Walsin MLCC for Medical and Pharmaceutical Instrumentation in Ireland: the Dielectric and Voltage Ladder

For a medical or pharmaceutical instrument built in Ireland, the MLCC decision is the dielectric and voltage ladder, and the evidence behind it. Venatech Limited, an authorised Walsin distributor in Hong Kong, publishes the ladder here as measured data, plus the two part numbers in Walsin’s catalogue that contradict their own dielectric code.

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Walsin Technology (Walsin) publishes a 24,026-row MLCC parametric export and 26 MLCC datasheet PDFs, and Venatech holds both. The counts below cover the 13,193 distinct part numbers in the six series outside the automotive and soft-termination families. Every part number is real. Counts are of part numbers, never of pieces. Nothing here is a regulatory opinion.

Does Venatech have an entity or stock in Ireland?

No. There is no Venatech entity, office, warehouse or stock in Ireland. The operating entities are Venatech Limited in Hong Kong, the Shenzhen trading entity, VENATECH PTE LTD in Singapore and the Jiangmen factory in Guangdong, with Chengdu in preparation. Hong Kong is the authorised Walsin distribution entity and the origin for every shipment to Ireland.

The Irish consignee is therefore the importer, and the obligations that attach to placing a device on the market stay with the device manufacturer. What crosses the water with the parts is the documentary chain, and that does not need a local warehouse.

What does a medical or pharmaceutical instrument need from an MLCC that a consumer board does not?

Three things, in this order. A dielectric whose capacitance behaviour over temperature and bias is known rather than adequate. A rated voltage with real derating headroom, because the instrument’s calibration depends on the capacitance staying where it was when it was calibrated. And a documented lot, because a design history file records which parts were in which build.

What we can supply precisely is the catalogue. So here it is.

What does Walsin’s dielectric and voltage ladder actually look like?

Narrow at the top. Across the 8,330 distinct General Purpose part numbers, the dielectric choice collapses as rated voltage rises, and above 50 Vdc there is effectively no Class II option other than X7R.

Rated voltage	NP0	X7R	X5R	X6S	X7S	Match / mismatch vs “I can pick any dielectric”
4 Vdc	0	3	11	24	0	Mismatch — no NP0 at all
6.3 Vdc	6	84	121	37	5	Match — all five present
10 Vdc	433	402	154	29	5	Match — all five present
16 Vdc	576	520	131	17	4	Match — all five present
25 Vdc	898	558	112	16	3	Match — all five present
35 Vdc	0	8	5	2	0	Mismatch — no NP0, 15 part numbers in total
50 Vdc	1,881	778	57	1	1	Match, but X6S and X7S are one part number each
100 Vdc	960	467	1	1	3	Mismatch — one X5R and one X6S part number exist
200 Vdc	6	0	0	0	0	Mismatch — NP0 only
250 Vdc	4	2	0	0	0	Mismatch — effectively NP0 only
630 Vdc	2	0	0	0	0	Mismatch — NP0 only, two part numbers

The two singletons at 100 Vdc are 0805A105M101 and 1210S475K101 — one 1 µF X5R and one 4.7 µF X6S. If a calibrated instrument front end needs a microfarad at 100 Vdc in a Class II dielectric, that is the whole General Purpose selection, and 0805A105M101 has a second problem discussed below. Above 100 Vdc in General Purpose there are only 14 part numbers in total and 12 of them are NP0.

Note also that 35 Vdc is almost absent: 15 part numbers across the entire General Purpose series and not one of them NP0. A design that derates a 24 V rail to a 35 V part is designing into a 15-part corner. For what the dielectric codes commit the part to, see NP0 vs X7R vs X5R MLCC dielectric.

Can I read the dielectric straight off the part number?

Almost always, and the exceptions matter. The character after the case size is the dielectric code: N for NP0, B for X7R, X for X5R, S for X6S, A for X7S, G for X8G, R for X8R, F for Y5V. We checked that character against the Dielectric column on every one of the 13,193 part numbers.

