RF Balun Band Code in the Part Number, Austria: 28 of 72 Walsin Baluns Spell a Centre Frequency, 4 Sit Outside Their Printed Range, and a 2.4 GHz Code Search Finds 25 of 39

Walsin balun part numbers hint at a band but cannot be searched on it. We decoded all 72: 28 spell a centre frequency, 4 of those sitting outside the printed range, and 44 carry one letter. A 2.4 GHz letter search finds 25 of the 39 baluns whose printed range contains the band.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the Walsin Technology (Walsin) balun export, Walsin_Balun.xlsx: 72 rows, every part number unique. We hold no Walsin datasheet for any RF part, so this post is arithmetic on that one .xlsx file and nothing else. The question is the one a layout engineer in Vienna or Graz asks when a 2.4 GHz or sub-GHz radio needs a balun and the part number looks as if it already answers it. Every part number below is real. We re-measured every count ourselves.

Can I read a Walsin balun’s band from its part number?

For 28 of 72 baluns you can read a figure, and for the other 44 you can read a letter. The 28 spell the figure as digit, G, digit and one letter, such as 1G8D or 2G5W. The 44 carry one band letter after a three-digit group, such as the A in RFBLN1608050AGT. We split every part number in Walsin_Balun.xlsx after the BLN and the four-digit size code. No row failed to parse, so 28 plus 44 is 72.

The reading of the figure as gigahertz is ours. Walsin prints no key for it. 1G8D reads as 1.8 GHz, 2G5W as 2.5 GHz, 0G9D as 0.9 GHz and 3G6W as 3.6 GHz, and the printed Frequency column supports that on most rows. The rest of this post tests how far.

Does the centre frequency in the code sit inside the printed range?

On 24 of 28 rows, yes. On 4 it does not, and on every one the miss is 5 or 6 MHz. The two 0G9D parts with a printed range of 824~894 MHz sit 6 MHz below the 900 MHz the code implies, and the two 1G8D parts at 1805~1990 MHz start 5 MHz above 1800. We computed the distance from the decoded figure to the nearest edge of the range Walsin’s published export prints, on all 28.

Code	Parts	Distinct printed ranges (MHz)	Range widths (MHz)	Code figure inside the range	Match / mismatch
0G9D	8	5: 699~960, 729~960, 824~894, 860~960, 880~960	70 to 261	6 of 8	Mismatch — RFBLN16080G9D3T and RFBLN20120G9D0T read 824~894, 6 MHz short of 900
1G8D	5	3: 1700~2000, 1710~1880, 1805~1990	170 to 300	3 of 5	Mismatch — RFBLN06051G8DM1T69 and AMBLN06051G8DM1T69 start at 1805, 5 MHz above 1800
1G9D	3	2: 1805~2170, 1850~2020	170 to 365	3 of 3	Match — one code, two ranges
2G5W	10	2: 2300~2690, 2300~2700	390 to 400	10 of 10	Match — all ten, but see the next section
3G6W	1	1: 3550~3700	150	1 of 1	Match — RBBLN16083G6W0T
5G5W	1	1: 3000~8000	5,000	1 of 1	Match, but 5,000 MHz wide — RFBLN20125G5W0T

We have not seen this counted anywhere: the same four-character code names different bands. The eight 0G9D parts cover five printed ranges, from a 70 MHz window to a 261 MHz one, and the widest starts at 699 MHz. The code is a family label. It is not a coverage statement.

What do the single-letter band codes tell you?

Less than the figure codes. We grouped the 44 letter-coded parts by their letter and counted the distinct printed ranges and the distinct Application labels. Letter A covers 25 parts, 24 at 2400~2500 MHz and one at 2300~2500 MHz, and carries three different Application labels. Letters B, C and E each appear once.

