The 21 Walsin Inductor Series With Fewer Than 20 Parts Each

21 of Walsin Technology (Walsin)’s 47 inductor series hold fewer than 20 part numbers each. Together they are 240 of the 5,410 real inductor rows — 4.4% of the line across 45% of its series names. Four of those 21 publish byte-for-byte identical parametric data under four different series names. Knowing which series are thin changes how you second-source.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds Walsin’s inductor parametric export — 5,411 rows, of which 5,410 are real parts. This post is written from it. Every part number below is real. Counts are of part numbers, not pieces. Venatech holds no Walsin inductor datasheet PDF at all, so every specification figure here is read from the export and should be confirmed against Walsin’s own published datasheet before design-in.

How many Walsin inductor series are small, and how small?

Twenty-one series hold fewer than 20 part numbers. The count runs from 19 down to 4.

Series	Part numbers	Case sizes	Selection values published
WLPH(HC)	19	2016, 2520	9 inductances, 0.1–4.7 µH
WIP_S	19	2016, 2520	9 inductances, 0.1–4.7 µH
SCA	18	2012	15 impedances, 67–750 Ω
SCM	18	2012	15 impedances, 67–750 Ω
WQCF	18	2012	15 impedances, 67–750 Ω
WTCF	18	2012	15 impedances, 67–750 Ω
MCB-H	17	0402, 0603, 0805	10 impedances, 20–1000 Ω
MIP	13	0805, 0806, 1008	7 inductances, 0.47–6.8 µH
BIH	13	2012	2 impedances, 50 and 75 Ω
MCM	11	1012, 2012, 3216	6 impedances, 67–220 Ω
MHC-P	11	0603	10 impedances, 22–600 Ω
WTBL	10	2012	2 impedances, 50 and 75 Ω
MPA	9	0805, 0806, 1008	5 inductances, 1.0–4.7 µH
WIP_A	8	3225	8 inductances, 0.47–6.8 µH
MIP-P	8	0603, 0805	5 inductances, 0.24–2.2 µH
HCM	7	1012, 2012	5 impedances, 15–120 Ω
MAP	6	0603	6 inductances, 0.24–2.2 µH
WLPN	5	2.0 × 2.0 mm	5 inductances, 1.0–4.7 µH
MIP-H	4	0603, 0805	2 inductances, 2.2 and 4.7 µH
MCB-B	4	0402	4 impedances, 600–1800 Ω
WIP_Y	4	2012, 2016	2 inductances, 0.47 and 1.0 µH

The other 26 series carry the remaining 5,170 parts, and four of them — WLCW (791), WCI (720), WCA (622) and WQCW (569) — account for half the line on their own. The comparison of the two largest wirewound families is in Multilayer vs wirewound chip inductors.

Which four series publish the same data under four names?

SCA, SCM, WQCF and WTCF. Each holds exactly 18 part numbers, all at 2012 (0805), and the four datasets are identical row for row.

We aligned the four series by impedance and compared all eleven parametric fields — size, length × width, thickness, inductance, impedance at 100 MHz, unit, tolerance, minimum Q, minimum SRF, DC resistance, rated current and saturation current. That is 594 cell comparisons against SCA as the baseline. Exactly one cell differs.

Impedance at 100 MHz	SCA part	SCM part	WQCF part	WTCF part	Match / mismatch
67 Ω	SCA2012FS670M	SCM2012FS670M	WQCF2012Z0M670PB	WTCF2012Z0M670PB	Match on all 11 fields
220 Ω	SCA2012FS221M	SCM2012FS221M	WQCF2012Z0M221PB	WTCF2012Z0M221PB	Match on all 11 fields
750 Ω	SCA2012FS751M 220 mA	SCM2012FS751M 220 mA	WQCF2012Z0M751PB 220 mA	WTCF2012Z0M751PB 240 mA	Mismatch — rated current, 1 cell of 594

Every one of the 72 parts is 2.0 × 1.2 mm, 1.2 mm thick and ±20%. The 15 FS or Z0M parts step 67, 75, 90, 100, 120, 160, 180, 200, 220, 260, 360, 370, 430, 600 and 750 Ω; the three FH or FHM parts repeat 67, 90 and 120 Ω under a different internal code.

