Teseo-LIV3F vs STA8089FG why the module is shielded and the IC is unshielded?

[jg_spitfire]

Hi, I have been reading about this module (Teseo-LIV3F) and this IC (STA8089FG), as I can see both offers almost the same characteristics and both need external circuits to connect an antenna, so in which case should I use one or another?, why the module is shielded and the IC is unshielded?, I thought that all the RF components must be shielded but this is a case where I think I was wrong

Thanks

[Tesla DeLorean]

With the IC you're expected to design the board and provide shielding. You need to pay attention to your supplies, and routing clocks and GPIO away from the IC.

The IC generates local copies of code/carrier, and then correlates over several milli-seconds, the GNSS signals are buried in the noise floor. It is going to have some sensitivity to switching noise in the IF of the baseband processing, similar signals will look like jammers. Given you're generating a lot of frequencies internally, you don't want to be radiating those either.

Unless you're doing 100K+ units I don't suppose ST is going to support you in an IC-Down implementation.

[Francesco Virlinzi · Accepted solution]

Added to what Clive already said you have also to take into account that:

• STA8089FG isn't a final product; it's just a chip which needs extra components to be used. Due to that ST doesn't care on legal certification to stay on the market (these certification have to be managed by the final producer)
• Teseo-LIV3F is a final product ready to be used. with just a battery and it works... due to that it has to follow mandatory European and USA certification (ETSI and FCC) to stay on the market. To follow this certification shield is mandatory.

At the end....

If you use Teseo-LIV3F certification are already managed by ST, while if you use STA8089FG you will have to manage shield and certification on your own.

Hope this helps

Regards

Francesco

[jg_spitfire]

Hi, I have read about the shield and certification and I understand that, but as I mentioned before both needs external components, so the unique difference would be the certification right?, the 7.1 schematic is a photo from the TESEO module hardware manual, even it seems that TESEO needs more external components than the STA8089 (figure 30), because it mentions that you need an external SAW filter and LNA, and the STA8089 has internal LNA and does not mention any time that a SAW is needed, just needs a few components for the antenna detection, or maybe am I wrong?, thanks

[jg_spitfire]

Hi, it makes sense (shield the IC), but look at this https://www.mikroe.com/gnss-zoe-click, if shielding is a requirement why do they put that GNSS module (U1) unshielded? , is very strange, someone told me that they do this to make a cheap product and also said that with the appropiate PCB design you can avoid the EMI, what do you think about this click board?

[Francesco Virlinzi]

Hi Jairo

Teseo-LIV3F is a product ready for Mass-Market. It has reduced pin-out and we can support it also in case of low volumt.

STA8089FG is a chip which wants high valume to be supported.

Regards

Francesco

[STLearner]

Hi Francesco,

Would like to check if the Teseo-LIV3F has certification for Australia/New Zealand market?

Thank you.