Chip Resistor Reliability Tests: Walsin’s WR Sheet Lists 12, the MR Sheet 16, and Only 6 Share a Name, Checked for Germany

Walsin Technology (Walsin) prints 12 chip resistor reliability tests on its WR sheet and 16 on its MR automotive sheet. We counted both: 6 share a name, 6 are WR-only, 10 are MR-only. WR cites no AEC-Q200 method; MR cites three. A German qualification file needs that split.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds both resistor approval sheets: ASC_WR_V24 (SEP 2016) and ASC_MR_V13 (Mar – 2024), ten pages each. This post is written from the test-and-requirements pages of those two PDFs, read line by line, and from the 75,628 general purpose rows in Walsin’s chip resistor export. Every part number below is real. The question is the one a German supplier-approval questionnaire asks first: which tests were run, and under what conditions, for the part number on my bill of materials?

How many reliability tests does each Walsin chip resistor sheet list?

12 on WR and 16 on MR, counting each named row once, including the electrical row that holds the DC resistance and TCR measurement. We opened the “TEST AND REQUIREMENTS” pages of both sheets and listed every named row. WR names 12 rows across pages 7 and 8; MR names 16 across pages 7 and 8. Six names appear on both, six on WR alone, ten on MR alone. The 12 and 16 each include the electrical row, which is a measurement rather than a stress test.

Test as named on the sheet	In WR (SEP 2016)	In MR (Mar 2024)	Match / mismatch
Electrical characteristics (DC resistance, TCR)	Yes	Yes	Match in name
Resistance to soldering heat	Yes	Yes	Match in name, mismatch in condition
Solderability	Yes	Yes	Match in name, mismatch in condition
Temperature cycling	Yes	Yes	Match in name, mismatch in condition
High temperature exposure	Yes	Yes	Match in name and condition
Short time overload (STOL)	Yes	Yes	Match in name and condition
Bending strength	Yes	No	Mismatch — WR only
Adhesion	Yes	No	Mismatch — WR only
Load life in humidity	Yes	No	Mismatch — WR only
Load life (endurance)	Yes	No	Mismatch — WR only
Insulation resistance	Yes	No	Mismatch — WR only
Dielectric withstand voltage	Yes	No	Mismatch — WR only
Moisture resistance	No	Yes	Mismatch — MR only
Bias humidity	No	Yes	Mismatch — MR only
Operational life	No	Yes	Mismatch — MR only
Mechanical shock	No	Yes	Mismatch — MR only
Board flex	No	Yes	Mismatch — MR only
Terminal strength	No	Yes	Mismatch — MR only
Vibration	No	Yes	Mismatch — MR only
Thermal shock	No	Yes	Mismatch — MR only
ESD	No	Yes	Mismatch — MR only
Sulfuration test	No	Yes	Mismatch — MR only

Add a column for your own incumbent part’s datasheet and tick the rows it prints. A test absent from a sheet we hold is “not in the documents we hold”, a statement about our library and not about the part.

Which of the shared tests use the same conditions?

Two of the six, and only one of those two is a true stress condition. We compared the printed conditions of all six shared rows. High temperature exposure is identical on both sheets, 1000 hours at 155 degrees Celsius plus or minus 3, and short time overload is identical, 2.5 times the rated continuous working voltage for 5 seconds. The other four differ, and temperature cycling differs by a factor of 200.

Shared test	WR condition	MR condition	Match / mismatch
Resistance to soldering heat	260 °C ±5, 10 ±1 s, JIS C5201-1 clause 4.18	270 °C ±5, 10 ±1 s, MIL-STD-202 method 210	Mismatch — 10 °C higher on MR
Solderability	235 °C ±5, 2 ±0.5 s dip	Bake 155 °C for 4 h then 235 °C for 5 s; steam 1 h then 260 °C for 7 s	Mismatch — MR has two procedures
Temperature cycling	−55 / +155 °C, 30 min dwell, 5 cycles	−55 / +155 °C, 5 to 10 min dwell, 1000 cycles	Mismatch — 5 against 1000 cycles
High temperature exposure	1000 +48/−0 h, 155 °C ±3, no load, MIL-STD-202 method 108	1000 +48/−0 h, 155 °C ±3, no load, MIL-STD-202 method 108	Match on condition; limit differs (below)
Short time overload	2.5 × RCWV or maximum overload voltage, 5 s	2.5 × RCWV or maximum overload voltage, 5 s	Match
TCR (electrical row)	Test temperature stated: −55 °C or +155 °C	Reference temperature stated; no test-temperature value in the text we extracted	Mismatch — see the flag below

Same condition does not mean same limit. On high temperature exposure the WR sheet prints two pass limits by tolerance grade, a resistance change of (1%+0.1) for 1% parts and (2%+0.1) for 5% parts; the MR sheet prints one, (1%+0.05). 7 of the 12 WR rows print two limits, one per tolerance grade; 2 of the 16 MR rows do. The unit of the added constant did not survive text extraction on either sheet, so read it from the PDF.

