MLCC Load Life Test: 23 of Walsin’s 26 MLCC Datasheets Run 1,000 Hours, 2 Run 2,000, and 1 of 27 Switches the Voltage Off

An MLCC load life test is 1,000 hours on 23 of the 26 Walsin MLCC datasheets we hold, 2,000 hours on two, and absent from one. We read every load-life row ourselves. The temperature, the voltage multiple and the allowed capacitance change all move between sheets, and three sheets state no absolute temperature at all.

Venatech Limited, an authorised Walsin distributor in Hong Kong, holds 28 Walsin Technology (Walsin) datasheets — 451 pages, 26 for multilayer ceramic capacitors and 2 for chip resistors. For this post we extracted the text of all 451 pages and read one row in each document: the load-life row, the one that tells you how long the part was held hot and energised before anybody wrote a specification. Every part number below is real and checked against our master set. We will not tell you a part is equivalent. We will show you where it differs.

How many of Walsin’s 26 MLCC datasheets state an MLCC load life test at all?

25 of 26. We checked all 26 and only 00_MLCC_Application_Guide.pdf, 12 pages, carries no load-life row — it is a mounting and derating document, not an approval sheet. The remaining 25 split cleanly on naming: 21 call the test High Temperature Load (Endurance) and 4 call it Operational Life, referenced to MIL-STD-202 Method 108. No document uses both names.

The 2,000-hour exception is not something we inferred. Page 61 of 00_MLCC_Full_Catalogue.pdf prints the general figure as 1000+24/-0 hrs and then footnotes it: “Excluding RH, UF series 2000+24/-0 hrs.” Catalogue and individual sheets agree, which is worth saying because they do not always. Source: Walsin’s MLCC catalogue.

Three sheets — 11_Automotive_MT.pdf page 18, 12_Soft_Term_Automotive_ST.pdf page 12 and 13_Soft_Term_Automotive_VT_VW80808.pdf page 9 — state the load-life temperature as “Maximum Operating Temperature ±3°C” and leave you to resolve it from the part’s own temperature characteristic. 22_Feed_Through_FT.pdf does the same with a tighter band, “± 2 °C”. These are four of the sheets an engineer is most likely to quote into a qualification plan, and they are the four that print no number.

Which Walsin series states the hardest load life condition we hold?

The RH microwave series, and it is not close. Page 10 of 07_Microwave_High_Reliability_RH.pdf states 150 ± 3 °C, 2,000 +24/−0 hours, at 200 % of rated voltage for parts rated 10 V up to but not including 500 V. That is twice the hours of 23 other sheets, 25 °C hotter than the 125 ± 3 °C most of them use, and at double the rated voltage throughout.

UF matches the hours but not the heat: page 6 of 08_Microwave_Narrow_Tolerance_UF.pdf states 125 ± 3 °C, 2,000 +24/−0 hours, 200 % of rated. HT matches the heat but not the hours: page 8 of 15_High_Temperature_HT_150C.pdf states 150 ± 3 °C, 1,000 +24/−0 hours, 200 % of rated.

There is a commercial catch on RH and we would rather you heard it here. RH has a full 13-page approval sheet in our library and zero rows in Walsin’s parametric export, so no RH part number exists for us to quote, cross or offer. It is one of six series in that position — see six MLCC series that return zero parts. The toughest load-life condition we hold sits on a series the catalogue cannot currently sell you.

Which real part numbers sit behind each load life condition?

Eight, drawn from eight different approval sheets, every one present in our master part-number set. We measured each row against the strictest load-life condition in the library — RH’s 150 °C, 2,000 hours, 200 % of rated voltage — and stated the differences field by field rather than calling anything a like-for-like swap.

Two rows deserve a sentence. S242B101K502 has its endurance written against IEC 60384-14 clause 4.14 rather than a d.c. multiple, with a 1,000 Vrms excursion applied once an hour for 0.1 second on top of the steady stress — harder in one respect, looser in acceptance. TT31X225K100 is the part whose sheet permits a quarter of the capacitance to disappear and still pass.

How much capacitance is a part allowed to lose after the load life test?

It depends which sheet governs your part, and the spread is wider than most selectors admit. Of the 25 load-life rows, 19 state a Class II capacitance-change limit and they state three different numbers: ±12.5 % on 15 sheets, ±20 % on the three safety-certified sheets, and ±25 % on the low-profile TT sheet. The remaining 6 sheets cover Class I dielectrics only and state ±3.0 % or ±0.3 pF, whichever is larger.

