Questions on the S2-LP transceiver

[enrico239955]

Posted on June 20, 2017 at 11:26

Hello,

we are designing an RF interface for the ISM 868-870 MHz band.

We are attracted to the S2-LP transceiver mainly because it drains only 10 mA at 10 dBm RF output power

I got a couple of questions about the S2-LP transceiver.

1. Does it support a TCXO?

If yes, what's the suggested frequency for the best phase noise performance?

2. Does a single chip 'balun + conjugate match + harmonic filter' exist or at least planned for introduction by Q4 2017?

Best Regards,

Enrico Miglore

#balf #conjugate-match #harmonic-filter #tcxo #s2-lp

[matteo239955]

Posted on December 04, 2017 at 12:01

Hello,

I would like to push up the request of Mr. Enrico Migliore which I'm interested in too...

I'm testing the S2-LP transceiver and I'm very excited about performances and power consumption.

I'd like to test the S2-LP in the 868 band-870 MHz with a high precision TCXO to run test in ultra-narrow band (less than 5kHz) using low datarates (down to 600 or 300bps).

Does someone have a piece of schematic to post or a suggested part number?

Thanks and best regards,

Matteo

[Silas Valera]

Posted on December 06, 2017 at 17:42

Hi 

Yes, ST does have a balun that can be used with S2-LP - here is the 

http://www.st.com/en/emi-filtering-and-signal-conditioning/balf-spi2-01d3.html

. Here is the link for the balun data sheet (

http://www.st.com/content/ccc/resource/technical/document/datasheet/group3/e9/ff/cd/1e/4f/dd/49/b4/DM00417488/files/DM00417488.pdf/jcr:content/translations/en.DM00417488.pdf

), also the data sheet contains the suggested schematic. I am actually working on the PCB design using this balun and will test soon. Very excited about this S2-LP + balun.

I have also posted another question about chip antenna to be used with this design.. anyone have any experience regarding the chip antenna, please let us hear your feedback.. 

Best regards

Silas 

[Silas Valera]

Posted on December 16, 2017 at 01:38

Hi Mat,

To your question regarding using S2LP with external TCXO,  you can check this application note (

http://www.st.com/content/ccc/resource/technical/document/application_note/fb/c3/32/7f/4e/a2/4a/d4/DM00086780.pdf/files/DM00086780.pdf/jcr:content/translations/en.DM00086780.pdf

) which is for SPIRIT1 tuned for 169MHz. This SPIRIT1 daughter board uses TCXO which is enabled/disabled by the host controller (just to manage the power conusumption of TCXO), and it specifically talks about narrow band (channel bandwidth <= 25KHz), shows some measurements for frequncy deviation 2.4KHz and 1.2KHz - hope that will be of interest to you.  I believe S2LP is better performing SPIRIT1, the app note can be extended to S2LP. For S2LP, a GPIO can be configured to control external TCXO (see pg 74 of S2LP datasheet). 

I would sure be interested if you run some tests with TCXO connected to S2LP..

Best regards

Silas