Dielectric character	Part numbers carrying it	Dielectric column reads	Match / mismatch
N	7,551	NP0 on all 7,551	Match
B	4,689	X7R on 4,688, NP0 on 1	Mismatch on one part number
X	674	X5R on all 674	Match
S	127	X6S on all 127	Match
G	102	X8G on all 102	Match
R	26	X8R on all 26	Match
A	22	X7S on 21, X5R on 1	Mismatch on one part number
F	2	Y5V on both	Match

Unique to Venatech’s data. The dielectric character inside the part number agrees with the Dielectric column on 13,191 of the 13,193 part numbers in Walsin’s six non-automotive MLCC series. Exactly two disagree. 0201B8R2B250 carries B, which reads X7R on the other 4,688 B part numbers, while its own row reads NP0 — and the export separately lists 0201N8R2B250, identical in case size, dielectric, capacitance, tolerance, rated voltage, length, width, thickness and thickness symbol, differing only in that one character. 0805A105M101 carries A, which reads X7S on the other 21 A part numbers, while its own row reads X5R — and its ±10% sibling 0805A105K101, the same 0805 1 µF 100 Vdc part, reads X7S. Checked character by character against the column across all 13,193.

For a calibrated instrument that is not a cosmetic defect. X7R and NP0 behave differently over temperature and under bias, and X5R and X7S differ in upper category temperature. Either the character or the column is wrong on each of those two part numbers, and nothing in the export says which.

Is there any part number whose rated voltage is published twice?

One, in 23,601 distinct codes. 2225N103J101 appears on two rows of Walsin’s export with two different rated voltages: 100 Vdc on one and 1,000 Vdc on the other.

Field	2225N103J101, row A	2225N103J101, row B	Match / mismatch
Case size	2225	2225	Match
Dielectric	NP0	NP0	Match
Capacitance	10 nF	10 nF	Match
Tolerance	±5%	±5%	Match
Rated voltage	100 Vdc	1,000 Vdc	Mismatch — a factor of ten
Thickness	1.60 ± 0.20 mm	2.00 ± 0.20 mm	Mismatch — 0.40 mm
Thickness symbol	G	K	Mismatch

Unique to Venatech’s data. 2225N103J101 is the only part number in Walsin’s entire 24,026-row MLCC export that is published with two different rated voltages. Walsin’s own voltage suffix is two significant digits followed by a decade exponent, so 101 decodes as 100 V and 102 as 1,000 V — which makes the 1,000 Vdc row the one that cannot be right on this code. Measured by grouping all 24,026 rows on part number and counting distinct values per field: rated voltage conflicts on one code, capacitance on one, dielectric on none.

For an Ireland-built instrument that figure is the derating calculation. A 10 nF part believed to be 1,000 Vdc and actually 100 Vdc is not a sourcing error, it is a field failure. And there is no second code to fall back on: the 102 voltage suffix does exist at 2225 in NP0 — on 2225N102J102, 2225N222J102 and 2225N472J102 among others — but no 2225 NP0 10 nF part number carries it. The published voltage steps for that value are 2225N103J631 at 630 Vdc and 2225N103J202 at 2,000 Vdc, with the disputed 2225N103J101 between them. Confirm the rating in writing before anyone commits.

What does the parametric export not state at all?

Everything a qualification engineer needs after the five electrical fields. The export has 16 columns: part number, series, size, dielectric, capacitance, tolerance, rated voltage, length, width, thickness, termination, packing, SPQ, remark, thickness and symbol. There is no insulation resistance, no dissipation factor, no operating temperature range, no ageing rate, no bias characteristic and no failure-rate figure anywhere in it.

Three of those 16 columns — packing, SPQ and the second thickness column — are empty on all 24,026 rows, and the termination column carries a tolerance string rather than a termination material wherever it is populated. Venatech has published both findings before; they are ours and they are already in the public record. The consequence for a medical instrument file is simply stated: the electrical limits have to come from the series datasheet, and the lot data has to come from the shipment. For the code conventions behind the ladder, see tolerance, TCR and dielectric codes decoded.

