X5R to X7R MLCC Swap: 412 of Walsin’s 731 X5R Part Numbers Have an X7R Twin, but Only 571 of 7,254 X7R Go the Other Way

An X5R to X7R MLCC swap is possible for 412 of Walsin’s 731 X5R part numbers, 56.4 percent, and impossible for the other 319. We matched every row on size, capacitance, rated voltage and tolerance letter. The reverse swap, X7R to X5R, works for only 571 of 7,254.

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Your selector told you the dielectric was a drop-down. It is not. It is a filter that empties on contact: the moment you hold size, value, voltage and tolerance fixed and change only the dielectric, 319 of Walsin’s X5R part numbers have nowhere to go. Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the parametric export published by Walsin Technology (Walsin), and this post is written from 00_ALL_MLCC_parts_combined.xlsx. We parsed all 24,026 rows, removed the QA row and repeated part numbers, and built a twin test. Every part number below is real. We will not tell you that an X7R part is a drop-in for your X5R part. We will show you which four fields match and which do not.

How many Walsin X5R MLCC have an X7R part with the same size, value, voltage and tolerance?

412 of 731, which is 56.4 percent. We took the 23,593 distinct part numbers with a readable capacitance, removed the 28 whose capacitance column disagrees with the code in their own part number, and left 23,565. A twin is a row of the other dielectric with an identical case size, capacitance, rated voltage and tolerance letter. Those 412 X5R part numbers share 754 pairs with 571 distinct X7R part numbers, so most have one twin and some have as many as six.

Direction	Part numbers tested	With a twin	Share	Match / mismatch against a drop-in assumption
X5R to X7R	731	412	56.4%	Mismatch for 319 X5R part numbers: no X7R row carries the same four fields
X7R to X5R	7,254	571	7.9%	Mismatch for 6,683 X7R part numbers: no X5R row carries the same four fields
X6S to X5R	127	100	78.7%	Mismatch for 27
X6S to X7R	127	36	28.3%	Mismatch for 91
X7S to X5R	20	18	90.0%	Mismatch for 2
X8G to NPO	209	193	92.3%	Mismatch for 16
X8R to X7R	26	26	100%	Match on all four fields for every X8R row
NPO to X7R	15,194	1,737	11.4%	Mismatch for 13,457 NPO part numbers

We have not seen this counted anywhere. The twin count is a property of the export, not of physics: it says whether Walsin lists a part of the other dielectric at the same four coordinates, and nothing about whether the circuit tolerates the change. For what the dielectric letters mean, see NP0 vs X7R vs X5R.

Is the swap symmetric, or does it only work one way?

One way, and the gap is 56.4 percent against 7.9 percent. X5R is the smaller population, so a twin search from X5R finds a partner for 412 of 731 part numbers. From X7R the same search finds a partner for 7.9 percent of 7,254 part numbers. The asymmetry is the finding. A buyer who tests an X7R-to-X5R change on a handful of mainstream lines will conclude it works, and be wrong for 6,683 other lines.

The X6S, X7S and X8G rows show the same shape. 100 of 127 X6S part numbers have an X5R twin, because both sit in the 0201 to 1210 General Purpose range. Only 36 have an X7R one. All 26 X8R part numbers, which sit in the high temperature series, have an X7R twin, and 193 of 209 X8G part numbers have an NPO twin. The mismatch there is the dielectric letter and the operating temperature range, not the electrical coordinates.

Where are the X5R parts that have no X7R twin?

At the extremes of capacitance and at the lowest voltages. We counted the 319 orphans in 00_ALL_MLCC_parts_combined.xlsx by case size, voltage and capacitance, and the smallest case, 01R5, loses 27 of 32 X5R part numbers.

