Chip Resistor Rated Power vs Datasheet: Walsin MR04, MR06 and MR08 Differ From the Sheet on 1,936 Rows Each, 5,948 of 33,192 in All

The chip resistor rated power in Walsin Technology (Walsin) export files differs from the approval-sheet table on 5,948 of 33,192 tabulated WR and MR rows. MR04, MR06 and MR08 account for 1,936 each, and WR12 for 140. Every MR mismatch sits in three part-number suffixes: TLV, FTR and JTR. The standard FTL and JTL rows all agree.

Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the chip resistor parametric exports and the two chip resistor approval sheets that go with them. This post is written from 27 general purpose export files (75,628 rows) read in full, tested against the rated-power tables printed on page 3 of the WR and MR sheets. Every part number below is real. Every count is of part numbers, not pieces. The question is the one a buyer asks before crossing an automotive 0805: which wattage does this exact part number carry?

How many Walsin WR and MR rows differ from the datasheet’s rated power?

5,948 of 33,192, or 17.9 percent. We took 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), and compared the export’s Rated Power column with the sheet’s maximum dissipation at 70 °C for that size. WR agrees on 19,500 rows. MR agrees on 7,744 of 13,552.

The sheets are Walsin_WR_General_Purpose_Chip_Resistor.pdf (ASC_WR_V24, September 2016) and Walsin_MR_Automotive_Thick_Film_Chip_Resistor.pdf (ASC_MR_V13, March 2024). Two thirds of MR04, MR06 and MR08 rows carry a rating below the sheet, and every one is rated lower, never higher. The 34 jumper rows are tested separately: 6 of them disagree too, 2 each at MR04, MR06 and MR08.

Which part-number suffixes carry the lower rating?

Three suffixes, and nothing else. We split the 8,712 MR04, MR06 and MR08 rows by the last three characters of the part number. The standard FTL and JTL rows (968 per size) match the sheet on every one. The TLV rows (968 per size) and the FTR and JTR rows (968 per size) are all rated one step lower. The FTR and JTR rows sit in a separate export series, named “LF 100ppm (Automotive)” in the Series column. The TLV rows share the plain “(Automotive)” series name with the standard parts.

We have not seen this counted anywhere. The same three suffixes appear at all five MR sizes, yet only the three smallest carry a lower rating. MR10 has no FTR or JTR rows at all, and at MR12 all three suffixes agree with the sheet. A rule such as “TLV means a derated variant” is therefore true at 0402, 0603 and 0805 and false at 1206 and 1210. The suffix does not carry the information; the size does.

Is the lower MR rating the same as the WR rating?

Yes, at every size. The rating on the 1,936 mismatching rows equals the WR sheet’s rating for the same case size: 1/16 W at 0402, 1/10 W at 0603 and 1/8 W at 0805. The export has, in effect, put a WR-rated resistor under an MR part number. Whether that is deliberate we do not know.

Read MR08X1003FTL against MR08X1003FTLV. They share a prefix, a size, a tolerance and a resistance. One is rated 250 milliwatts and the other 125. A filter on series and size returns both; a filter on the Rated Power column separates them. Our earlier post on the automotive MR, SR and AEC-Q200 split sets out what the MR prefix does and does not tell you. The rating also interacts with the working-voltage ceiling, which we counted in chip resistor working voltage vs rated power.

What about the 140 WR12 rows rated 1/2 W?

They are 1206 parts the WR sheet rates at 1/4 W and the export rates at 1/2 W. All 140 carry the type letter F and a trailing “FN” in the part number, run from 1 ohm to 10 ohm, and split 115 at plus or minus 1 percent and 25 at plus or minus 5 percent. An example is WR12F1R00FTL FN. The WR sheet’s ordering key on page 6 defines two type codes only, X and W, so the sheet cannot confirm or deny a 1/2 W part with an F type.

This is the opposite direction from the MR rows: the export rates these above the sheet, where the MR rows are rated below it.

Is any mismatching row in Hong Kong stock?

None. We matched the 1,125 part numbers in the ready-stock snapshot as at 23 September 2026 against the 33,192 tested rows. 165 fall inside the tested population, all WR, split 78 WR06, 53 WR04, 19 WR08 and 15 WR12. None of the 165 is among the 5,948 mismatches, and the snapshot holds no MR part number at all.

A snapshot is a dated picture, not a live feed. Quantities move and we do not quote them here; use the ready stock page and the enquiry form. Of the 1,125 part numbers, 254 are chip resistors, and 237 of those begin WR.

How should a buyer check rated power before crossing an MR part?

Compare the Rated Power field of the exact part number, not the series: 5,808 of 13,552 MR rows differ from the sheet, and the series name does not say which. Three steps, none of them a column filter:

1. Read the suffix against the size. At 0402, 0603 and 0805, a TLV, FTR or JTR tail means the export rating is one step below the MR sheet. At 1206 and 1210 it does not.
2. Put the wattage in your BOM line. If your design needs 250 milliwatts at 0805, MR08X1003FTL carries it and MR08X1003FTLV does not.
3. 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 each difference from your original, rated power included.

Qualification stays with you. For the case-size ladder see chip resistor power rating by case size, and for the range the Walsin chip resistor page. We hold 28 Walsin datasheets, 451 pages, two of them for chip resistors, and send the sheet for your part number on request. Confirm against both datasheets and qualify in your own circuit.

The short version

Walsin’s export disagrees with its own sheet on rated power for 5,948 of 33,192 tabulated WR and MR rows. MR04, MR06 and MR08 contribute 1,936 each, all in the TLV, FTR and JTR suffixes, and WR12 contributes 140 rated above its sheet. Each lower MR rating equals the WR rating at the same size. MR10, MR12 and the other WR sizes agree on every row. None of the 165 tested part numbers in Hong Kong stock as at 23 September 2026 is a mismatch.

Send us the resistor lines off your BOM with the wattage you need, and we will mark each as agreeing or disagreeing with the sheet we hold. And a question back: when your drawing says “MR08”, which wattage did the engineer who wrote it assume?

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