Hi,

This seems like a strange issue. If the issue did not exist when the device is placed outside the enclosure, I would say that probably the nIRQ trace is behaving as an antenna due to wrong PCB layout design. Can you confirm that the issue does not appear without the enclosure?

Can you share photos of the measurement setup? Also, it might make sense to share the schematic and layout of the design. If it is confidential, I can create a Salesforce case of this forum topic.

Daniel

Hi Oscar,

If there is no via on the pad, 25% is a good void criteria. BLE112 even has the castellated edges so inspecting the joint should be easy.

Daniel

Hi Oscar,

If there is no via on the pad, 25% is a good void criteria. BLE112 even has the castellated edges so inspecting the joint should be easy.

Daniel

Hi Drauzio,

We do not have tested solution for 100ohm matching for 915MHz, but we can run some simulations on that. Note that the matching network can be single-ended or differential, moreover the topology can be split TX/RX or direct-tie (TX and RX tied together). These are important parameters that are needed before running any simulations.

Daniel

Hi Drauzio,

We do not have tested solution for 100ohm matching for 915MHz, but we can run some simulations on that. Note that the matching network can be single-ended or differential, moreover the topology can be split TX/RX or direct-tie (TX and RX tied together). These are important parameters that are needed before running any simulations.

Daniel

Hi James,

The matching network values you are referring to in 4455-PCE10D868 are optimized for an RF stick board named 4455-LED-868. It contains only a 3-element harmonic filter stage (5.1pF-6.8nH-5.1pF) which is enough in that specific application with the given antenna.

However, if a different antenna is used, it cannot be guaranteed that the 3-element filter stage will be enough for regulatory compliance, therefore a safe solution can be to use the values from the AN693 application note.

Note that there can be slightly different component value recommendations based on the inductor type in the matching network (multilayer, wirewound).

Daniel

Hi James,

The matching network values you are referring to in 4455-PCE10D868 are optimized for an RF stick board named 4455-LED-868. It contains only a 3-element harmonic filter stage (5.1pF-6.8nH-5.1pF) which is enough in that specific application with the given antenna.

However, if a different antenna is used, it cannot be guaranteed that the 3-element filter stage will be enough, therefore a safe solution can be to use the values from the AN693 application note.

Note that there can be slightly different component value recommendations based on the inductor type in the matching network (multilayer, wirewound).

Daniel

Hi James,

The matching network values you are referring to in 4455-PCE10D868 are optimized for an RF stick board named 4455-LED-868. It contains only a 3-element harmonic filter stage (5.1pF-6.8nH-5.1pF) which is enough in that specific application with the given antenna.

However, if a different antenna is used, it cannot be guaranteed that the 3-element filter stage will be enough, therefore a safe solution can be to use the values from the AN693 application note.

Note that there can be slightly different component value recommendations based on the inductor type in the matching network (multilayer, wirewound).

Daniel

Hi Kalyani,

AN427 has details on Si443x RX LNA matching procedure:

https://www.silabs.com/documents/public/application-notes/AN427.pdf

You can find RLNA and CLNA values in Table 1, calculated matching network element values are shown in Table 2 and Table 4.

Table 3 shows bench-tuned component values, however 403MHz is not included there. For 403MHz operation, you can use the values calculated for 400MHz as a starting point.

Daniel

Hi Kalyani,

AN427 has details on Si443x RX LNA matching procedure:

https://www.silabs.com/documents/public/application-notes/AN427.pdf

You can find RLNA and CLNA values in Table 1, calculated matching network element values are shown in Table 2 and Table 4.

Table 3 shows bench-tuned component values, however 403MHz is not included there. For 403MHz operation, you can use the values calculated for 400MHz as a starting point.

Daniel