Inductor rated current by case size does not rise with the footprint in Walsin’s export. We compared the highest rated current at each case size for the same series and the same inductance: 230 of 815 steps to the next larger case publish a lower current, 28.2 percent. Moving from 1008 to 1210 does it on 106 of 128.
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 and nothing here is a qualification claim.
Does a bigger chip inductor case always carry more current at the same inductance?
No, and in the Walsin export it fails more than a quarter of the time. We parsed 4,309 rows with a numeric inductance, a rated current and one of the seven standard case sizes from 0201 to 1812, then took the highest rated current per series, inductance and case size. Of 815 steps to the next larger case, 230 publish a lower figure.
We removed 47 rows first. Rated current of 10 A or more on a chip inductor is not a plausible figure: 30 sit in WLFI, a defect we covered in shielded vs unshielded chip inductors, and 17 sit in the WQCW 0402 ladder, for example WQCW1005Z0GR10TP at 100 nH with 2 ohm of resistance and 30 A. Keeping them would have inflated the count. Removing them does not change which pairs invert in the other 4,309 rows.
How many size steps in the Walsin export run backwards?
230 of 815, and the median inversion is a 21 percent drop. Of the 815 adjacent case-size steps, 585 rise or hold and 230 fall. In the 230, the larger case publishes between 31.6 and 95.2 percent of the smaller case’s current, and in 17 of them it publishes half or less.
| Part, smaller case | Part, larger case | Rated current, smaller | Rated current, larger | Match / mismatch | Your incumbent part (fill in) |
|---|---|---|---|---|---|
WLCW1608HQJ3N3PB, 0603, 3.3 nH |
WLCW2012Z0K3N3PB, 0805, 3.3 nH |
1.9 A | 600 mA | Mismatch — the larger case rates 31.6% of the smaller | |
WLCW2520HQG10NPB, 1008, 10 nH |
WLCW3225Z0G10NPB, 1210, 10 nH |
1.6 A | 600 mA | Mismatch — 37.5% | |
MIP1608P1R0MBP, 0603, 1 uH |
MIP2012P1R0M05BP, 0805, 1 uH |
950 mA | 800 mA | Mismatch — 84.2% | |
MIP20121R0MBE, 0805, 1 uH |
MIP25201R0MBE, 1008, 1 uH |
1100 mA | 1600 mA | Match — the larger case rates higher | |
WLCM0603TNJ10NTB, 0201, 10 nH |
WLCM1005Z0J10NTB, 0402, 10 nH |
250 mA | 0.5 A | Match — the larger case rates higher | |
WLCW3225Z0GR10PB, 1210, 100 nH |
WLCW4532Z0GR10PB, 1812, 100 nH |
1 A | 1.15 A | Match — the larger case rates higher |
The first row is the one to stop on. The 0805 part is bigger in every dimension and thicker, 1.52 mm against 0.9 mm, and it publishes less than a third of the current. We have not seen this counted anywhere. The Size column is a footprint label, not a current ranking.
Which case-size steps invert most often?
The ones where a high-current style stops. We grouped the 815 steps by the pair of case sizes involved. 1008 to 1210 inverts on 106 of 128 steps, 82.8 percent. 0603 to 0805 inverts on 89 of 153. 0402 to 0603 inverts on 22 of 228. 0201 to 0402 and 1210 to 1812 invert on none of 78 and none of 40.
| Step | Steps compared | Steps that invert | Share | Match / mismatch against “bigger case, more current” |
|---|---|---|---|---|
| 0201 to 0402 | 78 | 0 | 0% | Match |
| 0402 to 0603 | 228 | 22 | 9.6% | Mismatch on 22 |
| 0603 to 0805 | 153 | 89 | 58.2% | Mismatch on 89 |
| 0805 to 1008 | 168 | 4 | 2.4% | Match on all but 4 |
| 1008 to 1210 | 128 | 106 | 82.8% | Mismatch on 106 |
| 1210 to 1812 | 40 | 0 | 0% | Match |
| Steps that skip a size | 20 | 9 | 45% | Mismatch on 9 |
Read the middle of the table as a rule: if your design lives at 0805 or 1210 and you hope that stepping up a size buys current, the export says it usually does not. We count that on the highest figure per size, which is the generous reading for the larger case, and the inversion rate still reaches 82.8 percent at 1008 to 1210.
Which series never invert?
Five series, all small. MCI (66 steps), WLCM (66), MCI Automotive (25), MIP (4) and MIP-H (2) show 0 inversions across 163 steps. The four series that share a ladder, WLCW, WCA, WCI and WQCW, invert on 54 of 169, 61 of 157, 55 of 157 and 55 of 147 steps.
