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Multilayer vs Wirewound Chip Inductors: Which Construction Do You Need?

A multilayer chip inductor prints a spiral conductor between co-fired ceramic or ferrite
layers. A wirewound chip inductor winds wire onto a core. Multilayer is smaller and more
rugged. Wirewound gives higher Q, higher current and lower DC resistance for the same
inductance. Choose wirewound when Q or current matters, multilayer when size does.

What is the difference between a multilayer and a wirewound chip inductor?

Multilayer construction screen-prints conductive traces onto green ceramic sheets, stacks
them, and co-fires the assembly into a monolithic block. Wirewound construction winds an
insulated conductor around a ferrite or ceramic core and terminates the ends onto plated
caps.

The electrical consequences follow from the conductor. A printed trace is thin and narrow,
so it has more resistance per unit length than drawn wire. More resistance means lower Q and
more self-heating, which caps the current rating. Wire is thicker and lower loss, so
wirewound parts reach higher Q and carry more current at the same inductance.

Multilayer wins everywhere else. There is no wire to break and no winding to shift under
vibration, and it reaches the smallest case sizes, where winding wire stops being practical.

Walsin Technology (Walsin) lists 5,411 inductors across 47 series in our catalogue extract.

Which construction do I need for an RF matching network?

Whichever gives you the Q you need at your operating frequency, with a self-resonant
frequency comfortably above it. Q sets insertion loss; SRF sets the usable band. As a
working rule, keep the operating frequency below a third of the SRF, and treat Q below about
20 as a real loss contributor in a narrowband match.

Here are eight real Walsin parts from our extract, spanning two case sizes and six series.
The right-hand column states field by field what matches and what does not.

Walsin part number	Series	Case size	Inductance	Tolerance	Q min	SRF (min)	RDC	Rated current	Match / mismatch vs WLCW1005Z0J1N0TB
WLCW1005Z0J1N0TB	WLCW Series	1005 (0402)	1.0 nH	±5%	16	12.7	0.045 Ω	1.36 A	reference part
WCI1005CP1N0B	WCI Series	1005 (0402)	1.0 nH	±0.1 nH	16	12.7	0.045 Ω	1360 mA	match: case size, inductance, Q min, SRF, RDC, current · mismatch: different series, tolerance stated as ±0.1 nH absolute rather than ±5% relative, current stated in mA
WCA1005CP1N0B	WCA Series	1005 (0402)	1.0 nH	±0.1 nH	16	12.7	0.045 Ω	1360 mA	match: case size, inductance, Q min, SRF, RDC, current · mismatch: different series, absolute tolerance, current unit
WQCW1005Z0J1N0TB	WQCW Series	1005 (0402)	1.0 nH	±5%	16	12.7	0.045 Ω	1.36 A	match: case size, inductance, tolerance, Q min, SRF, RDC, current — every parametric field · mismatch: series designation only
WLCW1005Z0J1N8TB	WLCW Series	1005 (0402)	1.8 nH	±5%	16	12.0	0.07 Ω	1.04 A	match: series, case size, tolerance, Q min · mismatch: 1.8 nH, SRF 12.0 not 12.7, RDC 56% higher, 1.04 A not 1.36 A
WCI1005CP1N2B	WCI Series	1005 (0402)	1.2 nH	±0.1 nH	16	12.9	0.09 Ω	740 mA	match: case size, Q min · mismatch: 1.2 nH, absolute tolerance, SRF 12.9, RDC twice the reference, current down 46%
WLCM0603Z0B0N3TB	WLCM Series	0603 (0201)	0.3 nH	±0.1 nH	4	10000.0	0.07 Ω	850 mA	match: nothing beyond the Sn-terminated chip format · mismatch: 0603 (0201) case, 0.3 nH, absolute tolerance, Q min 4 not 16, SRF stated as 10000.0, RDC 56% higher, 850 mA
MCI0603HQ0N3BHBP	MCI Series	0603 (0201)	0.3 nH	±0.1 nH	4	10000.0	0.07 Ω	850 mA	match: every parametric field with WLCM0603Z0B0N3TB · mismatch vs reference: case size, inductance, tolerance form, Q min, SRF figure, RDC, current

Two patterns matter more than any single row. The Q collapse at 0201 is severe — Q min
falls from 16 at 1005 (0402) to 4 at 0603 (0201). In a narrowband match at 2.4 GHz, a Q of 4
puts real insertion loss in the signal path, and no amount of careful layout recovers it.
RDC and rated current move together, inversely — the 1.0 nH part is 0.045 Ω and 1.36 A,
the 1.2 nH part 0.09 Ω and 740 mA. Doubling the DC resistance roughly halves the current
rating, because the limit is self-heating and heating goes as I²R.

Which construction do I need for a DC-DC converter output?