Practically, that means these four series names are four routes to the same selection table, and WTCF2012Z0M751PB is the one part in the group with a rated current that is not matched by its three namesakes. If you have standardised on one of the four and want a second internal part number, the other three give you an identical published specification.

How much real choice does a small series give you?

Less than the part count suggests, on four of the 21. BIH and WTBL publish 13 and 10 part numbers but only two impedance values each, 50 Ω and 75 Ω — the remaining part numbers are packaging and internal-code variants of the same two electrical options. MIP-H has four part numbers and two inductances, 2.2 µH and 4.7 µH. WIP_Y has four part numbers and two inductances, 0.47 µH and 1.0 µH.

Series	Part numbers	Distinct electrical values	Match / mismatch against part count
BIH	13	2	Mismatch — 13 codes, 2 choices
WTBL	10	2	Mismatch — 10 codes, 2 choices
MIP-H	4	2	Mismatch — 4 codes, 2 choices
WIP_Y	4	2	Mismatch — 4 codes, 2 choices
MCB-B	4	4	Match — every code is a distinct value
MAP	6	6	Match — every code is a distinct value
SCA	18	15	3 codes repeat an existing value

Nine of the 21 series publish five or fewer distinct electrical values each — 64 part numbers that look like choice and are not. If your design needs a value those series do not carry, you have to change series, and usually case size with it.

Are the small series beads or inductors?

Thirteen of the 21 are beads, by the Unit = Ω tag. But the column the value lives in is not consistent, and on two series the tag itself looks wrong.

Series	Unit tag	Value actually published in	Our reading
SCA, SCM, WQCF, WTCF, MCB-H, MHC-P, BIH, WTBL, MCB-B	Ω	Impedance at 100 MHz column	Bead, correctly filed
MCM, HCM	Ω	Inductance column; impedance column reads 0	Bead, impedance in the wrong column
MPA, WLPN	Ω	Inductance column; impedance column reads 0	Microhenry inductor, wrongly tagged Ω
WLPH(HC), WIP_S, WIP_A, WIP_Y, MIP, MIP-P, MIP-H, MAP	µH	Inductance column	Inductor, correctly filed

The last two rows matter. MCM1012B670F06BP carries 670 in its part number and a value of 67 — that is 67 Ω, a bead impedance sitting in the inductance column. But MPA25201R0MBE carries 1R0 and a value of 1.0, at 1,600 mA rated current with 55 mΩ of DC resistance. A 1 Ω bead does not come with a 1.6 A rating and 55 mΩ of DC resistance; a 1 µH power inductor does. WLPN202012M4R7PB reads 4R7 and 4.7, at 1 A and 241 mΩ, the same way.

So of the 32 long-tail parts whose electrical value sits in the wrong column, 18 (MCM and HCM) are beads and 14 (MPA and WLPN) are microhenry inductors tagged as beads. A parametric search that trusts the Unit column puts all 32 in the wrong bucket.

All 609 bead rows in the export, long tail included, also read a literal 0 in Q Min and SRF(min) rather than being left blank. Zero is a value, not an absence, so a filter for a minimum Q keeps them and a sort on SRF puts them first.

Which small series have no datasheet?

Three of the 21, plus the three WIP sub-series. SCM (18 parts), SCA (18) and BIH (13) are among the 208 Walsin inductor part numbers with no datasheet at all, together with WIP, VEFL and the WIP_S (19), WIP_A (8) and WIP_Y (4) sub-series in this list.

That is 80 of the 240 long-tail part numbers with no published datasheet — a third of the long tail, against 3.8% of the line as a whole. The thin series are disproportionately the undocumented ones. For those, the export row is the only specification in existence as far as anything Venatech holds is concerned, and the export row is exactly what the sections above show to be unreliable on column placement and unit tagging.