Which tests appear in one sheet and have no counterpart in the other?

By name, 16 of the 22 distinct test names sit on one sheet only. By function the gap is smaller. We paired each single-sheet row with the nearest row on the other sheet. Four WR-only rows have an MR counterpart under another name, two do not, and six of the ten MR-only rows have none. That pairing is our reading of the sheets, not a statement by Walsin.

WR-only row	Nearest MR row	Condition difference	Match / mismatch
Bending strength	Board flex	3 mm for 10 s (5 mm on WR04) against 2 mm for 10 s	Mismatch — deflection differs; MR cites AEC-Q200-005
Adhesion	Terminal strength	5 N for 10 s against 1 kg for 60 s	Mismatch — force and time both differ; MR cites AEC-Q200-006
Load life in humidity	Bias humidity	40 °C, 90 to 95% RH, loaded, 1.5 h on 0.5 h off, against 85 °C, 85% RH at 10% of operating power	Mismatch — 45 °C and 5 to 10 points of humidity apart
Load life (endurance)	Operational life	70 °C ±2 at rated voltage, 1.5 h on 0.5 h off, against 125 °C ±2 at 35% of operating power	Mismatch — 55 °C apart, loaded differently
Insulation resistance	none	1 min at maximum overload voltage, 10 gigohm minimum	Mismatch — WR only
Dielectric withstand voltage	none	1 min AC at maximum overload voltage	Mismatch — WR only

The MR rows with no WR counterpart are moisture resistance, mechanical shock (1500 g, half sine), vibration (5 g, 20 minutes, 3 orientations), thermal shock (300 cycles), ESD (1.0 kV, 0.5 kV for 0402) and the sulfuration test (ASTM B-809, 60 °C, 500 hours). Both sheets count three 1000-hour rows each; MR adds 500 hours of sulfuration and ten 24-hour moisture cycles on top.

Which test standards does each sheet cite?

Different families. We counted every method citation in the test pages of both sheets. The WR sheet cites JIS C5201-1 on 11 of its 12 rows and MIL-STD-202 on 1. The MR sheet cites MIL-STD-202 on 8 of its 16 rows, JIS C5201-1 on 2, and AEC-Q200 on 3, JESD22 on 1, J-STD-002 on 1 and ASTM B-809 on 1. The two sheets share a preamble that names IEC 115-8, but their method bases differ.

Method family	Rows on WR (of 12)	Rows on MR (of 16)	Match / mismatch
JIS C5201-1:1998	11	2	Mismatch
MIL-STD-202	1	8	Mismatch
AEC-Q200 method numbers (-002, -005, -006)	0	3	Mismatch
JESD22, J-STD-002, ASTM B-809	0	3	Mismatch

The MR sheet also states on page 1 that it is “Automotive & Military Compliant” and lists “Automotive AEC Q-200 & Military MIL-STD Compliant” as a feature. Walsin’s word is compliant, and so is ours. The WR sheet makes no such statement. Neither sheet is a qualification report, and we hold none.

What can a German automotive buyer not read from the WR sheet?

Four things. We read all ten pages of ASC_WR_V24. It contains no AEC-Q200 reference, no vibration, shock, ESD or sulfuration row, no RoHS exemption named, and it is dated SEP 2016, 121 months before our 14 October 2026 review. That matters because the part number does not tell you which sheet applies.

We parsed all 234,815 rows of the chip resistor export: 45,315 carry a WR prefix, and 20,578 of those sit in series whose name says Automotive, which is 45.4% of the WR prefix. The MR prefix is not the only automotive route, and the sheet that carries the automotive test list is the MR one.

Part number	Series named in the export	Rated power	Sheet that lists its size	Your incumbent	Match / mismatch
WR06X1002FTL	General Purpose Chip Resistor	1/10 W	WR (0603, 1/10 W)		Reference
MR06X1002FTL	General Purpose Chip Resistor (Automotive)	1/8 W	MR (0603, 1/8 W)		Mismatch — power 1/8 W against 1/10 W, 16 test rows against 12
WR06X1002FTLJ	General Purpose Chip Resistor (Automotive)	1/10 W	WR lists the size; the series name says Automotive		Mismatch — series says Automotive, the WR sheet has no AEC-Q200 row
WR06X1002FTLV	General Purpose Anti-Sulfuration Chip-Resistor (Automotive)	1/10 W	WR lists the size; no sulfuration row on WR		Mismatch — sulfuration test is on MR only
WR12X1002FTL	General Purpose Chip Resistor	1/4 W	WR (1206, 1/4 W)		Match on case size, value and tolerance with MR12X1002FTL
MR12X1002FTL	General Purpose Chip Resistor (Automotive)	1/4 W	MR (1206, 1/4 W)		Match on power; mismatch on test list

We will not tell you a part matches. We will show you which sheet speaks for it. Not in the documents we hold: a qualification report, PPAP, IMDS or VDA documentation for any resistor series. If your questionnaire asks, request the report for the exact part number.