Case size	X5R part numbers	With an X7R twin	Share	Match / mismatch against a size-for-size swap
01R5	32	5	15.6%	Mismatch — 27 orphans at the smallest case
0201	178	86	48.3%	Mismatch for 92
0402	151	80	53.0%	Mismatch for 71
0603	127	77	60.6%	Mismatch for 50
0805	101	64	63.4%	Mismatch for 37
1206	94	67	71.3%	Mismatch for 27
1210	48	33	68.8%	Mismatch for 15

By voltage, all 14 X5R part numbers rated 4 Vdc have no X7R twin, and 95 of the 155 rated 6.3 Vdc have none. The export lists only 3 X7R part numbers at 4 Vdc, and none shares a size, value and tolerance with any of the 14. By capacitance, 67 of the 124 X5R part numbers at 10 µF and above have no X7R twin, because the X7R ceiling in the export is 47 µF and X5R reaches 220 µF. 1206X227M6R3, 220 µF at 6.3 Vdc, has nowhere to go. By tolerance, the 11 X5R part numbers with tolerance letter Z, minus 20 to plus 80 percent, have no twin at all.

What does a twin still not match?

Dielectric, always, and often thickness and series. We compared the 754 pairs field by field. The listed thickness differs in 271 of them, 35.9 percent, and the series differs in 407. The General Purpose approval sheet, 01_General_Purpose.pdf, page 4 of 21, states the operating temperature as minus 55 to plus 85 degrees Celsius for X5R and minus 55 to plus 125 for X7R, and the capacitance characteristic as plus or minus 15 percent for both. The export carries no DC-bias column, so what happens to capacitance under bias is not in the data we hold. See MLCC DC bias and voltage derating.

X5R part	X7R twin	Size, value, voltage, tolerance	Listed thickness (X5R / X7R)	Your incumbent part	Match / mismatch
0603X105K160	0603B105K160	0603, 1 µF, 16 Vdc, 10%	0.80 +0.15/-0.10 mm / same	___	Match on size, value, voltage, tolerance, thickness and series. Mismatch on dielectric
0402X104K500	0402B104K500	0402, 100 nF, 50 Vdc, 10%	0.50 ±0.20 mm / 0.50 ±0.05 mm	___	Match on the four fields. Mismatch on dielectric and on listed thickness
1210X106K250	1210B106K250	1210, 10 µF, 25 Vdc, 10%	2.50 ±0.30 mm / 2.00 ±0.20 mm	___	Match on the four fields. Mismatch on dielectric and on thickness by 0.5 mm
TT31X105K250	1206B105K250	1206, 1 µF, 25 Vdc, 10%	0.85 ±0.10 mm / 1.15 ±0.15 mm	___	Match on the four fields. Mismatch on dielectric, series (Low Profile TT against General Purpose) and thickness
SH18X105K250	0603B105K250	0603, 1 µF, 25 Vdc, 10%	0.80 ±0.30 mm / 0.80 +0.15/-0.10 mm	___	Match on the four fields. Mismatch on dielectric and on termination (soft termination against standard)
1206X227M6R3	none	1206, 220 µF, 6.3 Vdc, 20%	1.60 +0.30/-0.10 mm / n/a	___	Mismatch — no X7R row at this value

The columns we left blank are yours. Thickness decides whether the replacement clears a shield can or a stencil. Series decides whether a termination or a qualification route changes. The tolerance strings in this export are not clean either; we read the letter in the part number instead, for the reason set out in the tolerance notation post.

How many of the X5R lines in Hong Kong stock have an X7R twin on the shelf?

Seven of 51. We matched the Hong Kong snapshot dated 23 September 2026 against the export. Of 51 X5R part numbers in stock, 19 have an X7R twin anywhere in the export, and 7 have one on the shelf. All seven pairs are General Purpose, and all seven sit between 0402 and 0805: 0402X104K250 with 0402B104K250, 0402X104K500 with 0402B104K500, 0402X105K6R3 with 0402B105K6R3, 0603X105K160 with 0603B105K160, 0603X105K250 with 0603B105K250, 0603X474K100 with 0603B474K100, and 0805X105K250 with 0805B105K250.

That is a snapshot of part numbers, not pieces, and it will move. For the live position, use our ready-stock check. To cross a whole list at once, use the free cross-reference tool — up to 500 part numbers, or an Excel or CSV file.

What should you check before you change the dielectric on a bill of materials?

Five things, in this order, and each one is measurable from a document we can send you. The first removes 319 X5R part numbers from the discussion before any electrical question is asked.

1. Confirm the twin exists. Do not assume it. Nine in ten X7R part numbers, 6,683 of 7,254, have no X5R twin.
2. Compare listed thickness. It differed in 271 of 754 pairs.
3. Read the operating temperature on the series sheet. X5R tops out at plus 85 degrees Celsius on the General Purpose sheet. X7R reaches plus 125.
4. Check capacitance under bias. The export has no column for it, and we hold no bias curve for any part.
5. Qualify in your own circuit. Confirm against both datasheets. We hold 28 Walsin datasheets, 451 pages, and will send the one covering your part number.

The wider picture of how Walsin’s range is organised is on the MLCC product page. How the part number encodes each of these fields is covered in how to read a Walsin MLCC part number.

The short version

412 of 731 Walsin X5R part numbers (56.4 percent) have an X7R part with the same size, capacitance, rated voltage and tolerance letter. 571 of 7,254 X7R part numbers (7.9 percent) have an X5R one. All 14 X5R part numbers at 4 Vdc, 95 of 155 at 6.3 Vdc, 67 of 124 at 10 µF and above, and all 11 with tolerance letter Z have no X7R twin. A twin still differs on dielectric, and on listed thickness in 271 of 754 pairs. In Hong Kong stock as at 23 September 2026, 7 of 51 X5R lines have an X7R twin on the shelf. We will not call any of them interchangeable. We will show you the fields. Qualification stays with you.

Send us the X5R lines on your bill of materials and we will return each one with its twins, its mismatched fields and what was on the shelf. And a question back: when you last changed a dielectric on a drawing, which of the four fields did you check before you signed it?

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Frequently asked questions

<!– wp:rank-math/faq-block {"questions":[{"id":"faq-question-01","title":"How many Walsin X5R MLCC have an X7R part with the same size, value, voltage and tolerance?","content":"412 of 731 distinct X5R part numbers, 56.4 percent, in the export dated 2026. The match is on case size, capacitance, rated voltage and tolerance letter. The other 319 have no such X7R row, mostly at 4 and 6.3 Vdc, at 10 µF and above, and at the 01R5 case.","visible":true},{"id":"faq-question-02","title":"Can I swap X7R for X5R as easily as X5R for X7R?","content":"No. Only 571 of 7,254 X7R part numbers, 7.9 percent, have an X5R row with the same size, value, voltage and tolerance letter. The swap is far more available in one direction than the other, so test the direction you need.","visible":true},{"id":"faq-question-03","title":"Does a twin have the same operating temperature range?","content":"No. The General Purpose approval sheet, page 4 of 21, states minus 55 to plus 85 degrees Celsius for X5R and minus 55 to plus 125 for X7R. The dielectric is the one field a twin never matches. Check the sheet for your series, because other series may state different ranges.","visible":true},{"id":"faq-question-04","title":"Does a twin have the same thickness?","content":"Often not. We compared 754 X5R and X7R pairs: the listed thickness differs in 271 of them, 35.9 percent. For example, 0402X104K500 lists 0.50 plus or minus 0.20 millimetres and its twin 0402B104K500 lists 0.50 plus or minus 0.05.”,”visible”:true},{“id”:”faq-question-05″,”title”:”Which X5R parts have no X7R twin at all?”,”content”:”All 14 rated 4 Vdc, 95 of 155 rated 6.3 Vdc, 67 of 124 at 10 µF and above, 27 of 32 at the 01R5 case, and all 11 with tolerance letter Z. 1206X227M6R3, 220 µF at 6.3 Vdc, is one. The export’s X7R ceiling is 47 µF.”,”visible”:true},{“id”:”faq-question-06″,”title”:”Are the twins in Hong Kong stock?”,”content”:”Seven pairs are. Of 51 X5R part numbers in the 23 September 2026 snapshot, 19 have an X7R twin in the export and 7 have one on the shelf. The snapshot counts part numbers, not pieces, and changes; use the ready-stock page for the current position.”,”visible”:true}],”listStyle”:””,”titleWrapper”:”h3″,”titleCssClasses”:””,”contentCssClasses”:””,”sizeSlug”:””} –>

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