Case# 00184890 has been updated. [ref:_00Db0000000YtG6._5003W00000QWgmZ:ref]

[vincent.rizzo]

Hello, 

I provide in BOLD my comments identified by tag 08/08/2023 VFA reply included in the following mail received on 07/08/2023 from my colleague Giuseppe Calcagno.

Could you please provide the reply from your colleague from the HW team?

Best Regards

Vincent

Da: noreply@salesforce.com <noreply@salesforce.com> Per conto di online.support@st.com
Inviato: lunedì 7 agosto 2023 14:55
A: GIUSEPPE CALCAGNO, Vodafone <giuseppe.calcagno@vodafone.com>
Oggetto: Case# 00184890 has been updated. [ref:_00Db0000000YtG6._5003W00000QWgmZ:ref]

*** CASE UPDATE NOTIFICATION ***

Dear Giuseppe Calcagno,
Below case has been updated.

Case#: 00184890
Subject: very hight noise on rx signal received
Description:
Hello,

My colleague from the HW team reviewed the schematics in attachment (RF TRANSCEIVER 4800.pdf). And there are some remarks:
"
We have indeed several remarks that need to be implemented to improve RF results. Comments are based on our 433MHz ref design IKD002V3D whose design files can be found here : STEVAL-IKR002V3D - SPIRIT1 - Low Data Rate Transceiver - 433 MHz - DAUGHTER BOARD - STMicroelectronics)

1- A 330pF capacitor is mandatory in parallel to C103 (Vreg pin) to ensure proper VCO locking.

08/08/2023 VFA reply: ok. Capacitor = 330pF in parallel to C103 added.

2- TX pin is biased at the same time using SMPS_EXT2 pin and Vaux (= Vbatt). This is not recommended and only one configuration should be implemented.
a. By choosing SMPS_EXT2 (normal mode), you can output up to 11.5dbm
b. By choosing Vaux (boost mode), you can output up to 16dBm with a 3v6 Vbatt.
c. What is the configuration you want to use ?

08/08/2023 VFA reply: the HW schematic shared is a Master schematic in which different HW versions are foreseen. At this stage we’ve not frozen which configuration will be used.

From the datasheet we have understood that:

1. if the Normal mode will be implemented: L15 = 100nH and L16 = Not Mounted
2. if the Boos mode will be implemented: L15 = Not Mounted and L16 = 100nH (with Vbatt = 3V, because we don’t have a reference to 3v6 on the PCB).

3- That being said, I recommend referring to the design files of our reference board for proper component value in both RX and TX paths; It looks like the values you implemented are the ones for 868MHz operations not 433MHz operations.
a. For example, we recommend using L21 = open @ 433MHz, while it is set at 22nH in your schematics as onour 868MHz ref design
b. For example, we recommend using L14 = 100nH @ 433MHz while it is set at 27nH in your schematics
08/08/2023 VFA reply: in our application we have two operating modes. RX @433MHz (from driver card) and TX @868MHz (to wireless siren).

I confirm that the values in the schematic are selected from the “Table 3. BOM for different bands” of the datasheet attached.

In particular:

1. the filter/adapter network connected from the pin TX to ANTENNA1 has been selected from the column “868 MHz band2 of Table 3.
2. the filter/adapter network connected from the pin ANTENNA1 to RX_p and RX_n pins has been selected from the column “433 MHz band” of Table 3. (L21 will be Not Mounted)

Can you please confirm that the above considerations are correct and that transmission and reception on different bands can be implemented? Can you please suggest a dedicated filter/adapter network?

A second option that we would like to test is RX @433MHz and TX&RX @868MHz with the same filter/adapter network. Can you please confirm that the 3 bands operation can be implemented and if can you suggest a dedicated filter/adapter network?

Thanks for sending us updated schematics (as well as gerber files) whenever available
"

I have also received the confirmation that your parcel with the key fob is on track. I should get it in a few days so. Meanwhile I am checking the specific case of OOK reception in Direct GPIO mode.

Thanks & Regards,
Raphael

Please visit ST Customer Support Portal for further information.
Link to access the case:
https://ols.st.com/s/case/5003W00000QWgmZQAT

Best regards,
ST Customer Support

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