The chip resistor TCR datasheet and the export disagree on 2,700 of 19,640 Walsin WR rows, 13.7 percent, and on none of 13,552 MR rows. All 2,700 sit in two series. 1,182 of them are looser than even the newer MR sheet allows, and every one carries “100ppm” in its series name.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the chip resistor parametric exports published by Walsin Technology (Walsin) and two chip resistor approval sheets. This post is written from the general purpose files, tested row by row against the TCR table each sheet prints. Every part number below is real and every count is of part numbers, not pieces. The question is the one a qualification engineer asks first: if the export says a part is 100 ppm, is that what the datasheet says?
Does Walsin’s TCR column agree with its own datasheets?
For MR, completely. For WR, on 86.3 percent. We parsed the TCR string on every non-jumper WR row at 1206, 0805, 0603 and 0402 (19,640 rows) and every MR row at 1210, 1206, 0805, 0603 and 0402 (13,552 rows), then compared each with the limit its own sheet prints for that resistance. MR departs on zero rows. WR departs on 2,700, and the 2,700 are not spread: they sit in two of the four WR series.
| Series | Prefix | Rows tested | Rows with a looser TCR than the sheet | Share | Match / mismatch against the sheet |
|---|---|---|---|---|---|
| General Purpose (Automotive) | MR | 9,680 | 0 | 0% | Match |
| General Purpose LF 100ppm (Automotive) | MR | 3,872 | 0 | 0% | Match |
| General Purpose | WR | 4,152 | 0 | 0% | Match (280 rows are tighter, see below) |
| General Purpose (Automotive) | WR | 3,872 | 0 | 0% | Match |
| General Purpose Anti-Sulfuration (Automotive) | WR | 7,744 | 1,104 | 14.3% | Mismatch on 1,104 |
| General Purpose LF 100ppm | WR | 3,872 | 1,596 | 41.2% | Mismatch on 1,596 |
| All | 33,192 | 2,700 | 8.1% | MR 0 of 13,552; WR 2,700 of 19,640 |
We have not seen this counted anywhere: the export tested against both resistor sheets at full population, band by band. The export holds only five distinct TCR strings at these sizes: ≦±100 on 24,360 rows, -200～+400 on 4,200, ≦±200 on 3,932, -300～+500 on 560 and ≦±300 on 140. A sheet that prints three limits and a column that prints five strings can only agree by design, and MR does. For the 280 WR rows that publish a tighter TCR than the sheet requires, see the flagged note below.
What do the WR and MR sheets print for TCR, and where do they differ?
WR prints two limits and MR prints three. The sheets are not the same age: Walsin_WR_General_Purpose_Chip_Resistor.pdf is ASC_WR_V24, September 2016, and Walsin_MR_Automotive_Thick_Film_Chip_Resistor.pdf is ASC_MR_V13, March 2024. We read page 3 of both. WR states 100 ppm per degree Celsius for every resistance above 10 ohm up to 10 megohm; MR states 100 up to 1 megohm and 200 above it. Below 10 ohm both state minus 200 to plus 400.
| Resistance band | WR sheet (2016) | MR sheet (2024) | Match / mismatch between the two sheets |
|---|---|---|---|
| 10 ohm or less | -200 to +400 | -200 to +400 | Match |
| Above 10 ohm to 1 megohm | 100 | 100 | Match |
| Above 1 megohm to 10 megohm | 100 | 200 | Mismatch — MR twice as loose |
So the two sheets disagree on one band, and the WR sheet is the older of the two. A WR row at 1.5 megohm that publishes ≦±200 departs from the WR sheet and agrees with the MR sheet. Whether the WR sheet is out of date for that band, or the row is wrong, is a question for Walsin.
Which resistance bands carry the 2,700 departing WR rows?
All three, unevenly. We grouped the 2,700 by resistance band and by the string the export prints: 1,656 are above 1 megohm, 484 are between 10 ohm and 1 megohm, and 560 are at 10 ohm or below. The 1,656 include 1,104 in the anti-sulfuration series, all at ≦±200.
| Part number | Series | Size | Resistance | Export TCR | WR sheet limit | Your incumbent | Match / mismatch |
|---|---|---|---|---|---|---|---|
WR06X1004FTL |
General Purpose | 0603 | 1 megohm | ≦±100 |
100 | Match | |
WR06X1004FTR |
LF 100ppm | 0603 | 1 megohm | ≦±200 |
100 | Mismatch — 2x the sheet | |
WR06W1024FTL |
General Purpose | 0603 | 1.02 megohm | ≦±100 |
100 | Match | |
WR06W1024FTLV |
Anti-Sulfuration (Automotive) | 0603 | 1.02 megohm | ≦±200 |
100 | Mismatch — 2x the sheet | |
WR04W1024FTR |
LF 100ppm | 0402 | 1.02 megohm | ≦±300 |
100 | Mismatch — 3x the sheet | |
WR06W1R00FTL |
General Purpose | 0603 | 1 ohm | -200～+400 |
-200 to +400 | Match | |
WR06W1R00FTR |
LF 100ppm | 0603 | 1 ohm | -300～+500 |
-200 to +400 | Mismatch — 100 ppm wider at each end |
The departures repeat at all four sizes. 675 sit at each of 0402, 0603, 0805 and 1206. The termination letter splits them too: 920 end FTR, 676 end JTR, 552 end TLV and 552 end TLZ. The R in FTR is not defined in the WR sheet, a gap we covered in stock against datasheet.
How many WR rows still depart once the 2024 banding is applied?
