A chip inductor part number style code is a two-character field that no Walsin export column carries. We counted it on 4,119 rows. In 319 cells, parts share series, size, inductance and tolerance and still differ in that code, and in all 319 the minimum Q differs. Filter on the four published fields and you get several parts.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the inductor export file published by Walsin Technology (Walsin): 14 columns and 5,410 rows once the QA row Test123999 is removed. We hold no Walsin inductor datasheet, so the file is the only specification we can show you. This post is written from that file. A selector that narrows by Series, Size, Inductance and Tolerance ought to land on one part. We tested whether it does, on every row. Every part number below is real and every count is repeatable.
What is the two-character style code in a Walsin chip inductor part number?
It is the pair of characters after the four-digit size block, and it is in no column. We read it on 4,119 nanohenry and microhenry rows. There are 11 distinct codes: Z0, Z2 and A0 on the WL and WQ chip series, HQ, HZ, HH, TG, TN and TM on the MCI series, and CP and CG on WCI and WCA. WLCW2012HQJ6N2PB carries HQ; WLCW2012Z0J6N2PB carries Z0.
The export has 14 columns: part number, series, size, size in millimetres, thickness, inductance, impedance, unit, tolerance, Q minimum, SRF, RDC, rated current and saturation current. The style code is not among them. We hold no Walsin document that defines it, so we do not state what any of the 11 codes stands for.
How many specification cells does the style code make ambiguous?
319 of 3,635, which is 8.8 percent. We defined a cell as one combination of Series, Size, inductance value and Tolerance, and counted the cells holding more than one style code. 319 cells hold 2 or 3 codes, 156 with two and 163 with three, covering 803 parts, which is 19.5 percent of the 4,119 decodable rows. We have not seen this counted anywhere: one part in five sits in a cell the published fields cannot resolve.
| Series label | Codes held | Cells with 2+ codes | Match / mismatch against “four fields, one part” |
|---|---|---|---|
| WLCW Series | Z0, HQ |
111 | Mismatch — 111 cells return 2 parts |
| WLCM Series | Z0, TG, TN, Z2 |
106 | Mismatch — 106 cells return 2 to 4 parts |
| MCI Series | HQ, TG, TN |
102 | Mismatch — 102 cells return 2 to 4 parts |
| WCI and WCA Series | CP, CG |
0 | Match — the two codes never share a cell |
| WQCW, WQCM, WQQC, MCI-TM, MCI Automotive | one or two, never sharing | 0 | Match |
Two thirds of the affected cells are at 0603 (0201) size: 208 of 319, with 79 at 1608, 22 at 2520 and 10 at 2012. The smallest case size is where the most parts hide.
What differs between the parts that share one cell?
Everything the engineer cares about. We compared the columns across the parts in each of the 319 cells. The minimum Q differs in all 319 cells, the SRF in 293, the DC resistance in 281, the rated current in 231 and the thickness in 111. In 179 cells the highest Q is at least twice the lowest.
| Column | Cells where it differs | Share of 319 | Match / mismatch if you assumed the parts were interchangeable |
|---|---|---|---|
| Q Min | 319 | 100.0% | Mismatch in every cell |
| SRF(min) | 293 | 91.8% | Mismatch in nine cells out of ten |
| RDC | 281 | 88.1% | Mismatch in almost nine |
| Rated Current | 231 | 72.4% | Mismatch in seven out of ten |
| Thickness (mm) | 111 | 34.8% | Mismatch in one cell in three |
| Inductance, Tolerance, Size, Series | 0 | 0.0% | Match — by construction |
The first four are the numbers a radio-frequency designer or a power designer picks a part on. All four are in the file. None of them is a selector field, which means the file tells you the parts differ and gives you nothing to choose between them with except their part numbers.
What does the worst cell look like?
A 2012 WLCW at 6.2 nH, where one part has three times the resistance and 2.7 times less current. In the cell for series WLCW, size 2012(0805), 6.2 nH and plus or minus 5 percent, there are two parts. WLCW2012Z0J6N2PB publishes Q 50, 0.11 ohm and 600 mA; WLCW2012HQJ6N2PB publishes Q 88, 35 milliohm and 1.6 A. Four published fields are identical. The part number differs in two characters.
| Part number | Series | Size | Inductance | Tolerance | Q Min | RDC | Rated current | Thickness | Match / mismatch against WLCW2012Z0J6N2PB |
|---|---|---|---|---|---|---|---|---|---|
WLCW2012Z0J6N2PB |
WLCW | 2012 | 6.2 nH | 5% | 50 | 0.11 ohm | 600 mA | 1.52 mm | reference |
WLCW2012HQJ6N2PB |
WLCW | 2012 | 6.2 nH | 5% | 88 | 35 milliohm | 1.6 A | 1.45 mm | Mismatch on Q, RDC, current, thickness and SRF; match on the four selector fields |
WLCW1608Z0J5N6PB |
WLCW | 1608 | 5.6 nH | 5% | 15 | 0.15 ohm | 700 mA | 1.02 mm | reference for the next row |
WLCW1608HQJ5N6PB |
WLCW | 1608 | 5.6 nH | 5% | 48 | 0.036 ohm | 1.7 A | 0.9 mm | Mismatch — Q 3.2 times higher, RDC 4.2 times lower, 0.12 mm thinner |
WLCM0603Z0B0N6TB |
WLCM | 0603 | 0.6 nH | 0.1 nH | 4 | 0.08 ohm | 800 mA | 0.3 mm | reference for the next two rows |
WLCM0603TGB0N6TB |
WLCM | 0603 | 0.6 nH | 0.1 nH | 11 | 0.08 ohm | 850 mA | 0.3 mm | Mismatch on Q, SRF and current, match on RDC and thickness |
WLCM0603TNB0N6TB |
WLCM | 0603 | 0.6 nH | 0.1 nH | 14 | 0.07 ohm | 850 mA | 0.3 mm | Mismatch — a third answer to the same four fields |
The WLCW 1608 row is the sharpest case we found for resistance: the HQ part is 4.2 times lower, the largest RDC ratio of any cell, against a median ratio of 1.2. We do not call any of this an error. It is a field the export left out, and the maker evidently intended the parts to differ. The error would be to treat the four published fields as a key.
Does the Series column resolve the ambiguity?
No, and that is the part that surprises people. The label WLCM Series holds four codes, the label MCI Series holds three and WLCW Series holds two. Across those three labels, 319 cells return more than one part for a four-field filter. The series label separates families of parts; the style code separates parts inside a family.
Two labels do the opposite and are clean: MCI-TM holds one code, TM, on 172 rows, and MCI Automotive Series holds HZ and HH but never in the same cell. So the label is a clean split in some series and no split in others, and nothing in the export says which is which. The twin-prefix effect, where the same data appears under a WLCM and an MCI part number, is a separate matter and is in chip inductor second source.
What should a selector filter on instead?
On the part number stem as well as the four fields, and it should show the code. Take the style code out of the part number, keep it beside the cell, and let the engineer see that a 0.6 nH request in WLCM has three answers with Q 4, 11 and 14. That is how our free cross-reference tool treats these rows: it matches against Walsin’s published catalogue and states every difference from your original rather than hiding it behind a tick.
Paste up to 500 part numbers or drop an Excel or CSV, and read the mismatches before the matches. If your incumbent is from another maker, write down its Q, SRF and DC resistance before you compare, because the four published fields will not pick a Walsin part for you. The unit check on the same file is in inductor part number inductance code, and the construction difference between chip types is in multilayer against wirewound chip inductors. The whole line sits on the Walsin inductor page.
What is physically in Hong Kong is on ready stock: 1,125 part numbers as at 23 September 2026, a dated snapshot and not a live feed. We hold 28 Walsin datasheets, 451 pages, and none covers an inductor, so the code is explained in no document we hold. Ask Walsin, or ask us to put the question on our request list. We are at Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong, (852) 2628 4777. Confirm against both datasheets and qualify in your own circuit.
The short version
The two characters after the size block of a Walsin chip inductor part number take 11 values on 4,119 rows and appear in no export column. 319 of 3,635 cells, 8.8 percent, hold parts that differ in that code and share series, size, inductance and tolerance. They cover 803 parts. In every one of the 319 the minimum Q differs, in 293 the SRF, in 281 the DC resistance and in 231 the rated current. At 6.2 nH in WLCW 2012, one part is Q 50 at 0.11 ohm and 600 mA and the other Q 88 at 35 milliohm and 1.6 A. The Series label does not separate them in three of its labels. This is a field the export left out, not a defect we can show. Qualification stays with you.
Send us the chip inductor lines off your bill of materials and we will return every part in each cell, with the code and the Q beside it. And a question back: when your selector returned one part for 6.2 nH, which of the two did it hide?
Frequently asked questions
What is the two-character code in a Walsin chip inductor part number?
It is the pair after the four-digit size block, such as Z0, HQ, TG or TN. We counted 11 distinct codes on 4,119 rows. No export column carries it, and we hold no Walsin document that defines it, so we do not state what any code stands for.
Why does my 6.2 nanohenry WLCW 2012 search return two parts?
Because WLCW2012Z0J6N2PB and WLCW2012HQJ6N2PB share series, size, inductance and tolerance and differ only in the style code. The first publishes Q 50, 0.11 ohm and 600 milliamp. The second publishes Q 88, 35 milliohm and 1.6 amp.
How many Walsin chip inductor cells hold more than one part?
319 of 3,635 cells, or 8.8 percent, hold parts that differ in the style code while sharing series, size, inductance and tolerance. They cover 803 parts, 19.5 percent of the 4,119 decodable rows. Minimum Q differs in all 319.
Which columns differ between parts in the same cell?
Minimum Q differs in all 319 cells, SRF in 293, DC resistance in 281, rated current in 231 and thickness in 111. In 179 cells the highest Q is at least twice the lowest. Inductance, tolerance, size and series are identical by construction.
Does the Series column separate the parts?
Not in three labels. WLCM Series holds four codes, MCI Series three and WLCW Series two, and 319 cells in those labels return more than one part. MCI-TM holds one code and is unambiguous, and the WCI and WCA series never share a cell.
Does Venatech hold a datasheet that explains the style code?
No. We hold 28 Walsin datasheets, 451 pages, covering 26 MLCC and 2 chip resistor series, and none covers an inductor. Specifications on this line must be confirmed against Walsin’s own site, and the meaning of the code is on our request list.