ESP8685 LNA_IN Impedance

[axe111]

Hi there,

in the Datasheet of ESP8685 the impedance of LNA_IN pin is not listed.
In ESP32-C3 Datasheet also no value is given.

Please advise on which value to use for ESP8685H4 chip.

Thank you!

[ESP_Minatel]

Hi,

Please take a look at the ESP32-C3 Hardware Design Guidelines page.

The RF trace should have a 50 Ω characteristic impedance.

[axe111]

Hi,

thank you. The Trace to the Antenna should be 50Ω single ended impedance.
Matching circuit is intended for matching LNA_IN pins output impedance to the trace and later to the antenna.

However Hardware design guide and Datasheet do not mention the ouput impedance of LNA_IN pin, so this is what i am looking for.

In addition I think there is an error in https://docs.espressif.com/projects/esp ... tub-layout. As stated the stub from first C should be connected to L3 (which is power according to stackup) and I do think this should be L2 which is supposed to be GND.

Is the output impedance the same as ESP32-C3? I found here https://esp32.com/viewtopic.php?t=21649 that it should be: (30 ~ 40) ±10 jΩ
Or is the package already matched internally to 50Ω?

[ESP_Minatel]

Regarding the POWER plane layer question:

https://docs.espressif.com/projects/esp ... #rf-tuning

粘贴的图形-2.png (100.01 KiB) Viewed 1379 times