Inductor Size Column for Poland: 40 Strings, and a Bracketed Filter Drops 275 of 518 Parts Rated 2 A or More

The Walsin inductor size column holds 40 different strings, not 10 case sizes, and no series spells its size two ways. For an engineer in Poland, a filter on the ten bracketed codes returns 4,997 of 5,410 real rows and silently drops 275 of the 518 parts rated 2 A or more.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the inductor parametric export published by Walsin Technology (Walsin): 5,410 real rows once the QA test row Test123999 is excluded. This post is written from the Size, Size L*W (mm), Series and Rated Current columns of that file, read as raw strings. Every part number below is real. We hold no Walsin datasheet for any inductor, so every figure is export-sourced, and the question is one a buyer in Poland meets the moment a case-size filter is switched on: which parts did it leave out?

How many different strings does the Walsin inductor Size column hold?

Forty, in three spelling conventions. We parsed all 5,410 rows and counted every distinct string in the Size column. Ten strings are a four-digit code with the imperial code in brackets, such as 2520(1008); fifteen are a bare four-digit code such as 2520; and fifteen are millimetre dimensions such as 2.972*2.134. The ten bracketed strings carry 4,997 rows, the bare strings 388 and the dimension strings 25.

Spelling convention	Distinct strings	Rows	Series using it	Median rated current	Example string	Match / mismatch against a filter written for the bracketed form
Four digits plus bracketed imperial code	10	4,997	31	500 mA	1608(0603)	reference
Bare four-digit code	15	388	14	3,000 mA	2520	Mismatch — same kind of code, no brackets, zero hits
Millimetre dimensions in the Size field	15	25	2	2,900 mA	2.972*2.134	Mismatch — not a case code at all

We have not seen this counted anywhere. The export names 47 distinct series once spacing is normalised, and 47 is also the sum of the series counts above: zero series appear under more than one convention. The spelling in the Size column is a property of the series, not of the part.

Which series hide behind each kind of size string?

Mostly the power families sit outside the brackets. We grouped the 413 rows that do not use the bracketed form by series. Ten of the 14 bare-code series are power or large-body families, and the two dimension-string series, WQQC and WLPN, together hold 25 rows. The other four, HCM, MCM, WQCF and WTCF, are small-body parts at the bare 1012, 2012 and 3216 codes. The table lists the larger groups; WIP_A, WIP_Y, HCM, MCM and WLPN make up the remaining 35 rows.

Series	Rows outside the bracketed form	Size strings used	Rated current range, mA	Match / mismatch against a filter on 2520(1008)
CSME	89	4040, 5050, 6060	200 to 6,000	Mismatch — no brackets
AIP	71	4442, 5452, 5754, 7066, 7265	1,200 to 30,000	Mismatch — the series name is spelled “Seires” in the export
CSMEA	53	4040, 5050, 6060	200 to 4,900	Mismatch — no brackets
VEFL	27	5754, 7165	3,500 to 19,200	Mismatch — no brackets
WIP, WLPH, WIP_S, WLPH(HC)	82	2016, 2520	1,300 to 6,000	Mismatch — the same footprint as the bracketed 2520 parts, without the brackets
WQQC	20	14 dimension strings	2,700 to 4,400	Mismatch — the size field holds the body dimensions
WQCF, WTCF	36	2012	220 to 400	Mismatch — small-body parts, bare code

We counted the series column as a raw string too. AIP Seires is the export’s own spelling, and WIP_Y Series carries a double space, so a filter on the word “Series” drops some of these rows before the size is even read. For how to tell the families apart, see how to tell the Walsin inductor series apart.

What does a bracketed-size filter lose in rated current?

More than half of the high-current parts. We converted the Rated Current column to milliamps on all 5,410 rows, reading the 71 unit-less cells as milliamps as our earlier power-inductor post did. A filter on the ten bracketed strings drops 328 of the 1,148 parts rated 1 A or more, 28.6 percent, and 275 of the 518 rated 2 A or more, 53.1 percent.

