Hi Sheela,

In order to understand the issue better could you please clarify the questions below?

1. Is the testing conducted or radiated?

2. If radiated, what is the distance between the TX and RX devices?

3. What is the radio type used on the TX side?

4. Have you repeated the test with an Si4356 based Evaluation Board as well? If so, do you see similar issues with that HW?

Daniel

Hi Suhitha,

Figure 12 is concentrating on the GND size next to the module and not showing the real ground keepout dimensions. The white ground keepout area should follow the drawing of Figure 2 in the BT121 datasheet.

Daniel

Hi,

The absolute maximum rating on VREG_ENA is 4.9V. On the reference design diodes are added to drop the voltage to 4V.

Daniel

Hi,

The absolute maximum rating on VREG_ENA is 4.9V. On the reference design diodes are added to drop the voltage to 4V.

Daniel

Hi,

The white area is where no copper or components should be placed. Components can be placed on the GND plane (green area), just make sure that there is at least 1 PCB layer which is full GND plane with no traces or components on it. This can be one of the inner layers as well.

Daniel

Hi Ryosuke,

Figure 12 in the BT121 datasheet answers your question:

https://www.silabs.com/documents/public/data-sheets/BT121-Datasheet.pdf

With 10mm GND approximately 90% of the maximum range is expected.

Daniel

Hi,

The white area is where no copper or components should be placed. Components can be placed on the GND plane (green area), just make sure that there is at least 1 PCB layer which is full GND plane with no traces or components on it. This can be one of the inner layers as well.

Daniel

Hi,

For reference I copy here a short summary of the discussion on this case on Salesforce that might be the root cause of the issue:

1. Not proper matching network. The recommended matching network component values can be found in Table 14 in AN627.

2. Missing GND vias under the Si4467 chip. AN629 page 6 bullet 2 describes the need for the exposed pad vias.

3. The TX current consumption strongly depends on the termination impedance. Antenna impedance should be checked or the Si4467 matching should be terminated by wideband 50ohm (e.g. spectrum analyzer).

4. Max power setting is used (0x4F), which might result higher than 13dBm output power. Power level should be adjusted while measuring output power on a spectrum analyzer until 13dBm is achieved.

Daniel

Hi,

For reference I copy here a short summary of the discussion on this case on Salesforce that might be the root cause of the issue:

1. Not proper matching network. The recommended matching network component values can be found in Table 14 in AN627.

2. Missing GND vias under the Si4467 chip. AN629 page 6 bullet 2 describes the need for the exposed pad vias.

3. The TX current consumption strongly depends on the termination impedance. Antenna impedance should be checked or the Si4467 matching should be terminated by wideband 50ohm (e.g. spectrum analyzer).

4. Max power setting is used (0x4F), which might result higher than 13dBm output power. Power level should be adjusted while measuring output power on a spectrum analyzer until 13dBm is achieved.

Daniel