MLCC Insulation Resistance and Dissipation Factor: 18 of 173 Rows Publish Them

Insulation resistance and dissipation factor, the fields that decide MLCC leakage and self-heating, appear on only 18 of 173 rows in Walsin’s enriched MLCC export. We checked every IR and DF cell in 00_ALL_MLCC_combined.xlsx ourselves. The other 23,428 MLCC part numbers Walsin Technology (Walsin) lists carry neither field in any export we hold.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds this 173-row sample file alongside the 24,026-row main MLCC export and 26 Walsin MLCC datasheets, including 01_General_Purpose.pdf. Every part number and every IR or DF value below is copied straight out of 00_ALL_MLCC_combined.xlsx or that datasheet, and we say which.

How many Walsin MLCC rows publish insulation resistance and dissipation factor?

Eighteen. We counted the filled cells in the IR and DF columns across all 173 rows: both fields are populated together on exactly 18 rows, 10.4%, and empty together on the other 155. Neither field exists at all in the 24,026-row main export, so these 18 are the only IR or DF figures Walsin publishes for MLCC anywhere in our data.

Field checked across 00_ALL_MLCC_combined.xlsx	Rows filled	Share
Dimensions, Capacitance, Tolerance, Rated Voltage	173 / 173	100%
IR (insulation resistance)	18 / 173	10.4%
DF (dissipation factor)	18 / 173	10.4%
TCC, DC Bias 25, Packing, SPQ	0 / 173	0%
IR or DF anywhere in the 24,026-row main export	0 / 24,026	0%

We have not seen this counted anywhere. IR decides leakage current and whether a part holds charge; DF decides how much of the applied signal turns to heat at frequency. Both are missing from 89.6% of the one file that ever carries them.

Which series carry the 18 rows, and which carry none at all?

Eight of the sixteen sampled series carry at least one of the 18 rows; eight carry none. We grouped by series: MT (5 rows), Microwave RF (5), Automotive Soft Term ST (2), Feed Thru FT (2), General Purpose (1), Middle to High Voltage (1), Soft Termination SH (1) and Ultra-small 01R5 (1). Big Sizes, High Q/Low ESR HH, High Temperature HT, Low Profile TT, Automotive MG, Safety S2, Soft Termination SG and Ultra Microwave UF each contribute zero of their 11 sample rows.

There is no size or dielectric pattern across the 18 — NPO (MT15N0R5C500, 0402), X7R (ST18B473K500, 0603) and X5R (FT15X435M4R0, 0402) all appear. Whether a row carries IR and DF looks like which series was sampled, not what the part is.

Do the 18 rows actually clear Walsin’s own insulation resistance floor?

Sixteen of eighteen clear it; two do not. Walsin’s own 01_General_Purpose.pdf approval sheet (page 13, item 5, “Insulation Resistance”) states a baseline floor of 10 GΩ or R×C ≥ 500 Ω·F, whichever is smaller, at room temperature. We read that figure straight off the PDF and checked every one of the 18 rows against it.

Part number	Series	IR as published	DF as published	Match / mismatch vs Walsin’s 10 GΩ floor
MT15N0R5C500	MT (automotive, AEC-Q200)	≧10G-ohm	≦0.244%	Match — meets the floor exactly
ST18B473K500	ST (soft term, AEC-Q200)	≧10G-ohm	≦3%	Match
RF03N0R2A250	RF (microwave)	≧10G-ohm	≦0.248%	Match
0201X101K160	General Purpose	≧10G-ohm	≦3.5%	Match
0805B121K251	Middle to High Voltage	≧10G-ohm	≦2.5%	Match
SH18B101K500	SH (soft term, Ag-poly)	≧10G-ohm	≦2.5%	Match
01R5N100J160	01R5 (ultra-small)	≧10G-ohm	≦0.167%	Match
FT21B103M500	FT (feed-through)	1000MΩmin (1 GΩ)	0.03Ω max	Mismatch — a full decade below the 10 GΩ floor
FT15X435M4R0	FT (feed-through)	25 M-ohmmin (0.025 GΩ)	0.03Ω max	Mismatch — three decades below the 10 GΩ floor

We will not tell you the FT rows are defective parts. Feed-through capacitors are built with a conductive through-line for EMI filtering, and a lower insulation figure can be a legitimate property of that construction, not an error. What we will say is that the two rows fail the one numeric floor Walsin states for general-purpose MLCC, and the General Purpose sheet we are quoting from does not cover FT at all — so the floor itself may simply not apply to this series, and we are flagging rather than asserting either way.

Why does one series’ dissipation factor column hold an impedance, not a percentage?

Because both FT rows read 0.03Ω max in the DF column, and dissipation factor is dimensionless — a ratio, conventionally written as a percentage — never an ohm value. We checked all seven distinct DF strings across the 18 rows: ≦0.244%, ≦0.167%, ≦3%, ≦2.5%, ≦3.5%, ≦0.248% and 0.03Ω max. Six are percentages. One is not.

Why do IR and DF decide leakage and self-heating in the first place?

Because they are the two numbers that describe what a capacitor does when it is not behaving like an ideal one. Insulation resistance sets the leakage current at a given voltage — a timing capacitor or a sample-and-hold hold capacitor with low IR bleeds charge and drifts. Dissipation factor sets how much of the ripple current at frequency turns into heat inside the part rather than being stored and returned — a bulk decoupling capacitor with a high DF runs hotter under the same ripple current and can derate itself further on top of the DC bias loss covered in MLCC DC bias and voltage derating. Neither figure is recoverable from capacitance, tolerance or case size alone, which is exactly why a cross on those fields can match everywhere except the two that govern leakage and heat.

What do you need to request for the other 155 rows, and the other 23,428 part numbers?

The datasheet for the specific series, by name, not the export. We hold 26 Walsin MLCC datasheets and the General Purpose approval sheet alone runs to a full page of voltage- and case-size-dependent IR and DF tables — far more detail than one export column could carry even if it were filled in. For any part number outside the 18 rows above, the export will not tell you IR or DF; the series datasheet, requested by name, is the only route we have.

1. Tell us the series, not just the part number, if leakage or self-heating is the thing you are qualifying against. We will pull the relevant table from the datasheet rather than quote an export cell that does not exist.
2. Cross the rest of the BOM in one pass. Paste up to 500 part numbers or drop your Excel or CSV into the free cross-reference tool, which decodes 18 manufacturers’ part numbers against 800,000+ crossable Walsin part numbers and states every difference field by field.
3. Check Hong Kong stock on ready stock, a dated snapshot as at 23 September 2026, before you commit a qualification slot to a part that is not physically available.

The short version

Insulation resistance and dissipation factor are the two export fields that actually decide MLCC leakage and self-heating, and Walsin’s enriched export publishes both on 18 of 173 sample rows — nowhere else in any file we hold. Sixteen of those 18 clear the 10 GΩ floor stated in Walsin’s own General Purpose sheet; the two Feed Thru rows do not, and the same two rows carry an ohm value in a column meant for a percentage. We have not seen either fact counted before.

Send us the series and the IR or DF threshold your design needs, and we will pull it from the datasheet rather than quote you a blank export cell. For the part-number decode, see How to read a Walsin MLCC part number. The full range is on the Walsin MLCC page.

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Frequently asked questions

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