One-chip FM transmitter solution
MS-BOSS wrote 04/27/2020 at 09:39 • 0 pointsHi,
has anyone ever been building FM transmitter using some one-chip solution? I was able to find the Si47xx transmitters, however they are NRND and cost about $15 each. Then there was the RDA5280 which can be bought for $2, however lacks RDS and is no longer manufactured. And the last option I found was the KT0803 (especially its L variant which has highest SNR) which is still manufactured, costs about $0.5, however doesn't have RDS compatibility.
Does anyone know of any other all-in-one chip which would include PLL, DSP core and mixers in one package? If possible, then also with RDS capability.
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Great research, thanks for sharing! I almost wanna bookmark this in case my future self wants to build an "FM transmitter using some one-chip solution", it's such a hassle to dig thought obscure chinesse sources and docs!
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Thanks, originally this was meant as a way to ease my research, however I ended up having to find out myself since it seems no one ever replies to Stack questions :D
The problem isn't Chinese docs. The real PITA is obtaining at least a snippet of them.
There are many other chips which I omitted, because of their age (that usually implies no RDS support), however if you do not need RDS, then even something like BH1415 could be sufficient. Look at the Facebook link - some of these older chips are listed over there.
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Well, as it looks like, there is a good transmitter QN8027 made by Quintec Corporation. It is easy to get them from Aliexpress and they are cheap, however the company seems to be either gone or have gone "non-public" like many other chinese corporations. So, it is unclear whether the company works, whether the chip is still made and so on. However, the datasheet looks western-world-grade. And it can do RDS! There is even an appnote with reference design and info about how to build a power amplifier on its output.
There are even some measurements of boards with this chip:
https://karusisemus.wordpress.com/2019/08/17/chinese-lcd-fm-transmitters-based-on-qn8027-chip/
https://goughlui.com/2016/09/27/review-tested-generic-usb-fm-transmitter-fm_mic_v5-0-9/
There are even some implementations of the I2C control:
http://bascomavr.3bb.ru/viewtopic.php?id=1135
https://github.com/dragon-engineer/QN8027
A similar chip is the QN8007 which apparently can do RDS, too. It has a long and comprehensive datasheet in English. Its input is both I2S and analog. This one looks really good, its specs are better than the QN8027. It can be obtained on AliExpress.
https://wenku.baidu.com/view/900798f80242a8956bece429.html
https://github.com/gabriel-tenma-white/qn8007_fm_tx
QN8036 is a full-fledged transceiver. Can be obtained on AliExpress.
https://www.facebook.com/2312112109062823/posts/quintic-qn8066-great-fm-transmitter-ic-digital-fm-transceiver-for-portable-devic/2410107039263329/
https://github.com/freedombird/fmradio?fbclid=IwAR2mjugsMq-_Lqn-nDNKuZfVZbkA-RJRxPxYEyALGQt5LQvszPFA-O0ceYo
http://en.pudn.com/Download/item/id/2591570.html?fbclid=IwAR3huJ519mDzSFZBI0PQUwhBCaHAaFrdUpMWJEliKTKuN2xZoFPMwsgsMnA
https://darkliferadio.proboards.com/thread/779/fm-transmitter-ics-review-question?fbclid=IwAR3rK0f1uDlFU77HXi-5GJj6W1tkimN87py2VERufYVqF4o1TVx_Q_kt6yg
Also, I found SX6510 and BX8610. The SX6510 is similar to the KT0803, but in smaller package. The other one - I couldn't get its datasheet. It was difficult to get a datasheet even of the SX6510. It seems there are many other FM transmitters, however getting their datasheets is... well, difficult. SX6520 could be similar to SX6510, the offers for ordering seem to imply no differences. SX6530 is in QFN package, otherwise probably similar.
Then there is AS6001/AS6002. These have datasheets, but do not look interesting.
AS6300 has no obtainable datasheet.
HS6760 has Chinese appnote. It can be used without MCU as it allows several default frequencies to be set by a voltage on SDA. Interesting, but still yuck.
HX8089 has reference schematic. On some shops it is marked as FM receiver and on some as FM transmitter. (that is not impossible since the RDA5280 used to do both).
HS6760 seems to have some Chinese datasheet and maybe even support for RDS. https://wenku.baidu.com/view/abb7252911a6f524ccbff121dd36a32d7375c7de.html?re=view
AH1035/1036/1037 seem to be basic transmitter with no RDS support.
SX710 and SX750 have no info available.
GS2229 has simple English datasheet. It looks almost the same as KT0803. I wonder if most of these chips have the same die inside and just different "manufacturers".
THG4649 was licensed by FCC. It has two variants, one for CCIR, one for OIRT. It seems to be in some professional-grade-looking Chinese electronics. No datasheet found.
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