ESP8266 Community Forum

- Fri Apr 10, 2015 4:36 am #14085

impedance matching.png

The datasheet of ESP8266 says that the impedance matching circuit should of 50 ohms. The ESP-01 uses a L-C-L filter. The value of capacitor is 5.6pF. What should be the value of incutors? How do I calculate it? The inductors are named "NC", what does that mean?

Please help me.
Thanks in advance

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- Fri Apr 10, 2015 5:58 am #14091 Impedance matching circuit for ESP8266 is base on the PCB stackup. if PCB is 1mm high is different from 1.6 mm PCB. Or 2 layer or 4 layer.
And it also based on distance from top layer to GND below.
Height of microstrip wire going to antenna. ( 1 Oz, 0.5 Oz)
Distance for microstrip to GND on both sides
PCB material Dielectric constant (as 4.4...)
So, my best offer is to copy existing design and after production use L C component according to recommendation from RF expert that use VNA device to check your PCB.
see http://tinyurl.com/oromxl4

Kind regards,
Dr. Nissim Zur
Bluetooth Smart, Wi-Fi IoT expert
CTO Elinistech
Skype nissim.test
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Email nissim@vitelix.com