The overlap matters. WLCW, WCA, WCI and WQCW repeat the same inductance ladders, covered in 3,146 chip inductors publishing identical data. Counted once per pair of case sizes, inductance and current values, the 230 inversions collapse to 110 distinct ones out of 399 distinct steps. Quote 110 for physical comparisons and 230 for the number of row pairs a script will find. The other inverting series are MIP-P (3 of 3) and WLFW/WFI (2 of 19).
| Series | Steps compared | Inversions | Match / mismatch against “bigger case, more current” |
|---|---|---|---|
| WLCW | 169 | 54 | Mismatch on 54 |
| WCA | 157 | 61 | Mismatch on 61 |
| WCI | 157 | 55 | Mismatch on 55 |
| WQCW | 147 | 55 | Mismatch on 55 |
| WLFW/WFI | 19 | 2 | Mismatch on 2 |
| MIP-P | 3 | 3 | Mismatch on all 3 |
| MCI, WLCM, MCI Automotive, MIP, MIP-H | 163 | 0 | Match |
Does a high-Q style explain the inversions?
Partly. In WLCW, the one series where we could read the style code from the part number, 37 of the 54 inversions have an HQ-style part as the highest-rated row at the smaller case. Yet when we removed every HQ row and re-ran it, the Z0 style alone still inverted on 56 of 157 steps.
So the high-current HQ style explains most inversions but not the whole effect. WLCW1608HQJ3N3PB (HQ, 1.9 A) sits above a Z0 part at 0805 that publishes 600 mA, which is the pattern behind most inversions. HQ rows are only 153 of the 791 WLCW rows we used, so a minority style sets the current ceiling at the smaller sizes, while the Z0 ladders also cross each other.
What should a Hong Kong designer check before moving to a larger footprint?
Check the part, not the size. When we read the ladders, the footprint told us less about current than the style letters in the part number did. For how the families differ, see how rated current relates to saturation current, and note that only 146 inductors publish a saturation current at all.
Three rules, each measured above:
- Never assume a larger case rates more current. 230 of 815 steps say otherwise.
- Treat 1008 to 1210 as the riskiest step. It inverts on 106 of 128.
- Compare thickness as well as footprint. The 0805 part above is thicker than the 0603 part and rates a third of the current.
Run your current part through the free cross-reference tool, and we will show you which fields match and which 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 compared the highest rated current per series, inductance and case size across 4,309 Walsin inductor rows. 230 of 815 steps to the next larger case publish a lower current, 28.2 percent, or 110 of 399 once the repeated ladders are counted once. 1008 to 1210 inverts on 106 of 128; 0201 to 0402 and 1210 to 1812 invert on none. MCI, WLCM, MCI Automotive, MIP and MIP-H never invert across 163 steps. We will not tell you a bigger part carries more. We will show you the number the file holds. Confirm against both datasheets and qualify in your own circuit.
Send us the footprint you are leaving and the one you are moving to, and we will show you the fields that differ. And a question back: when you last moved up a size for current, did you check that the larger part published more?
Frequently asked questions
Does a bigger Walsin chip inductor carry more current?
Not reliably. At the same series and inductance, 230 of 815 steps to the next larger case publish a lower rated current, 28.2 percent. The 1008 to 1210 step inverts on 106 of 128. Check the published rated current of the exact part number, not the footprint.
Which Walsin case-size step inverts most?
1008 to 1210, on 106 of 128 steps, 82.8 percent. Next is 0603 to 0805, on 89 of 153, 58.2 percent. The 0201 to 0402 and 1210 to 1812 steps invert on none of 78 and none of 40.
Which Walsin inductor series never publish a lower current at a larger case?
MCI, WLCM, MCI Automotive, MIP and MIP-H. We compared 163 case-size steps across them and found no inversion. The WLCW, WCA, WCI and WQCW series invert on 54, 61, 55 and 55 steps because they share a ladder that mixes styles.
How many of the inversions are distinct?
110 of 399 distinct steps. WLCW, WCA, WCI and WQCW repeat the same inductance ladders, so the 230 row-level inversions collapse once each pair of case sizes, inductance and current values is counted a single time. Quote 110 for physical comparisons and 230 for row pairs.
Why did you remove 47 rows?
Because a rated current of 10 amps or more on a chip inductor is not plausible. 30 of the rows are in the WLFI series and 17 are in the WQCW 0402 ladder, such as a 100 nanohenry part with 2 ohms of resistance and 30 amps. Keeping them would have inflated the count.
Is there a datasheet to check these rated currents against?
We hold 28 Walsin datasheets, 451 pages, and none covers an inductor. Thin film, inductor, disc, RF, MOV and antenna lines have no datasheet in our file, so the export is the only figure we can show you and it should be confirmed against Walsin’s own site.
Can Venatech tell me which Walsin part suits my footprint?
We can show the fields that match and the fields that differ between your part and a Walsin part through the free cross-reference tool. We state which fields match and which differ, and qualification stays with you, in your own circuit.