1,182 of 3,872 in the LF 100ppm series, and none anywhere else. We re-ran the test with the MR sheet’s three bands applied to WR. The 1,104 anti-sulfuration rows at ≦±200 above 1 megohm are inside the 200 limit and drop out. So do 414 LF rows at ≦±200 above 1 megohm. What remains is 138 at ≦±300 above 1 megohm, 484 between 10 ohm and 1 megohm, and 560 at 10 ohm or below.
| Reading of the sheets | Rows departing | Where they sit | Match / mismatch |
|---|---|---|---|
| WR sheet as printed (2016) | 2,700 of 19,640 | Anti-sulfuration 1,104; LF 100ppm 1,596 | Mismatch |
| MR banding applied to WR (2024) | 1,182 of 19,640 | LF 100ppm only, 1,182 of 3,872 (30.5%) | Mismatch |
| Either reading | 0 | General Purpose and General Purpose (Automotive) | Match on 8,024 rows |
We have not seen this counted anywhere: 1,182 rows that depart from every TCR limit in the two resistor sheets Venatech holds, and every one of them is in a series named for 100 ppm.
Does a 100ppm in the series name guarantee 100 ppm?
No. In the WR LF 100ppm series at the four sheet sizes, 2,276 of 3,872 rows publish ≦±100, which is 58.8 percent. We matched each of the 3,872 LF rows to the plain General Purpose row at the same size, resistance and tolerance. All 3,872 have a twin, and 1,596 of them (41.2 percent) publish a looser TCR than the twin. The split is 896 at ≦±200, 140 at ≦±300 and 560 at -300～+500 against the twin’s -200～+400.
The plain series is the tighter one wherever the two differ. That is the opposite of what the LF 100ppm name suggests. We did not find the LF letters defined in either sheet. A series name is a family label, not a TCR guarantee, and the same pattern in the high power line is in what resistor TCR actually buys you.
What should a TCR filter check before it relies on the column?
Three things, each measured above. We counted the column’s strings before we used it, and you should do the same for yours. The five strings use ≦ (U+2266) and a full-width tilde ～ (U+FF5E), so they cannot be sorted or cast as numbers.
- Test the band, not the series name. TCR depends on resistance. Check the string at your resistance, not the family label.
- Read the sheet that governs your prefix. WR and MR disagree on the 1 to 10 megohm band, by a factor of two.
- Cross the whole list in one pass on the free cross-reference tool. Paste up to 500 part numbers or drop an Excel or CSV. It is matched against Walsin’s published catalogue and states every difference from your original. Then check ready stock, a dated snapshot of 1,125 part numbers as at 23 September 2026, not a live feed.
The WR and MR dimension and test comparison is in WR and MR series compared, field by field. The range sits on the Walsin chip resistor page. Confirm against both datasheets and qualify in your own circuit. We hold 28 Walsin datasheets, 451 pages, sent on request.
The short version
We tested 33,192 Walsin WR and MR general purpose rows against the TCR each sheet prints. MR agrees on 13,552 of 13,552. WR departs on 2,700 of 19,640: 1,104 in the anti-sulfuration series and 1,596 in LF 100ppm. The WR sheet (2016) states 100 ppm to 10 megohm; the MR sheet (2024) states 200 above 1 megohm; 1,518 of the departing rows are consistent with the newer banding. 1,182 rows in LF 100ppm are looser than every band we hold, and 1,596 of 3,872 LF rows are looser than their plain twin. We will not tell you a 100ppm series is 100 ppm. We will show you the string. Qualification stays with you.
Send us the resistor lines off your BOM with the TCR you qualified, and we will mark each position against the sheet we hold. And a question back: when your parametric search returned “100ppm” in the series name, did anyone open the row?
Frequently asked questions
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Does the Walsin export match the datasheet TCR?
For MR, yes: we tested 13,552 non-jumper rows at five sizes and found no row looser than the MR sheet. For WR, no: 2,700 of 19,640 rows at four sizes publish a looser TCR than the WR sheet, 13.7 percent, all in the anti-sulfuration and LF 100ppm series.
What TCR does the Walsin WR sheet print?
It prints 100 ppm per degree Celsius for every resistance above 10 ohm up to 10 megohm, and minus 200 to plus 400 at 10 ohm or below. The sheet is ASC_WR_V24, dated September 2016, and covers WR12, WR08, WR06 and WR04 only.
How does the MR sheet differ on TCR?
It prints three limits instead of two: 100 ppm from above 10 ohm to 1 megohm, 200 ppm above 1 megohm, and minus 200 to plus 400 at 10 ohm or below. The sheet is ASC_MR_V13, March 2024. The 1 to 10 megohm band is the one place the two sheets disagree.
Does LF 100ppm in a Walsin series name mean 100 ppm?
Not on every row. In the WR LF 100ppm series at the four sheet sizes, 2,276 of 3,872 rows publish ≦±100, 58.8 percent. The rest publish ≦±200 on 896 rows, ≦±300 on 140 and -300～+500 on 560, each looser than the plain series twin at the same size and value.
Why does the TCR column not sort as numbers?
Because it holds text. The five strings at these sizes use ≦ (U+2266) and a full-width tilde (U+FF5E), for example ≦±100 and -200～+400. A numeric sort or cast fails or silently drops rows. Normalise the strings to a lower and upper limit before comparing.
Which Walsin resistor sizes does this test cover?
WR at 1206, 0805, 0603 and 0402, and MR at 1210, 1206, 0805, 0603 and 0402, because those are the sizes the two sheets tabulate. 42,362 other general purpose rows, at 0201, 01005 and the large sizes, and all SR rows, have no sheet we hold, so we did not test them.
Can I rely on this instead of the datasheet?
No. This is a comparison of two documents Walsin published, not a measurement. Request the sheet covering your part number, confirm the TCR against it, and qualify in your own circuit. We hold two chip resistor sheets among 28 Walsin datasheets, and none for the LF 100ppm series.