Inductor Rated Current vs Inductance: 136 of 1,548 Steps Rise in Walsin’s Export, and 30 Also Raise SRF, Counted for Hong Kong Designers

Inductor rated current vs inductance should slope one way: more inductance means more turns, more resistance and less current. We walked 41 Walsin series-and-size ladders and counted 1,548 steps. On 136 of them, 8.8 percent, the next inductance up publishes a higher rated current. Six series never do it.

Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the 5,410-row chip inductor export published by Walsin Technology (Walsin). This post is written from its Series, Size, Inductance, Unit and Rated Current columns, with the QA test row Test123999 excluded. Every part number is real. We hold no Walsin inductor datasheet, so these are export figures.

Should rated current fall every time inductance rises?

As a first-order rule inside one series and case size, yes. More inductance means more winding, more DC resistance and more heating at the same current. We took the highest rated current at each inductance value and compared it with the next value up. In 1,548 steps across 41 groups with at least five inductance values, the current is higher 136 times.

We removed 47 rows first: those with a rated current of 10 A or more, 30 in WLFI and 17 in the WQCW 0402 ladder. Those are not plausible chip inductor figures, and we covered the WLFI defect in reading Rdc and the broader size picture earlier. Keeping them would only have added noise. The rule we tested is the generous one: the best current at each value, not the worst, so a rise is not an artefact of picking a weak row.

How many inductance steps in the Walsin export raise the rated current?

136 of 1,548, with a median rise of 33 percent. The 136 rises sit in five wirewound and multilayer families plus single steps in four more. The median step multiplies the current by 1.33. 33 of them are 1.5 times or more, 11 are 2 times or more, and the largest is 3.0 times.

WLCW, WCA, WCI and WQCW repeat the same inductance ladders, covered in 3,146 chip inductors publishing identical data. Counted once per case size, inductance pair and current pair, the 136 rises collapse to 69 distinct steps. We have not seen this counted anywhere. Quote 69 for physical steps and 136 for rows.

Which series never raise it?

Six, and a few more raise it once. MAP (5 steps), MCI Automotive (67), MCI-TM (67), MIP (6), WLFI (13) and WQCM (25) show no rise in 183 steps. MCI and WLCM, the two big multilayer lines, raise it once each in 138 and 139 steps.

We opened the 0201 ladder, which has no rise at all. In WLCM at 0201, 61 inductance values run from WLCM0603Z0B0N3TB at 0.3 nH with 850 mA down to WLCM0603TGJ39NTB with 120 mA, and the current never goes up. The single MCI rise is MCI1005HQ12NGHBP at 12 nH with 0.4 A to MCI1005HQ13NGHBP at 13 nH with 0.6 A, 1.5 times.

How big are the rises, and do they cross a style change?

Some do, and some do not. In WLCW, the one series where the style code reads cleanly from the part number, 52 steps rise. 18 cross from Z0 to HQ style, 24 stay inside Z0 and 10 stay inside HQ. So a third of the rises are two ladders spliced together, and two thirds are inside one style.

Do the steps that raise current also raise SRF?

Sometimes, and the overlap is smaller than you might expect. We matched the 136 current rises against the 144 steps where the minimum self-resonant frequency also rises. They share 30 steps, 22 percent of the current rises. The other 106 steps raise current alone.

That overlap is a check on the story. If every break were one sub-family splicing into another, current and SRF would move together far more often. Because they do not, the ladders carry more than one mechanism: style splices, binning of individual rows and plain ladder noise. For the SRF side of the same ladders, see the SRF explainer, and note that the SRF(min) column states no unit.

What should a Hong Kong designer do with a ladder that rises?

Pick the part number, not the position on the ladder. When we read the steps, the neighbour of your value was often a different style, and the export does not tell you so. For how the families differ, see how to tell Walsin inductor series apart.

Three rules, each measured above:

1. Do not interpolate rated current between two inductance values. 136 of 1,548 steps run the wrong way.
2. If you need the highest current at a value, check every row at that value. The best row sets the ladder, and it may be a different style from its neighbours.
3. Prefer WLCM or MCI for a clean ladder. One rise in 139 and 138 steps, against 52 in 273 for WLCW.

Run your part through the free cross-reference tool, and we will show you the fields that match and the fields that differ. The range is on the inductor products page, and what is held in Hong Kong is on ready stock, 1,125 part numbers as at 23 September 2026, a dated snapshot and not a live feed.

The short version

We walked 41 Walsin inductor ladders, 1,548 steps in all, after removing 47 implausible rows. The highest rated current rises with the next inductance value on 136 steps, 8.8 percent, or 69 distinct steps once repeated ladders are counted once. Six series never do it, and the WLCM line does it once in 139 steps. 30 of the rises also raise SRF. In WLCW, 18 of 52 rises cross from Z0 to HQ style. We will not tell you a ladder is monotonic. We will show you the number the file holds. Confirm against both datasheets and qualify in your own circuit.

Send us your inductor part number and the current you run it at, and we will show you which fields differ. And a question back: when you picked the next inductance up, did you check what happened to the current?

Frequently asked questions