Wirewound or a power-specific multilayer, and the decision is made by DC resistance and
saturation current rather than by Q. A converter inductor carries continuous load current
plus ripple. Losses are I²R in the winding plus core loss. A 0.045 Ω part at 1 A dissipates
45 mW; a 0.09 Ω part at the same current dissipates 90 mW.

Saturation is the harder constraint, and it is not the rated current. Rated current in a
parametric table is usually a thermal limit. Saturation current is where permeability falls
and inductance drops, often by 30%. A converter running at saturation loses its inductance
exactly when load current peaks, and ripple current runs away.

How do I read Q, SRF and DC resistance together?

They describe one physical reality from three directions. DC resistance is the conductor
loss at zero frequency. Q is the ratio of reactance to total loss at a stated frequency. SRF
is where the winding’s own parasitic capacitance resonates with its inductance, above which
the part is a capacitor. Low RDC tends to give high Q; compact geometry tends to give low
SRF. No construction optimises all three.

For an RF part, read in this order: SRF against your highest frequency of interest, because
a part above its SRF is the wrong component; then Q at your operating frequency, not at the
frequency the datasheet chose; then RDC and current. For a power part, reverse it.

Which Walsin inductor series covers my case size?

The catalogue is deepest at 1005 (0402) with 1,092 parts, then 1608 (0603) at 962, 0603
(0201) at 888 and 2012 (0805) at 883. 2520 (1008) holds 664 and 3225 (1210) holds 291.
Everything above that is specialist, below 110 parts a size.

By series, the largest lines are WLCW at 792 parts, WCI at 720, WCA at 622, WQCW at 569,
WLCM at 559 and MCI at 501 — six series accounting for 3,763 of 5,411 parts. The other 41
series split the rest, many under 30 parts.

The 208 inductors with no datasheet at all

This is the finding worth carrying away. 208 parts in Walsin’s inductor range have no
datasheet — not a broken link, not a superseded document, none. They sit in the VEFL, WIP,
SCM, SCA and BIH series.

That is a sourcing problem, not a cosmetic one. A part with parametric data and no datasheet
cannot be qualified. You cannot check the saturation curve, the temperature rise curve, the
land pattern or the test conditions behind the Q figure.

If a part from any of those series appears on a BOM you have inherited, ask for the
datasheet before assuming it can be re-qualified. Venatech Limited, an authorised Walsin
distributor in Hong Kong, holds the parametric data for all of them and can request
documentation from Walsin directly.

Walsin’s product index is at https://www.passivecomponent.com/products/ — the product
index page, not a direct link to any datasheet PDF.

Why does the parametric data not say which construction a part uses?

Because Walsin’s inductor export has no construction field. It carries series, size,
inductance, tolerance, Q min, SRF, RDC and rated current, and nothing stating multilayer or
wirewound. Construction has to be read from the series datasheet, which is why this article
compares measured behaviour rather than labelling series by type.

Frequently asked questions

Is a wirewound chip inductor always higher Q than a multilayer one?

Usually, at the same inductance and case size, because drawn wire has lower loss than a printed trace. It is not universal — Q depends on frequency, core material and geometry as well as conductor type. Compare the Q figure at your actual operating frequency rather than assuming the construction decides it.

Why is Q so low on 0201 chip inductors?

Because there is very little conductor in the body. Walsin’s 0603 (0201) parts in Venatech’s extract specify Q min of 4, against 16 for the 1005 (0402) parts. The smaller part has less conductor cross-section and shorter turns, so the ratio of reactance to loss falls. It is a geometry limit, not a manufacturing shortfall.

Is rated current the same as saturation current?

No, and conflating them causes converter failures. Rated current in a parametric table is usually a thermal limit based on a specified temperature rise. Saturation current is where inductance collapses as the core saturates. Both appear on the datasheet; only one appears in the export. Check both.

Which Walsin inductor series have no datasheet?

VEFL, WIP, SCM, SCA and BIH — 208 parts in total have no datasheet at all. Parametric data exists for them, but there is no document behind it, which means no saturation curve, no temperature rise curve and no land pattern. Treat them as not selectable until Walsin supplies documentation.

Can I substitute a multilayer inductor for a wirewound one in a matching network?

Only after comparing Q at your frequency, SRF and tolerance field by field. Matching the inductance value is the easy part. A multilayer part with lower Q will raise insertion loss and broaden the match, and a lower SRF may put your operating frequency in the wrong region entirely.

Next step

Send us the inductance, the frequency, the Q you need and the current the part has to carry.
We will return the Walsin candidates with series, case size, inductance, tolerance, Q min,
SRF, DC resistance and rated current stated field by field — and we will tell you which have
a datasheet behind the numbers. We will not tell you a part is equivalent. We will show you
exactly where it differs.

Send us your BOM → ·
Browse Walsin chip inductors →

Cross it yourself. The cross-reference tool takes a single part number or a whole BOM column and returns the Walsin candidates with every field that differs stated plainly — qualification stays with you. Ready stock shows what is held in Hong Kong today, with an RFQ against any line.