RF Balun Selection: Zero of Walsin’s 72 Baluns Say Which Pin Is Which

RF balun selection on Walsin’s own data comes down to a four-port device collapsed into one field: of 72 real baluns, zero rows in the Pin Description column name which pin carries the unbalanced signal, which two carry the balanced pair, or which are ground — every row states only a bare pin count.

Frequency, impedance ratio, insertion loss and balance all transfer cleanly. The one field a four-port part actually needs does not.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds Walsin Technology (Walsin)’s whole RF parametric data folder, including Walsin_Balun.xlsx and its twin FRESH_rf_balun.xlsx. We opened both files and compared every one of the 72 part numbers and every field between them: byte for byte identical. Every part number below is real and came out of that file. We hold no RF datasheet of any kind — not one of our 28 Walsin PDFs covers the RF line — so every specification below is the export’s own value, stated as such.

How many real RF baluns does Walsin publish, and is the file doubled?

72, not 144. We counted both files row by row: Walsin_Balun.xlsx and FRESH_rf_balun.xlsx each hold 72 rows, the same 72 part numbers in the same order, with identical values in all 12 columns. The same pairing repeats across the whole RF folder — balun, coupler, multiplexer, antenna switch, SAW and BAW filter each ship twice under two filenames — so the deduplicated RF catalogue is 457 part numbers, not the 914 you get by summing every file in the folder once each.

Series	Rows	Sizes present	Applications present
Balun	72	1608 (24), 1005 (23), 2012 (19), 605 (6)	Telecom 2G/3G/4G (32), 2.4GHz BT/WiFi/Zigbee (23), 5G WiFi (8), Automotive (6), others (1), 5G (1), blank (1)

What does a four-port balun selection actually need, field by field?

Seven fields, and Walsin’s export fills six of them cleanly. A balun is not a two-terminal part: it has one unbalanced port, two balanced ports and at least one ground reference, and a real selection has to confirm impedance, frequency, loss and balance on all of them, plus which physical pin is which. We checked population on all 72 rows across every column in the file.

Field a balun selection needs	Column in Walsin_Balun.xlsx	Rows populated	Transfers to a selection?
Unbalanced port impedance	Unbalanced Impedance (Ω)	72 / 72	Yes — fixed 50Ω throughout
Balanced port impedance / ratio	Balanced Impedance (Ω)	72 / 72	Mostly — 69 numeric, 3 name a chipset instead of a ratio
Frequency range	Frequency	72 / 72	Yes, across 29 distinct band strings
Insertion loss	Insertion Loss (dB)	72 / 72	Yes
Balance — phase	Phase Difference	72 / 72	Yes, but spelled with three different degree characters (already established — see below)
Balance — amplitude	Amplitude Difference (dB)	72 / 72	Yes, but format is inconsistent: 68 rows state a bare number, 4 spell out “0 ± X”
Which pin is which of the four ports	Pin Description	72 / 72 populated	No — see next section

Six of seven fields a buyer actually needs are usable straight out of the export. The seventh is populated on every row and answers nothing.

Does the Pin Description column ever say which pin is which port?

No. Not once in 72 rows. We read every value in the Pin Description column, expecting a pin-by-pin map of unbalanced, balanced-plus, balanced-minus and ground. What is actually there is a bare integer — 42 rows say 6, 25 say 4, 1 says 10 — and 4 rows say 4-LGA, which glues the pin count to a package code rather than adding function. Zero of the 72 rows name which physical pad carries the unbalanced signal, which two carry the balanced differential pair, or which are ground. We have not seen this counted anywhere.

Pin Description value	Rows	What it actually tells you
6	42	A count. Not which 6.
4	25	A count. Not which 4.
4-LGA	4	A count plus a package code. Still not which 4.
10	1	A count. Not which 10.

That matters because a 4-pin and a 6-pin balun do not necessarily split the same way — a 4-pin part may ground the case rather than bring out a separate ground pin, and a 6-pin part may add two extra ground or mounting pads rather than a second control line. Without a pin-by-pin map, a layout built from the count alone is a guess at which pad is hot.

Which Walsin balun fits a 2.4 GHz, 1608, 100 ohm balanced requirement — and where does the data run out?

Eleven of the 72 baluns are 1608-size parts tagged for the 2.4 GHz BT/WiFi/Zigbee application. We filtered all 72 rows to that size and application and checked each one against a stated requirement: 2400–2500 MHz, 50Ω unbalanced, 100Ω balanced, insertion loss at or under 1.2 dB, 6-pin package.