Rated current is the figure most often misread on these parts. What it does and does not tell you is in Rated current vs saturation current in chip inductors. None of the 240 long-tail parts publishes a saturation current except the four MIP-H rows. The full range is on the Walsin inductor range page.

Why do these series break a part-number search?

Three reasons, all measurable.

Hyphens. 326 of the 5,410 inductor part numbers contain a hyphen, across 10 series. Four of those are in this list — WIP_S, WIP_A, WIP_Y and BIH — and in all four, every part number is hyphenated. A BOM search or a part-number regex that treats a hyphen as a separator splits those 44 codes in two and matches neither half.

Two notations for one package. Five physical packages appear in the Size column written two ways — bare metric (2012) and metric with imperial in brackets (2012(0805)). 141 rows use the bare form and 1,930 the bracketed form for those same five packages. Inside this list the split runs straight through the four identical series: SCA and SCM write 2012(0805), WQCF and WTCF write 2012. A string filter on either form returns two of the four series and misses the other two.

Package	Rows written bare	Rows written as metric(imperial)
2012	47	883
2016	32	20
2520	52	664
3216	2	72
3225	8	291
Total	141	1,930

WLPN is worse again: its five rows write the size as 2.0*2.0, a decimal dimension pair. It is one of 17 rows in the export that do this.

Series names that do not match their own convention. Five series names in the export are malformed. AIP Seires misspells “Series” on 71 parts. WIP_A Series and WIP_Y Series carry a double space. MCI-TM (172 parts) and WLPN (5) have no “Series” suffix at all. Filtering the export on the string “Series” silently drops 177 real parts; filtering on “AIP Series” drops 71.

The short version

Twenty-one of Walsin’s 47 inductor series are smaller than 20 part numbers, and they hold 4.4% of the line. Check three things before you design one in. Is the series one of SCA, SCM, WQCF or WTCF, where four names publish one dataset and only WTCF2012Z0M751PB differs? Does the series publish more electrical values than part numbers would suggest — BIH and WTBL have 23 codes between them and four choices? And does a datasheet exist, because a third of the long tail has none.

Thin is not the same as bad. MCB1005B601FBP is a 600 Ω bead at 0402 in a four-part series, and if it is the right part it is the right part. It simply has no neighbour to move to.

Send us the inductance or impedance, the case size and the current and we will tell you which series carry it, how deep each one is, and whether a datasheet exists. Or give us one part number and ask us to cross it.

Two things you can do without waiting for a reply. Cross your part — paste a single number or drop in an Excel or CSV of the whole line, and each result names what matches and what does not. And ready stock lists the inductor part numbers held in Hong Kong, with an RFQ against any of them.