Rated current threshold	All parts at or above it	In bracketed strings	Outside the brackets	Share a bracketed filter drops	Match / mismatch against a “show me the power parts” request
1 A or more	1,148	820	328	28.6%	Mismatch — more than a quarter missing
2 A or more	518	243	275	53.1%	Mismatch — more than half missing
3 A or more	367	162	205	55.9%	Mismatch — more than half missing
5 A or more	192	93	99	51.6%	Mismatch — more than half missing

The filter loses 7.6 percent of the file and just over half of the high-current parts. That is the reverse of what a case-size filter is for. The usual reading of Rated Current and what it leaves out is in rated current versus saturation current in chip inductors; only 146 of 5,410 rows publish a saturation current at all.

Does the same case code behave differently with and without brackets?

Yes, at five codes, and the two spellings hold different populations. We compared every code that exists both ways. The bare forms hold 141 rows from 5 series at 2520, 2012, 2016, 3216 and 3225; 94 of those 141 are rated 1 A or more, against 398 of the 1,930 rows in the bracketed forms of the same five codes.

Code	Bare rows	Bare series	Bare median, mA	Bracketed rows	Bracketed series	Bracketed median, mA	Match / mismatch
2520	52	4	3,200	664	9	600	Mismatch — the bare form is the high-current family
2012	47	5	330	883	21	400	Mismatch on series; medians within 70 mA
2016	32	5	3,400	20	4	2,800	Mismatch — two lists for one footprint
3216	2	1	500	72	6	1,000	Mismatch — two rows only
3225	8	1	3,200	291	10	600	Mismatch — the bare form is the high-current family

The pattern is the finding. The bracketed 2520(1008) rows are mostly signal inductors of 600 mA median, while the bare 2520 rows are the 1,360 to 5,900 mA power parts. The footprint is the same code, and a buyer who picks either spelling sees half the picture. That five codes are written both ways has been published before; which parts sit on which side has not. For the case-size convention itself, see case sizes, imperial and metric.

What should a Poland-based buyer filter on instead of the Size column?

On the measured footprint and the rated current, not the string. The Size L*W (mm) column carries a value on every row, and we checked that it parses on all but the 19 rows where 3.2&1.6 holds an ampersand. Six real parts show how the strings, footprints and ratings sit together.

Part number	Series	Size string	Size L*W (mm)	Inductance	Rated current	Your incumbent part	Match / mismatch
WLCW2520Z0J8N2PB	WLCW	2520(1008)	2.92*2.79	8.2 nH	1 A	___	Match on code, mismatch on measured body: 2.922.79 against 2.52.0
MPA25201R0MBE	MPA	2520(1008)	2.5*2.0	1 (unit field reads Ω)	1,600 mA	___	Match on code and body, mismatch on series family
WLPH252010MR22PP	WLPH	2520	2.5*2.0	0.22 uH	5.9 A	___	Match on body with the row above, mismatch on string and on rated current
WIP322512A-R47ML	WIP_A	3225	3.2*2.5	0.47 uH	5.8 A	___	Mismatch — bare 3225, not returned by 3225(1210)
WQQC0908Z0J25NPB	WQQC	2.972*2.134	2.972*2.134	25 nH	4.4 A	___	Mismatch — the string is the body dimension
AIP0615MB-R47M	AIP	7066	7.0*6.6	0.47 uH	10 A	___	Mismatch — a four-digit code that is not an EIA case size

Three rules follow. Match on Size L*W (mm) first and on the string second. Filter Rated Current after converting both units. And never treat a four-digit code as a case size until you have seen its body dimensions. Our free cross-reference tool keeps the original string beside any normalised value, so a difference shows rather than hides. The inductor range sits on the inductor page, and what is 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

Walsin’s inductor Size column holds 40 strings in three conventions: 10 bracketed, 15 bare, 15 dimensions. We counted 47 series and zero use more than one convention. A filter on the ten bracketed strings returns 4,997 of 5,410 rows and drops 275 of the 518 parts rated 2 A or more, 53.1 percent. At the five codes written both ways, the bare forms are the high-current families. Match on the measured footprint, convert the current unit, and confirm every figure against Walsin’s own site because we hold no inductor datasheet. We will not tell you a part matches on size. We will show you the string the file holds. Qualification stays with you.

Send us the inductor line from your Polish BOM with the size filter you used, and we will tell you which rows it excluded. And a question back: when your selector found no 2520 power inductor, did you conclude none exists?

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Frequently asked questions

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