Heat Pump Inverter Components for the Netherlands: 26 of 24,026 Walsin MLCC Reach 100 nF Above 1,000 Vdc

We parsed all 24,026 rows of Walsin’s MLCC export. Only 26 reach 100 nF at 1,000 Vdc or above, and exactly one is in the Middle to High Voltage series. Heat pump inverter components for a 230 Vac Dutch mains need that ceiling, a varistor and a wide-terminal resistor. We hold no varistor datasheet.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, writes this from three Walsin Technology (Walsin) files: 00_ALL_MLCC_parts_combined.xlsx at 24,026 rows, Walsin_MOV_ALL.xlsx at 379 rows, and Thick_Film_Wide_Terminal_Power_Chip_Resistor__1of1.xlsx at 4,294 rows. Every part number is real. On the varistor line we hold no datasheet at all, and that gap is stated rather than papered over.

What does a 230 Vac Dutch mains input need from Walsin’s varistor line?

A 275 Vac part, and there are exactly 17 of them. We measured the varistor export against a 230 Vac nominal mains: the Max Working Volt. column carries 35 distinct values, 230 Vac is one of them with 17 parts, and 275 Vac — the usual choice once you allow for supply swell — is another with 17. All 17 at 275 Vac share one varistor voltage of 430 Vdc. What separates them is the disc diameter and the peak current, which runs from 400 A to 80,000 A. That is a 200:1 span on one working voltage, and it is ours and already published.

Part number	Series	Disc size	Max working voltage	Peak current	Match / mismatch for a 230 Vac heat pump input
SR361K14D	Standard (D)	14 mm	230 Vac	4,500 A	Mismatch — 230 Vac leaves no headroom for supply swell
SR431K05D	Standard (D)	5 mm	275 Vac	400 A	Mismatch — smallest body, lowest surge capability of all 17
SR431K14D	Standard (D)	14 mm	275 Vac	4,500 A	Match on working voltage and a common disc size for a domestic input
SR431K20D	Standard (D)	20 mm	275 Vac	6,500 A	Match; mismatch — larger footprint and lead pitch than the 14 mm part
SR431K14E	Super High Energy (V)	14 mm	275 Vac	8,000 A	Match on size and voltage; 1.8x the surge of the 14 mm D part
SR431K34RD	Industrial	34 mm square	275 Vac	80,000 A	Mismatch — industrial body, far beyond a domestic unit’s input

Every figure in that table is the export’s own value. We hold no varistor datasheet, so none of it is confirmed against a Walsin specification sheet, and the clamping behaviour that actually decides whether your downstream rectifier survives is not in the file. Confirm each number against Walsin’s own published specification before design-in.

Do we hold a varistor datasheet for any of these parts?

No — zero of 379. We checked our own library: 28 Walsin datasheets, 451 pages, of which 26 are MLCC sheets and 2 are chip resistor sheets. There is no varistor sheet, no disc-capacitor sheet, no inductor sheet and no antenna sheet. For the whole 379-row varistor line the parametric row is the only published figure we hold, and we will not pretend otherwise.

So for varistors the honest route is Walsin’s own site rather than us: the specifications live on Walsin’s own product site at passivecomponent.com, and that is where a clamping voltage, an energy rating in joules and a response time have to be read. We will tell you what we do not have. Most distributors will not, and that is the whole reason this paragraph exists.

How much DC-link capacitance can you get at 1,000 Vdc?

Far less than the voltage rung suggests. A 230 Vac single-phase heat pump inverter rectifies and boosts to a DC link in the high hundreds of volts, so 630 Vdc and 1,000 Vdc are the two rungs a designer weighs. We measured both across all 24,026 MLCC rows. At exactly 630 Vdc, 63 rows reach 100 nF or more. At 1,000 Vdc and above, only 26 rows do — and exactly one of them is in the Middle to High Voltage series.

Series holding a row at 100 nF or more and 1,000 Vdc or above	Rows	Largest value present
Soft Termination SH (Ag-poly)	13	220 nF at 2220
Big Sizes 1825/2220/2225	10	220 nF at 2225
Automotive Soft Term ST (AEC-Q200)	2	100 nF at 1825
Middle to High Voltage (200 V–4 kV)	1	100 nF at 1812
Every other MLCC series in the export	0	—

We have not seen this counted anywhere. The single Middle to High Voltage part is 1812B104K102 — 1812, X7R, 100 nF, ±10%, 1,000 Vdc, 2.50 mm thick. Step down one rung and the picture changes completely: 1210B104K631 and 1812B474K631 show the 630 Vdc shelf reaching 100 nF at 1210 and 470 nF at 1812. The practical reading is that a 1,000 Vdc DC-link ceramic above 100 nF means a soft-termination or large-case part, not a Middle to High Voltage part.

One of the 26 was on our 23 September 2026 Hong Kong snapshot: 2220B104K102, a 2220 X7R 100 nF at 1,000 Vdc. It is also published on two export rows at two thicknesses, 2.00 mm and 2.50 mm, under the one code. SH43B104K102 is the soft-termination route at 1812 and the same rating. Stock is a dated snapshot and moves, so check the current position before you plan against it.

Which wide-terminal power resistors suit a snubber or a bleeder?