What traceability can Venatech put behind a part shipped to Ireland?

Authorised-source provenance, original sealed manufacturer packaging, full lot and date code traceability, and a Certificate of Conformity on request naming the part number and the lot and date code that shipped. Sourcing is authorised-only, direct from the manufacturer, with no open-market channels.

What we will not do is certify anything ourselves. Venatech holds no ISO 9001 and no IATF 16949 certification and makes no qualification claim of its own. Walsin’s own certifications are Walsin’s; where its datasheets say AEC-Q200 they say compliant, not certified, and only seven of the 26 MLCC datasheets mention the standard at all. We will request the qualification report and the series substance declaration from Walsin and pass through what Walsin issues, unaltered. Browse the range on the Walsin MLCC product page.

The short version

The dielectric ladder narrows fast: above 50 Vdc in General Purpose there is one X5R part number and one X6S part number, and above 100 Vdc there are 14 part numbers in total. 35 Vdc has 15. The dielectric character is reliable on 13,191 of 13,193 part numbers, and the two exceptions — 0201B8R2B250 and 0805A105M101 — are both flagged here. One code in the whole export, 2225N103J101, is published at two rated voltages ten times apart. The export states none of the electrical limits a qualification needs; the datasheet does. Traceability we can evidence; certification we will not claim.

Send the Ireland BOM and we will return, per line, the series, the dielectric read from both the code and the column, the voltage headroom, the datasheet we hold, and anything that has to be confirmed with Walsin in writing before design-in.

Two things you can do now. Cross a part — one number or a whole spreadsheet, and each result names what matches and what differs. And ready stock is a dated snapshot of what is physically in Hong Kong, which is what an Irish build schedule needs to be set against.

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Frequently asked questions

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Three ways to get this answered today

1. Cross a part, free. Paste up to 500 part numbers, or drop an Excel or CSV file, into the free cross-reference tool. It is matched against Walsin’s published catalogue and returns candidates field by field, with every difference from your original stated rather than hidden. Filter by commercial or automotive grade, or for soft termination, high temperature, safety certified, high Q / low ESR or low profile. There is no login and no charge.

2. Send the whole BOM. Upload a BOM and request a quote and we will come back line by line — including the lines we cannot help with, which is usually the more useful half of the answer.

3. Check the shelf before you commit. Ready stock shows what was physically in Hong Kong as at 23 September 2026. It is a dated snapshot, never a live feed, and quantities are never permanent.

Why take our word for any of this? Don’t — check it.

Venatech Limited (威納電子有限公司) is an authorised Walsin Technology distributor in Hong Kong. Confirm that with Walsin rather than with us. On the safety capacitor series we hold UL file E182369, which is searchable in UL’s own public database, together with TUV certificates R50381780 and R50195920 and CQC CQC20001280137 and CQC20001280136, against EN 60384-14:2023, IEC 60384-14:2023 and UL 60384-14. We hold 28 Walsin datasheets, 451 pages, and we will send the one covering your part number. Shipments arrive in original sealed Walsin packaging with lot and date-code traceability, and a certificate of conformity is available per shipment on request.

We will also tell you what we do not hold, which no competitor publishes. REACH, SVHC, conflict minerals, PFAS, China RoHS, ISO 9001, IATF 16949, PPAP, IMDS and a Declaration of Conformity appear nowhere in those 451 pages. You would rather hear that from us now than from your own supplier-approval team later. AEC-Q200 is compliant in Walsin’s own words and never certified, we hold no manufacturer’s end-of-life or allocation list for any brand, and qualification in your own circuit stays with you. We will not tell you a part is equivalent. We will show you where it differs.

Venatech Limited · Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong · (852) 2628 4777 · Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation.