Ferrite Bead vs Inductor: Reading Walsin’s Impedance (100MHz) Column

In a ferrite bead vs inductor comparison built from Walsin’s own export, only 609 of 5,410
inductor rows (11.3%) publish a real, non-zero figure in the Impedance (100MHz[Ω]) column.
Those 609 cluster in exactly 15 series. The other 4,801 rows — including every part in Walsin’s
four largest inductor series — read a literal 0, because impedance at 100 MHz is a bead
specification, not a power-inductor one, and the column exists for both part types in one shared
schema.

Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the full inductor
parametric export published by Walsin Technology (Walsin) — 5,411 rows, one of which (Test123999) is a QA
test row excluded from every count below. The real total is 5,410 parts. Every part number
named in this post is real and checked against that extract.

What is actually different between a ferrite bead and a chip inductor in Walsin’s data?

The Unit column, not the series name. 4,125 rows report in nH, 644 in µH — these are
inductors, selected by inductance value. 641 rows report in Ω — these are beads, selected by
impedance at a stated frequency. A bead suppresses high-frequency noise; an inductor stores
energy or sets a resonant frequency. Walsin exports both through one ten-column schema with no
separate “type” flag, so Unit is the only reliable discriminator.

How many Walsin inductor parts publish a real 100 MHz impedance figure?

609 of 5,410 — 11.3%. The dedicated Impedance (100MHz[Ω]) column is meant to carry exactly
this figure, and it does, but only for just over one in nine parts. The remaining 4,801 rows
carry a literal 0, not a blank cell — a filter that excludes zero values will silently drop
every row, which looks identical in the data to “measured and found to be zero.”

Which series populate the Impedance column and which leave it at zero?

Fifteen series carry a real figure, fourteen of them on 100% of their rows:

Every other series in the catalogue — including the four largest, WLCW (791 parts), WCI
(720), WCA (622) and WQCW (569) — publishes a literal 0 in this column on every single
row. Those four series alone are 2,702 of the 4,801 zero rows, and they are Walsin’s core
wirewound power inductor lines, not beads, so the zero is expected. It just is not marked as
“not applicable” anywhere in the export.

Does a zero in the Impedance column always mean the part is not a bead?

No, and this is the finding worth checking before you build a filter. 32 part numbers carry
Unit = Ω — meaning Walsin itself classifies them as impedance-rated bead parts — and still
read a literal 0 in the Impedance (100MHz[Ω]) column. All 32 sit in four series: MCM Series
(11), MPA Series (9), HCM Series (7) and WLPN (5). Their real impedance figure is not
missing; it is parked in the Inductance column instead, labelled in Ω:

609 rows with a real figure in the named column, plus these 32 with the real figure in the
wrong column, account for all 641 rows Walsin marks Unit = Ω. The column named for the
measurement is not where the measurement lives for 5% of the bead-type rows.

How do a bead and an inductor compare at the same 0603 case size?

Real parts, same 1608(0603) footprint, opposite jobs:

Same case size, same twelve-column schema, and the two part types answer completely different
questions. A bead’s whole job is stated in the Impedance column; an inductor’s is stated in
Inductance, and Impedance is not a mismatch here — it is simply off-topic for that row.

Which column should I actually filter on to find a ferrite bead?

Unit = Ω, not Impedance (100MHz[Ω]) != 0. The unit column correctly flags all 641 bead-type
rows; the impedance column only confirms the figure for 609 of them and reads zero for the
other 32, which still are beads by Walsin’s own classification. Filtering on impedance alone
would drop those 32 real bead parts from a search entirely.

For how the same inductance figures compare against a tight-tolerance, high-Q subset suited to
RF matching, see inductors for RF matching networks.
For the construction difference behind bead and inductor behaviour, see
multilayer vs wirewound chip inductors. Browse
the Walsin inductor range for the full catalogue.

The short version

A real 100 MHz impedance figure exists on 609 of 5,410 inductor rows, concentrated in 15 bead
and automotive-bead series. Every other series, including Walsin’s four largest, reads zero
there — expected, since they are power or RF inductors, not beads. 32 bead-type rows carry their
real impedance figure in the Inductance column instead, not the one named for it. Filter on
Unit, not on the Impedance column, to find every bead.

Send us your noise-suppression or power requirement and we will shortlist real Walsin bead or
inductor part numbers, checking the right column for each.

Faster than an email. The cross-reference tool takes a pasted list or a spreadsheet and returns Walsin inductor candidates field by field, differences included. Ready stock shows what is physically in Hong Kong, so you can see straight away whether a line is a stock pull or a production slot.

Frequently asked questions