Part number	Insertion loss	Balanced impedance	Phase balance	Pins	Match / mismatch vs the stated requirement
RFBLN1608070ADT	1.0 dB	100Ω	180° ± 10°	6	Match on every published field — but the pin map is still not stated
RGBLN1608070A57B1U	1.2 dB	100Ω	180° ± 10°	6	Match at the boundary of the loss requirement — pin map not stated
RGBLN1608070A5T	1.2 dB	100Ω	180° ± 10°	6	Match at the boundary of the loss requirement — pin map not stated
RGBLN1608070A1T	1.5 dB	100Ω	180° ± 15°	6	Mismatch — exceeds the 1.2 dB ceiling and the tighter phase tolerance
RFBLN1608060ACT	2.0 dB	Conjugate match to Nordic nRF24LE1	160° ± 15°	6	Mismatch — no resistive 100Ω figure to check, loss exceeds ceiling, and the nominal phase is 160°, not 180°
RFBLN1608050AM0T63	1.0 dB	50Ω	180° ± 10°	6	Mismatch — half the required balanced impedance

Three of the eleven clear every published field. None of the eleven, matching or not, states which of its 6 pins is the unbalanced terminal, which two are balanced, or which are ground — that question sits outside the export on all three candidates equally.

Does the balance data, phase and amplitude, transfer cleanly?

Mostly, with one spelling defect already on file. Phase balance is written as 180° ± tolerance on every row, but Venatech’s house data notes already establish that the degree sign is not one character — U+00B0 on 51 rows, U+02DA on 5, and the Greek-letter lookalike U+2218 on 16 — so a text match on the ASCII degree sign alone misses 21 of the 72 rows. Amplitude balance carries a smaller version of the same problem: 68 rows state a bare figure such as 2 or 2.5, meaning “0 dB ± that figure,” while 4 rows spell the zero out explicitly as 0 ± 2 or 0 ± 2.5. Both conventions mean the same thing; only one of them says so.

Does Venatech hold a Walsin RF balun datasheet?

No. We hold 28 Walsin datasheets, 451 pages, covering 26 MLCC series and 2 chip resistor series. We checked the RF folder in _Walsin_Datasheets against all 28 filenames: none covers a balun, coupler, multiplexer or antenna switch. Everything in this post is the parametric export’s own value, including the pin counts, and none of it has been checked against a manufacturer datasheet because we do not hold one for this line. Power handling, return loss and the actual pinout are not in the export and cannot be confirmed from our side — ask us for the series datasheet and your request is what puts it on the list to Walsin.

What should an engineer do before committing to a balun’s pinout?

Treat the Pin Description figure as a pin count, never a pin map, and get the layout confirmed before the board is released. A four-port part with an unconfirmed pinout is a rework risk no matter how well the impedance and frequency match.

1. Fix the balanced-side impedance and frequency band first — those are the two fields the export states cleanly on all 72 rows.
2. Treat the pin count as a constraint, not a layout. A 6-pin or 4-pin figure tells you how many pads to route, not which pad is which. Request the datasheet or the land pattern drawing before committing copper.
3. Cross the whole BOM in one pass at the free cross-reference tool — paste up to 500 part numbers or drop an Excel or CSV, and it matches against 800,000+ crossable Walsin part numbers, decoding 18 manufacturers’ part numbers and stating every difference from your original rather than hiding it.
4. Check what is physically in Hong Kong on ready stock, a dated snapshot as at 23 September 2026, before you commit a production slot to any size or band.

For the full RF range, see Walsin RF baluns, filters, couplers and multiplexers and The Walsin RF front end: switches, BAW, SAW and multiplexers. The full line is on the Walsin RF products page.

The short version

Walsin’s balun export is complete on six of the seven fields a four-port selection needs: unbalanced impedance, balanced impedance, frequency, insertion loss, and phase and amplitude balance all transfer, with one known spelling split in the degree character. The seventh field, Pin Description, is populated on all 72 rows and names a pin count on every one of them — never a pin. We have not seen that counted anywhere else.

Send us the balun candidates off your BOM with your chip’s balanced-side impedance and frequency band, and we will come back with every real Walsin part that matches field by field — then tell you plainly that the pinout still needs the datasheet, not the export, before you release a board. Qualification stays with you.

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Frequently asked questions

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