What did the earlier count of these two sheets get wrong?

Our own March comparison counted 8 WR tests. We recounted for this post and the figure is 12. The recount adds high temperature exposure, bending strength, adhesion and short time overload, which an earlier Venatech table listed as MR-only or left out. The same earlier table said MR adds a second TCR test temperature; in the text we extracted, it is the WR sheet that states one. The earlier post, WR and MR series compared, field by field, needs correcting on both points.

We have not seen these two sheets’ test lists counted anywhere else, which is why a wrong number from us would travel. The wider automotive picture, including the 17,442 MR and 12,871 SR rows, is in Walsin automotive chip resistors: MR, SR and the AEC-Q200 split.

The short version

WR prints 12 reliability test rows and MR 16. Six names are shared, six are WR-only and ten are MR-only. Of the six shared, only high temperature exposure and short time overload carry the same condition: temperature cycling is 5 cycles against 1000. WR cites JIS C5201-1 on 11 rows and no AEC-Q200 method; MR cites MIL-STD-202 on 8 rows and AEC-Q200 on 3. 20,578 WR-prefix rows sit in series named Automotive, so the prefix does not tell you which test list applies. We hold 28 Walsin datasheets, 451 pages; ask for the sheet covering your part number and it will be in your inbox. What is in Hong Kong is on ready stock, 1,125 part numbers as at 23 September 2026, a dated snapshot. The range sits on the chip resistor page. Paste your incumbent into the free cross-reference tool and confirm against both datasheets and qualify in your own circuit.

Send us the resistor part number on your approval list and we will tell you which of the two sheets, if either, speaks for it. And a question back: when your supplier says “automotive”, which of the 16 rows did they mean?

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Frequently asked questions

<!– wp:rank-math/faq-block {"questions":[{"id":"faq-question-01","title":"How many reliability tests does the Walsin WR datasheet list?","content":"12 named rows, including the electrical row that holds DC resistance and TCR. We counted them on pages 7 and 8 of ASC_WR_V24, dated SEP 2016. Eleven cite JIS C5201-1 and one cites MIL-STD-202. None cites an AEC-Q200 method number, and none covers vibration, mechanical shock, ESD or sulfuration.”,”visible”:true},{“id”:”faq-question-02″,”title”:”How many does the Walsin MR automotive datasheet list?”,”content”:”16 named rows in ASC_MR_V13, dated Mar – 2024. Eight cite MIL-STD-202, three cite AEC-Q200 method numbers, two cite JIS C5201-1, and one each cites JESD22, J-STD-002 and ASTM B-809. Walsin describes the series as compliant with AEC-Q200, not certified, and we use the same word.”,”visible”:true},{“id”:”faq-question-03″,”title”:”Do WR and MR use the same temperature cycling test?”,”content”:”No. Both cycle between minus 55 and plus 155 degrees Celsius, but WR specifies 30 minutes at each extreme for 5 cycles, and MR specifies a 5 to 10 minute dwell for 1000 cycles. That is 200 times more cycles on MR. Neither sheet reports a cycle count at which parts fail.”,”visible”:true},{“id”:”faq-question-04″,”title”:”Is a WR-prefix part number automatically a general purpose, non-automotive part?”,”content”:”No. Of 45,315 WR-prefix rows in Walsin’s export, 20,578 sit in series whose name says Automotive, and 24,737 sit in non-automotive series. The prefix alone does not select the datasheet. Read the Series column for the exact part number and ask for the sheet that covers it.”,”visible”:true},{“id”:”faq-question-05″,”title”:”Does the WR sheet test sulfuration resistance?”,”content”:”Not in the document we hold. The sulfuration test, ASTM B-809 at 60 degrees Celsius for 500 hours, appears as a named row on the MR sheet only. 10,659 WR-prefix rows sit in a series named Anti-Sulfuration, so request the test evidence for the exact part number rather than assuming a sheet covers it.”,”visible”:true},{“id”:”faq-question-06″,”title”:”Does Venatech hold a qualification report for these resistors?”,”content”:”Not in the documents we hold. We hold 28 Walsin datasheets, 451 pages, two of them for chip resistors, and none is a qualification report. PPAP, IMDS and VDA documentation are likewise not in our library. A report for your exact part number is a request to Walsin, and nothing has been requested in writing yet.”,”visible”:true}],”listStyle”:””,”titleWrapper”:”h3″,”titleCssClasses”:””,”contentCssClasses”:””,”sizeSlug”:””} –>

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