The safety row is the one to take to a design review. A ±20 % post-endurance drift on an X1/Y2 class capacitor is 1.6 times the ±12.5 % the same manufacturer applies to its general-purpose X7R, and the sheet cites IEC 60384-14 clause 4.14 for it directly. If your filter corner depends on that capacitor holding its value at end of life, design to the limit in the governing sheet, not the one you remember. That same series carries the certificate numbers you can check without asking us: UL file E182369, TUV R50381780, and CQC20001280137.

Note also the low-voltage exceptions. Several sheets, including 01_General_Purpose.pdf page 18, widen the X7R and X5R allowance to ±25 % at or below 6.3 V, and again at 10 V for 0603 at or above 4.7 µF, 0402 at or above 1 µF and 0201 at or above 0.1 µF. The headline ±12.5 % does not cover the bulk parts a point-of-load rail is built from.

Which Walsin datasheet switches the voltage off during its load life test?

Exactly one of 27. We counted every load-life row across all 28 documents — 25 on the MLCC side and 2 on the chip resistor side, 27 in total, with only the application guide stating none. 26 of those 27 rows hold the stress on continuously. One does not. Page 9 of the WR general-purpose chip resistor sheet states the endurance test as 1,000 +48/−0 hours “loaded with RCWV or Vmax in chamber controller 70 ± 2 ºC, 1.5 hours on and 0.5 hours off”. At a 75 % duty cycle, 750 of those 1,000 hours carry voltage and 250 do not. We have not seen this counted anywhere.

The automotive resistor sheet does not do this. Page 8 of the MR sheet states Operational Life as 1,000 +48/−0 hours at 125 ± 2 °C and 35 % of operating power, continuously, referenced to MIL-STD-202 Method 108 — and MR06W1005FTL is governed by that row while WR06X1002FTL is governed by the duty-cycled one. Two chip resistors from the same manufacturer, two different definitions of a thousand hours.

What should you ask for before you accept a load life figure for your part number?

Three things, and the first is free. Walsin’s sheets state a test, not a result — “1,000 hours at 125 °C and 200 % of rated” is the condition the series was proved against, not a lifetime. Page 18 of 01_General_Purpose.pdf says so in its own words: typical device lifetime around 10 years, extendable at 80 % of rated voltage or less and 20 °C below maximum operating temperature, with the useful-lifetime data stated as reference only and not guaranteed.

1. Ask which sheet governs your exact part number, and which page. We hold 28 Walsin datasheets, 451 pages. Ask for the one covering your part and it will be in your inbox, not in a brochure — and if no page covers it, you get that answer the same day.
2. Ask for the qualification report if the part is automotive. AEC-Q200 on the MT, ST, VT and RT sheets is stated as compliant and qualified to, never certified, and we will not upgrade Walsin’s own word — see what AEC-Q200 actually certifies.
3. Cross the whole list in one pass. Paste up to 500 part numbers or drop your Excel or CSV into the free cross-reference tool, filter by commercial or automotive grade, and read every stated difference. Then check what is physically in Hong Kong on ready stock — 1,125 part numbers as at 23 September 2026, a dated snapshot and not a live feed. The full capacitor line sits on the Walsin MLCC page.

The short version

25 of our 26 Walsin MLCC datasheets state a load-life test; the 12-page application guide states none. 23 run 1,000 hours and 2 run 2,000 — RH and UF, confirmed by the catalogue’s own footnote. RH states the hardest condition we hold, 150 ± 3 °C for 2,000 hours at 200 % of rated voltage, and returns zero export rows, so it cannot be quoted today. MT, ST and VT state no absolute temperature at all. The post-test Class II capacitance limit takes three values across 19 sheets: ±12.5 %, ±20 % on the three safety sheets, ±25 % on low-profile TT. And exactly one of the 27 load-life rows in 451 pages is duty-cycled. Qualification stays with you; our job is to make sure the number you qualify against is the one printed on the page that governs your part.

Send us the capacitor and resistor lines off your bill of materials and we will return the governing sheet, the page number and the exact load-life row for each one — including the lines where no page exists. And a question back: when your incumbent supplier quotes “1,000 hours”, have you ever asked them at what temperature, at what multiple of rated voltage, and whether the voltage stayed on the whole time?

Frequently asked questions