Letter	Parts	Distinct printed ranges (MHz)	Distinct Application labels	Example part	Match / mismatch
A	25	2: 2400~2500, 2300~2500	3: 2.4GHz BT/WiFi/Zigbee, Telecom (2G/3G/4G), Automotive	RFBLN1608050AGT	Mismatch — one letter, three application labels
K	8	3: 4900~5875, 4900~5900, 4900~5950	1: 5G WiFi	RFBLN1005040K1T	Match on label, three range ends
Y	4	4: 703~821, 703~894, 717~821, 729~821	1: Telecom	RFBLN1005040Y1T	Mismatch — four ranges for four parts
F	4	3: 1800~2700, 1805~2170, 673~2700	1: Telecom	RFBLN1608070F48Q1C	Mismatch — 673~2700 against 1805~2170
B, C, E	1 each	1 each	1 each	AMBLN2012090B1T	Single parts, nothing to compare

The K letter is the tidy one: eight parts, all labelled 5G WiFi, all inside 4900 to 5950 MHz. A is tidy on the range and untidy on the label. The F letter hides a band wider than the band beside it: two parts, RFBLN1608070F48Q1C and RFBLN1608070F58Q1C, read 673~2700 MHz, a 2,027 MHz window.

How many 2.4 GHz baluns does a code search miss?

Fourteen of 39. We counted every balun in Walsin_Balun.xlsx whose printed Frequency range contains all of 2400 to 2500 MHz and compared three ways a buyer might ask. The Application label finds 23, the band letter A finds 25, and the range test finds 39. The 14 parts the letter misses are ten 2G5W parts, one E part and three F parts.

How the search is asked	Parts found	Share of the 39	Example miss	Match / mismatch
Application = 2.4GHz BT/WiFi/Zigbee	23	59.0%	RFBLN2012090AGT (labelled Telecom)	Mismatch — 16 parts missed
Part number letter A	25	64.1%	RFBLN10052G5W3T	Mismatch — 14 parts missed
Printed range contains 2400 to 2500 MHz	39	100%	none	Match — the reference count

The ten 2G5W parts print 2300~2690 or 2300~2700 MHz. They contain the whole 2.4 GHz band and none carries the letter A. Containing the band is not the same as being tuned for it, and a wide-range part can carry more loss at 2.4 GHz than a narrow one, so every miss still needs its published insertion loss read before use.

The same test on the 880 to 960 MHz band gives 9 parts by range and 8 by 0G9D code. Only 6 of those 8 overlap: the two 824~894 MHz parts do not. Three parts that cover the band carry other codes: RFBLN1608070F48Q1C, RFBLN1608070F58Q1C and AMBLN2012090B1T. Code search returns the wrong two and misses the right three.

Does a band code also fix the balanced impedance?

No. We read the balanced-impedance column of Walsin’s published export under each code. Letter A holds six different balanced-side entries across 25 parts: 50 on 13, 100 on 8, 35 on one, and three text entries naming a chipset. The 0G9D parts split 6 at 100 and 2 at 50, and 2G5W splits 9 at 100 and 1 at 50.

Code	Parts	Balanced-side entries	Insertion loss range (dB)	Example part	Match / mismatch
A	25	50 (13), 100 (8), 35 (1), text (3)	0.55 to 2.0	RFBLN1608050AGT at 50	Mismatch — a 2.4 GHz label does not fix the load
0G9D	8	100 (6), 50 (2)	0.85 to 1.3	RFBLN10050G9D0T at 100	Mismatch — 2 of 8 are a 50 to 50 part
2G5W	10	100 (9), 50 (1)	0.55 to 1.2	RFBLN10052G5W3T at 100	Mismatch — one 50 to 50 part
K	8	100 (4), 50 (4)	0.55 to 1.2	RFBLN1005040K1T at 50	Mismatch — an even split

A band code selects a neighbourhood. The balanced side, the case size and the pin count still have to match your transceiver. Our post on the four-port pin gap sets out which of those the export leaves unstated, and how to pick a Walsin RF balun covers the fields in order.