A 4,294-row shelf on three case sizes, and one of the three has no tight-TCR option. We read the whole wide-terminal export: 1,708 rows at 1225 (3264 metric) rated 2 W, 1,708 at 0612 (1632) split between 1 W and 3/4 W, and 878 at 1020 (2550) rated 1 W. Resistance runs from 0.1 Ω to 1 MΩ, tolerance is ±1% on 3,497 rows and ±5% on 797. The wide-terminal geometry exists because it moves heat into the board, which is exactly what a bleeder across a DC link has to do.

Part number	Series	Case size	Rated power	Resistance, tolerance	TCR	Match / mismatch for a 10 kΩ DC-link bleeder
WK25L1002FTL	Wide Terminal Power	1225 (3264)	2 W	10 kΩ, ±1%	≦±200 ppm/°C	Match on value and the highest power rating on the shelf
WF25L1002FTLJ	Wide Terminal Power	1225 (3264)	2 W	10 kΩ, ±1%	≦±100 ppm/°C	Match on all four; mismatch — half the TCR, different prefix
WK20L1002FTL	Wide Terminal Power	1020 (2550)	1 W	10 kΩ, ±1%	≦±200 ppm/°C	Mismatch — half the power, and no tight-TCR option exists at 1020
WF12L1002FTLJ	Wide Terminal Power	0612 (1632)	1 W	10 kΩ, ±1%	≦±100 ppm/°C	Mismatch — 0612 geometry at 1 W, tight TCR available

The ≦±100 ppm/°C grade appears on 1,476 of the 4,294 rows, 738 at 1225 and 738 at 0612, and on zero 1020 rows. That count is ours and already published; we re-ran it today and it is unchanged. If your bleeder needs ±100 ppm/°C, the 1020 footprint is out before you look at a value. We will not tell you a part is equivalent. We will show you where it differs.

What does the varistor export not tell you at all?

Three of the four things that decide a mains surge design. We read every column header in Walsin_MOV_ALL.xlsx: Part Number, Series, Size, Max Working Volt., Varistor Voltage, Tolerance, Peak Current, Packing, SPQ and MOQ. Ten columns, and the last three are empty on all 379 rows, which leaves seven carrying data. There is no clamping voltage column, no energy rating in joules, no response time and no capacitance. The Tolerance column reads ±10% on all 379 rows, so it discriminates nothing.

That is not a complaint about Walsin’s export; it is a statement of what a cross-reference can and cannot do on this line. A varistor selection needs the clamp level against your downstream silicon and the joule rating against your expected surge energy. Neither is in the file, and we hold no sheet containing them. Those two figures have to come from Walsin’s own site, and we flag every one of them.

Is peak current a free choice, or is it set by the disc diameter?

Set by the diameter, almost entirely. We grouped all 379 rows by Size and counted the distinct Peak Current values in each. The 5 mm, 7 mm, 10 mm, 14 mm and 20 mm diameters offer three each — one per series family. The 18 mm, 25 mm, 32 mm, 40 mm and 53 mm diameters offer exactly one peak current value each. So above 20 mm the only way to change surge capability is to change the body size, and the 34 mm square is the sole exception with two values, 40,000 A and 80,000 A.

The two smallest diameters carry a second constraint we have published before: 5 mm and 7 mm stop at 420 Vac, while every diameter from 10 mm upward reaches 680 Vac and 53 mm reaches 750 Vac. For a 230 Vac domestic heat pump that limit is not binding. For the same manufacturer’s three-phase 400 Vac commercial unit it is, and the board has to grow before the rating can.

What should a Dutch heat pump design team do with this?

Separate the two halves of the input stage, because we can serve them very differently. On MLCC and chip resistors we hold the datasheet and can show you the row it came from. On varistors we hold nothing, and the right answer is Walsin’s own specification plus your own qualification.

1. Cross the ceramic and the resistors in one pass. Paste up to 500 part numbers or drop your Excel or CSV 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, including filters for soft termination and high temperature.
2. Check the dated shelf. Ready stock is a snapshot as at 23 September 2026, not a live feed. 149 of its 1,125 part numbers sit in the Middle to High Voltage MLCC series and 254 are chip resistors.
3. Ask us for the two sheets we hold and the one we do not. The MLCC series datasheet comes by return. For varistors we will point you at Walsin’s own site and put the sheet on our request list, which is the honest sequence.

For the varistor families themselves, see MOV varistor series selection: D, E, V and industrial. For the wide-terminal case sizes, see Wide terminal power resistors: 1225, 1020 and 0612. The varistor range is on the Walsin MOV range page.

The short version

A 230 Vac Dutch heat pump inverter pulls on three Walsin lines and we can document two of them. The varistor export holds 379 rows, 17 of them at 275 Vac sharing a 430 Vdc varistor voltage and spanning 400 A to 80,000 A on diameter alone — and we hold no varistor datasheet at all, so every one of those figures is flagged and the clamping voltage and joule rating are not in the file. On the DC link, only 26 of 24,026 MLCC rows reach 100 nF at 1,000 Vdc or above and exactly one is in the Middle to High Voltage series, against 63 rows at 630 Vdc. On the bleeder, the wide-terminal shelf is 4,294 rows across three case sizes, and the ≦±100 ppm/°C grade reaches 1225 and 0612 but not 1020. Qualification stays with you.

Send us the mains input and DC-link lines off your heat pump BOM and we will come back with Walsin candidates field by field, the MLCC and resistor figures sourced to the datasheet we hold and the varistor figures marked as unconfirmed, with the Hong Kong position as at 23 September 2026 beside each. Has any distributor told you which of your parts they cannot document? Ask them, and compare the answer with this page.

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Frequently asked questions

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