CC3100: DC voltage on CC3100 when in TX and RX

Jeff Coletti

Part Number: CC3100

Hi Support team

I am a little short in info, my customer is debugging his pcb in China right now and sent me this question, can you answer

We have a bit of an urgent question - I'd normally call but am in China right now.

We need to know exactly what the expected output voltage is on the CC3100 RF output pin, RF_BG when in RX mode and when in TX mode.

Can you tell us what we should expect to see?

Thanks

Jeff

over 7 years ago

0 Charles Oladimeji over 7 years ago

TI__Mastermind 33805 points

Hi,

Assuming you have 50Ohms RF route and you are operating at 18dBm the voltage is 2.512 V

see link below

http://ifmaxp1.ifm.uni-hamburg.de/DBM.shtml

18dBm = 0.0634W

P = V^2 / R

0.0634 = V^2 / 50

V = 1.776V RMS = 2.512V peak

0 Jeff Coletti over 7 years ago in reply to Charles Oladimeji

TI__Expert 8645 points

HI Charles

Was just getting ready to add some more info, what about in receive mode, customer is working with an RF expert on optimizing the match/ antenna performance and is asking for this in receive mode.

Thanks
Jeff

0 Charles Oladimeji over 7 years ago in reply to Jeff Coletti

TI__Mastermind 33805 points

it is the same calculation

0 Jeff Coletti over 7 years ago in reply to Charles Oladimeji

TI__Expert 8645 points

Hi Charles

I guess I am not asking the questions correctly. We want to know the voltage that the RF input is at when in receive mode. So basically if the device was in an RF chamber with n RF sources, and was in receive mode, what would the voltage be on the RF input measured with a DC meter?

Thanks
Jeff

0 Charles Oladimeji over 7 years ago in reply to Jeff Coletti

TI__Mastermind 33805 points

Hi Jeff,

Using a DC meter you should get 0V. You can confirm this by comparing the result on the customers board with the launchpad.

Regards,

Charles O

0 Jim Griszbacher76 over 7 years ago in reply to Charles Oladimeji

Prodigy 80 points

Hi Charles and Jeff,

This was originally my question through Jeff.
I think I wasn't clear enough on my original question and need to clarify.

For impedance matching purposes, I need to know if the S11 of the RF port is the same with the IC unpowered as it is when the unit is in receive mode. Can you provide feedback?

Thanks,
Jim

0 Jim Griszbacher76 over 7 years ago in reply to Charles Oladimeji

Prodigy 80 points

Hi Charles and Jeff,

This question had originally been posted by Jeff on my behalf, and I think I need to clarify as I did not originally ask correctly.
We need to know if the S11 of the RF ports on the CC3100 are the same with the unit powered and in receive mode versus with the unit completely unpowered.

Can you provide some insight?

Thanks,
Jim

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CC3100: DC voltage on CC3100 when in TX and RX