How should an Austrian design search for a balun by band?

By the printed Frequency range, not by the part number. State the lowest and highest frequency your radio needs, keep every balun whose range contains both, then read balanced impedance, case size and insertion loss. That ordering returns the 39 parts for 2.4 GHz where the code returns 25 and the label returns 23. For a sub-GHz design the same rule returns 9 parts at 880 to 960 MHz where the 0G9D code returns 8 and gets two wrong.

Treat the code as a hint for the human reader. It is stable enough to guess a family on a BOM line and not stable enough to drive a filter. Our post on reading an RF filter part number by band reaches the same caution for filters, and this one shows it holds for baluns on a separate count.

The Walsin datasheet for each family is the final authority; Walsin’s own catalogue lists the families, and the RF range page lists the families. Our free cross-reference tool takes a competitor balun and returns the Walsin parts with the differences stated, not hidden, and ready stock shows what is held in Hong Kong as at 23 September 2026. Qualification stays with you: confirm against Walsin’s datasheet when you have it, and qualify in your own circuit.

The short version

Twenty-eight of 72 Walsin baluns spell a centre frequency in the part number; 24 sit inside the printed range and 4 miss by 5 or 6 MHz. The other 44 carry a single letter, and A alone spans three application labels and six balanced-side entries. A 2.4 GHz search finds 23 parts by label, 25 by letter and 39 by range. Search on the printed range, then read the rest.

Send us the balun on your BOM and we will return the Walsin parts whose printed range contains your band, with balanced impedance and case size beside each. And a question back: when your team shortlists RF parts, is the part number or the frequency column the filter?

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Frequently asked questions

<!– wp:rank-math/faq-block {"questions":[{"id":"faq-question-01","title":"Can I read a Walsin balun's band from its part number?","content":"Roughly. Twenty-eight of 72 baluns spell a figure such as 1G8D or 2G5W, and 44 carry a single band letter. The code is not defined in any document we hold, so treat it as a hint and read the printed Frequency column.”,”visible”:true},{“id”:”faq-question-02″,”title”:”Does the centre frequency in the code sit inside the printed range?”,”content”:”On 24 of 28 rows. The four misses are two 1G8D parts starting at 1805 MHz and two 0G9D parts ending at 894 MHz, each 5 or 6 MHz from the code figure. The code is a rounded label, not a coverage limit.”,”visible”:true},{“id”:”faq-question-03″,”title”:”Does the letter A mean a 2.4 GHz balun?”,”content”:”Mostly. Of 25 parts with the letter A, 24 print 2400~2500 MHz and one prints 2300~2500 MHz. The letter carries three different application labels and six balanced-side entries, so it does not choose a part by itself.”,”visible”:true},{“id”:”faq-question-04″,”title”:”How many 2.4 GHz baluns does a code search miss?”,”content”:”Fourteen of 39. The letter A finds 25 parts and the application label finds 23, while 39 print a range containing 2400 to 2500 MHz. The misses include ten 2G5W parts at 2300~2690 or 2300~2700 MHz.”,”visible”:true},{“id”:”faq-question-05″,”title”:”Does the same band code mean the same balanced impedance?”,”content”:”No. The 25 letter A parts hold 50 ohm on 13, 100 ohm on 8, 35 ohm on one and three text entries. The 0G9D parts split 6 at 100 ohm and 2 at 50 ohm. Read the balanced column for every candidate.”,”visible”:true},{“id”:”faq-question-06″,”title”:”Where do I get the meaning of the balun part number?”,”content”:”From Walsin, in writing. We hold no datasheet for any RF part, 457 parts in all, and the code key is on our request list. Meanwhile search the printed Frequency range and qualify the part in your own circuit.”,”visible”:true}],”listStyle”:””,”titleWrapper”:”h3″,”titleCssClasses”:””,”contentCssClasses”:””,”sizeSlug”:””} –>

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