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Frequently asked questions

<!– wp:rank-math/faq-block {"questions":[{"id":"faq-question-01","title":"How many inductor series does Walsin publish?","content":"Forty-seven, across 5,410 real part numbers in Walsin's parametric export. The count excludes Test123999, a QA test row that is live in Walsin’s production export with free text in a numeric column. Twenty-one of the 47 series hold fewer than 20 part numbers each, totalling 240 parts.”,”visible”:true},{“id”:”faq-question-02″,”title”:”Which Walsin inductor series are smallest?”,”content”:”MIP-H, MCB-B and WIP_Y hold four part numbers each, and WLPN holds five. MIP-H and WIP_Y publish only two distinct inductance values apiece, so four part numbers buy two electrical choices. MCB-B is the one four-part series where every code is a distinct value, at 600, 1000, 1500 and 1800 Ω.”,”visible”:true},{“id”:”faq-question-03″,”title”:”Do SCA, SCM, WQCF and WTCF inductors differ from each other?”,”content”:”Not in anything Walsin publishes parametrically. All four hold 18 part numbers at 2012, and across 594 cell comparisons of eleven fields exactly one differs: WTCF2012Z0M751PB is rated 240 mA where SCA2012FS751M, SCM2012FS751M and WQCF2012Z0M751PB read 220 mA at the same 750 Ω. Venatech has flagged this for confirmation.”,”visible”:true},{“id”:”faq-question-04″,”title”:”Why does a Walsin inductor part number search miss parts?”,”content”:”Three measured reasons. 326 part numbers contain a hyphen, which splits them in a BOM search. Five packages are written both as 2012 and as 2012(0805) in the same Size column, 141 rows against 1,930. And five series names are malformed, so a filter on the word \”Series\” drops 177 real parts.”,”visible”:true},{“id”:”faq-question-05″,”title”:”Which Walsin inductor series have no datasheet?”,”content”:”VEFL, WIP, SCM, SCA and BIH — 208 part numbers in total — have no datasheet in anything Venatech holds, and Venatech holds no Walsin inductor datasheet PDF at all. Eighty of the 240 long-tail part numbers fall in that group, which is a third of the long tail against 3.8% of the line.”,”visible”:true},{“id”:”faq-question-06″,”title”:”Is a small Walsin inductor series a supply risk?”,”content”:”A small series gives you no adjacent part to move to if your value changes, and on four of the 21 it gives fewer electrical choices than part numbers. That is a design-margin question rather than a supply one. Ask for the datasheet and the current lead time on the specific part number before the design is frozen; Venatech will request both.”,”visible”:true},{“id”:”faq-question-07″,”title”:”Are the Ω-tagged Walsin inductor series all ferrite beads?”,”content”:”No. Thirteen of the 21 long-tail series are tagged Unit = Ω, but MPA and WLPN carry nRn inductance codes, rated currents of 1 A and above and DC resistances in the tens of milliohms, which reads as microhenry power inductors rather than beads. Fourteen parts are affected. Venatech has flagged it for confirmation with Walsin.”,”visible”:true}],”listStyle”:””,”titleWrapper”:”h3″,”titleCssClasses”:””,”contentCssClasses”:””,”sizeSlug”:””} –>

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Three ways to get this answered today

1. Cross a part, free. Paste up to 500 part numbers, or drop an Excel or CSV file, into the free cross-reference tool. It is matched against Walsin’s published catalogue and returns candidates field by field, with every difference from your original stated rather than hidden. Filter by commercial or automotive grade, or for soft termination, high temperature, safety certified, high Q / low ESR or low profile. There is no login and no charge.

2. Send the whole BOM. Upload a BOM and request a quote and we will come back line by line — including the lines we cannot help with, which is usually the more useful half of the answer.

3. Check the shelf before you commit. Ready stock shows what was physically in Hong Kong as at 23 September 2026. It is a dated snapshot, never a live feed, and quantities are never permanent.

Why take our word for any of this? Don’t — check it.

Venatech Limited (威納電子有限公司) is an authorised Walsin Technology distributor in Hong Kong. Confirm that with Walsin rather than with us. On the safety capacitor series we hold UL file E182369, which is searchable in UL’s own public database, together with TUV certificates R50381780 and R50195920 and CQC CQC20001280137 and CQC20001280136, against EN 60384-14:2023, IEC 60384-14:2023 and UL 60384-14. We hold 28 Walsin datasheets, 451 pages, and we will send the one covering your part number. Shipments arrive in original sealed Walsin packaging with lot and date-code traceability, and a certificate of conformity is available per shipment on request.

We will also tell you what we do not hold, which no competitor publishes. REACH, SVHC, conflict minerals, PFAS, China RoHS, ISO 9001, IATF 16949, PPAP, IMDS and a Declaration of Conformity appear nowhere in those 451 pages. You would rather hear that from us now than from your own supplier-approval team later. AEC-Q200 is compliant in Walsin’s own words and never certified, we hold no manufacturer’s end-of-life or allocation list for any brand, and qualification in your own circuit stays with you. We will not tell you a part is equivalent. We will show you where it differs.

Venatech Limited · Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong · (852) 2628 4777 · Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation.