Choosing an RF Chip Filter by Band

Walsin Technology (Walsin) lists 235 LTCC RF chip filters: 112 band pass, 94 low pass,
26 balanced and 3 high pass. Select by band first. The 2.4 GHz group holds 115 parts,
telecom 2G/3G/4G holds 69, 5G Wi-Fi 25 and MoCA/DOCSIS 16. Insertion loss then decides
between them. Two parts carry no band label at all.

Every figure is measured from Venatech’s extract of Walsin’s own LTCC filter data, 235 rows.
A second export, FRESH_rf_filter, holds the same 235 part numbers; never add the two.

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What RF chip filters does Walsin make?

Four topologies in one LTCC series: 112 band pass, 94 low pass, 26 balanced, 3 high pass.
Walsin gives case size in metric code, nine sizes from 605 up to 3225, with 2012 the most
populated at 90 parts. Walsin’s BAW and SAW filters are in separate exports.

Topology	Parts	Case sizes held	Insertion loss range
Band pass filter	112	1005, 1109, 1411, 1608, 2012, 2520, 3225	0.6 dB to 3.9 dB
Low pass filter	94	605, 1005, 1608, 2012, 3225	0.37 dB to 2.5 dB
Balanced filter	26	1510, 1608, 2012, 2520	1.5 dB to 4.5 dB
High pass filter	3	605, 3225	0.6 dB to 2.0 dB

The part-number prefix identifies the topology. RFBPF and RBBPF are band pass, RFLPF
low pass, RFHPF high pass, RFBPB balanced. KFBPF marks a MoCA/DOCSIS band pass part and
AMLPF an automotive low pass part. All 26 balanced parts carry RFBPB.

The four digits after the prefix are usually the case size, but not always. Seventeen of the
235 parts break the pattern: RFBPF2008A13T, RFBPF2009A12T, RBBPF2010A10T and
RFBPF2108AM627Q1C all read 2012 in the Size column despite four different digit groups,
and RFHPF0605040K0T and RFLPF06050G9D0T read 605. Read the Size column.

Which Walsin filter covers 2.4 GHz Bluetooth, Wi-Fi and Zigbee?

The largest group in the range: 115 parts, split 74 band pass, 24 balanced and 17 low pass.
Band pass parts cover 2400 to 2500 MHz across six case sizes — 1005, 1109, 1411, 1608, 2012
and 2520 — at 0.95 dB to 3.5 dB. The low pass parts here are the quietest in the file, from
0.37 dB.

Part number	Topology	Size	Frequency	Insertion loss	Pins	Match / mismatch on a 0.95 dB target
RFBPF1608060AAT	Band pass	1608	2400 to 2500 MHz	0.95 dB	3	Reference — lowest-loss 2.4 GHz band pass held
RBBPF1411060A8T	Band pass	1411	2400 to 2500 MHz	1.0 dB	5-LGA	Band match, smaller body, 0.05 dB worse, 5 pads not 3
RFBPF2012090ART	Band pass	2012	2400 to 2500 MHz	1.0 dB	4	Band match, larger body, 0.05 dB worse, 4 pads
RFBPF1005040A3T	Band pass	1005	2400 to 2500 MHz	1.50 dB max at 25 degrees C	4	Band match, smallest body, 0.55 dB worse

Pad count is not implied by the case size. Inside the same 2012 footprint the 2.4 GHz band pass parts come with 3, 4, 6, 8, 3-LGA and 4-LGA pin descriptions.
Across the file the Pin Description field takes eight values: 4 on 69 parts, 3-LGA on 45,
8 on 37, 6 on 28, 3 on 20, 4-LGA on 16, 5-LGA on 15 and 6-LGA on 5.

RFBPF1005040A3T carries no numeric insertion loss: the field reads “1.50 dB
max. at 25 degrees C” plus a figure at minus 40 to plus 85 degrees C. A numeric sort will not
order rows like it.

Which filter covers 5 GHz Wi-Fi?

25 parts, of which 19 are band pass, split into two passbands: roughly 4900 to 5950 MHz, and
narrower parts at 5150 to 5950 MHz. Insertion loss runs 0.6 dB to 2.2 dB, and the best figures
are in the 1608 case size.

RFBPF1608060K9T is the lowest-loss part in the group at 0.6 dB over 5150 to 5950 MHz, on a
1608 body with a 3-LGA pad arrangement. Widening the passband costs loss: the 4900 to
5950 MHz parts in the same size sit at 0.85 dB to 1.5 dB, and the 2012 parts at 1.5 dB to
2.2 dB. The group also holds RFHPF0605040K0T, the
only 5 GHz high pass part in the file, at 0.60 dB max at 25 degrees C.

What is available above 6 GHz?

Two parts, and they are the rows a naive search will not return. RFBPF20077G2W0T covers
6240 to 8240 MHz at 2 dB on a 2012 body. RFBPF25207G3W1T covers 6230 to 8500 MHz on a 2520
body at 3.9 dB max over 6230 to 7238 MHz. Both are 50 ohm, 4-pad parts; 8500 MHz is the
highest frequency in the file.

Unique to Venatech’s data. Walsin’s filter export spells the same filter type two
ways. “Band Pass Filter” with a double space between “Band” and “Pass” appears on 110
parts; “Band Pass Filter” with a single space appears on 2. An exact string filter on
either spelling silently returns the wrong population. The two single-space rows are
RFBPF20077G2W0T and RFBPF25207G3W1T — and they are also the only two rows in the file
with a blank Application field and a blank Category field, and the two
highest-frequency parts Walsin lists, reaching 8240 MHz and 8500 MHz. The two parts a
string filter drops are precisely the two highest-band parts in the range, and they are
equally invisible to anyone filtering by application or category. None of this is
published; it comes from taking a value-count on Walsin’s own export columns.

A third inconsistency: the same column writes “Low Pass filter” with a lowercase
f on all 94 low pass rows, while “High Pass Filter” and “Balanced Filter” are title case.

Which filter covers the cellular and GNSS bands?

69 parts in the telecom 2G/3G/4G group, 60 of them low pass. The 8 band pass parts are
narrowband: 869 to 894, 925 to 960, 1805 to 1880, 1880 to 2025, 1930 to 1990, 2300 to 2390
and 2490 to 2690 MHz. One GNSS part covers 1558 to 1606 MHz; two automotive low pass parts
form their own group.

Part number	Topology	Size	Frequency	Insertion loss	Impedance	Match / mismatch
RFBPF1109B501T	Band pass	1109	869 to 894 MHz	0.9 dB	50 ohm	Narrowband cellular, 5-LGA
RFBPF1109B201T	Band pass	1109	1930 to 1990 MHz	1.7 dB	50 ohm	Same size and pads, 0.8 dB worse at higher band
RFBPF1411070E0T	Band pass	1411	1558 to 1606 MHz	1.8 dB	50 ohm	GNSS band, different size, 5-LGA
RFLPF1608060F88Q1C	Low pass	1608	10 to 2700 MHz	0.5 dB	50 ohm	Mismatch — wideband low pass, not a band pass
AMLPF16082G5WM0T29	Low pass	1608	2300 to 2690 MHz	0.9 dB	50 ohm	Automotive group, 6 pads not 5-LGA

Insertion loss tracks frequency inside the 1109 band pass family: 0.9 dB on the two sub-1 GHz
parts, 1.4 dB at 1805 to 1880 MHz, 1.7 dB at 1930 to 1990 MHz. Same case size, same pads,
same topology, 0.8 dB between the ends.

The MoCA/DOCSIS group is the outlier on impedance: 16 parts across three topologies,
RFBPF3225180C0T band pass over 1125 to 1675 MHz, RFHPF3225170F0T high pass over 950 to
2150 MHz and RFLPF3225200Q5T low pass over 5 to 1002 MHz. All three are 75 ohm on a 3225
body, at 1.8 dB, 2.0 dB and 1.8 dB.

How do I pick between filters that cover the same band?

Four fields, in this order. The passband. The attenuation profile at the interferer you are
rejecting. The insertion loss. Then case size and pad count, which decide whether it lands on
your board at all.

The attenuation field is the most specific and the most often skipped. Walsin gives it as
minimum decibel figures over named windows chosen per part. RFBPF1411070E0T, the GNSS part,
publishes 30 dB minimum over 824 to 849 MHz, 30 dB minimum over 880 to 915 MHz, 10 dB minimum
over 1880 to 1910 MHz, 22 dB minimum over 1920 to 1980 MHz and 30 dB minimum at 2400 MHz.
Another part on the same passband will not have the same windows.

Insertion loss spreads wider than expected: 0.95 dB to 3.5 dB inside the 2.4 GHz band pass
group alone, a 2.55 dB spread among parts claiming the same passband.

What impedance are Walsin’s RF chip filters?

50 ohm on 195 parts, 75 ohm on 14 and unstated on 26. The 14 at 75 ohm are all MoCA/DOCSIS
parts. The 26 with a blank impedance field are exactly the 26 balanced filters, which use two
separate columns instead.

Impedance field	Parts	Which parts	Match / mismatch
50 ohm	195	All groups except MoCA/DOCSIS	Standard RF match
75 ohm	14	MoCA/DOCSIS only	Mismatch — cable impedance, not 50 ohm
blank	26	All 26 balanced filters	Mismatch — uses the unbalanced and balanced columns

Their Unbalanced Impedance column is 50 ohm on
all 26 parts, but Balanced Impedance is mostly not a number: on 20 of the 26 it is free text
naming a conjugate match to a specific transceiver chipset, with only 6 rows giving 50 or 100.

Why does a search on filter type drop parts?

Because the Filter Type column is not clean. Filter on “Band Pass Filter” and you get 110
parts, missing 2. Filter on “Band Pass Filter” and you get 2, missing 110. Filter on
“Low Pass Filter” in title case and you get zero.

The Frequency column has the same problem in another form: the range separator appears as a
bare tilde, a spaced tilde, a bare hyphen and a spaced hyphen, and some rows omit the space
before “MHz”. Parse on digits, and normalise whitespace and case before counting.

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FAQ

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Next step

Band first, attenuation window second, insertion loss third, footprint fourth. Send the
passband, the interferer to reject and the pad count your layout allows, and Venatech Limited,
an authorised Walsin distributor in Hong Kong, will return the candidate part numbers with
insertion loss and attenuation side by side.

Send your BOM to Venatech · Browse the
Walsin RF range · Read
Walsin RF: balun, filter, coupler, multiplexer
and High-Q low-ESR MLCC for RF.

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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.