) |
WTC_MLCC_Soft_term_SH |
Sep. 2026 | Mismatch — prefix, spelling and a space |
| Automotive MT | MT15N101K500 |
ASC_ Automotive Cap_(MT) |
WTC_MLCC_Automotive_MT |
Aug. 2026 | Mismatch — prefix, wording and a stray space |
| Ultra-small 01R5 | 01R5B101K100 |
ASC_Ultra Small_(01R5) |
WTC_MLCC_Ultra_Small_01R5 |
May.2026 | Mismatch — prefix and brackets |
| Safety X1/Y2 S2 | none quoted | ASC Safety Certified X1/Y2_(S2) |
WTC_MLCC_Safety_Certified_S2 |
Apr.2026 | Mismatch — a slash in a document ID |
The consequence is practical. A footer such as ASC Safety Certified X1/Y2_(S2) will not paste into a file name, a search box or a document-control register without editing, and the edited form will not match the name on the download. Record the footer text exactly as printed and the file name separately.
Are the dates written the same way on every Walsin sheet?
No. The 27 stamped sheets use 11 different date strings for 8 different dates. We grouped every footer. Three months, April, September and May 2026, are each written two ways on different sheets: with a space after the full stop and without one.
| Date | Sheets | How it is written | Match / mismatch against one spelling per date |
|---|---|---|---|
| April 2026 | 9 | Apr. 2026 on 6, Apr.2026 on 3 |
Mismatch — two spellings |
| September 2026 | 8 | Sep. 2026 on 5, Sep.2026 on 3 |
Mismatch — two spellings |
| May 2026 | 4 | May.2026 on 3, May. 2026 on 1 |
Mismatch — two spellings |
| August 2026 | 2 | Aug. 2026 on 2 |
Match |
| January 2026 | 1 | Jan. 2026 on 1 |
Match |
| January 2022 | 1 | Jan. 2022, the MLCC application guide |
Match |
| March 2024 | 1 | Mar - 2024, MR resistor |
One-off format with a hyphen |
| September 2016 | 1 | SEP 2016, WR resistor |
One-off format in capitals |
A text filter for Sep. 2026 finds 5 of the 8 September 2026 sheets. A sort on the string puts SEP 2016 among the capitals and Mar - 2024 after Jan. 2026. Parse the month and year; never compare the string.
How old are the two resistor datasheets next to the MLCC series sheets?
Nine years and four months, and twenty-two months. The WR sheet is dated September 2016, which is 9 years 4 months before the oldest MLCC series sheet, January 2026. The MR sheet is dated March 2024, 22 months before it. Both are older than every one of the 24 MLCC series sheets, and both are the only documents we hold for any resistor.
That is why a resistor reliability claim, a marking claim or a rated-current claim from us comes with the sheet name and its stamp, not a summary. The WR specification history is covered in our reading of ASC_WR_V24 and the two series are set side by side in WR and MR compared field by field. We hold no datasheet for thin film, inductor, varistor, disc capacitor, RF or antenna parts at all, so on those lines there is no footer for us to read.
What should you ask for before you file a datasheet against a part number?
Ask for the sheet that covers your exact part number, and record its footer exactly as printed. We hold 28 datasheets, 451 pages, and we send the one covering your part number on request. Three habits remove most of the ambiguity this post counted.
- Record the footer verbatim, plus the download file name. 17 of 24 series sheets differ between the two.
- Parse the date, never compare it as text. 8 dates are written 11 ways.
- For the two resistor lines, record the version as well. V24 and V13 are the only version tokens on file.
We will not tell you a sheet is current. We will tell you what the sheet in our hands says it is, and Walsin confirms the rest. What is in Hong Kong is on ready stock — 1,125 part numbers as at 23 September 2026, a dated snapshot and not a live feed. To cross a part to Walsin first, use the free cross-reference tool. The capacitor range sits on the MLCC page.
The short version
We read the footer on all 451 pages. 27 of 28 sheets are stamped on every page, 386 pages in all, and the 65-page catalogue carries none. 25 of the 27 carry a month and a year and no version number; only ASC_WR_V24 and ASC_MR_V13 carry one. 17 of 24 MLCC series footers differ from the published file name, 13 contain a space. 8 dates are written 11 ways. All 24 series sheets are dated 2026, January to September; the resistor sheets are dated 2016 and 2024. Qualification stays with you: confirm against both datasheets and qualify in your own circuit.
Send us the part number and the footer text on the sheet you hold, and we will tell you whether it is the sheet we hold. And a question back: when your last audit asked for the datasheet revision, what did you write in the box?
Frequently asked questions
Do Walsin datasheets have a revision number?
Only the two resistor sheets do. The WR sheet is stamped ASC_WR_V24 and the MR sheet ASC_MR_V13. The other 25 stamped sheets, all MLCC, carry a month and a year and no revision number, letter or change history, so two issues in the same month cannot be told apart from the footer.
How many Walsin datasheets carry a date?
27 of the 28 we hold, with a footer on every one of 386 pages. The 65-page MLCC catalogue is the exception: our text extraction found no footer on any of its pages. All 24 MLCC series sheets are dated between January and September 2026.
Does the footer ID match the Walsin file name?
On 7 of 24 MLCC series sheets it does. On the other 17 the footer begins ASC while the published file name begins WTC_MLCC, and 13 of the 24 footer IDs contain a space. Record both the footer and the file name when you file the sheet.
Why do the same month and year look different on two sheets?
Because the footer is typed, not generated. April 2026 is written Apr. 2026 on six sheets and Apr.2026 on three. September 2026 and May 2026 split the same way. Across the 27 stamped sheets there are 11 date strings for 8 dates. Parse the month and year rather than comparing the text.
How old are the Walsin resistor datasheets you hold?
The WR general purpose sheet is dated September 2016 and the MR automotive sheet March 2024. They are the only resistor datasheets we hold. We hold none for thin film, so a thin film specification must be confirmed against Walsin’s own site.
Can you send the datasheet for my part number?
Yes. We hold 28 Walsin datasheets, 451 pages, and send the one covering your part number on request. For inductor, varistor, disc capacitor, RF, antenna and thin film we hold none. We will tell you that plainly rather than send a neighbouring sheet.