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CC2530: About the RF input saturation and ADC input resistence

user1392992
Prodigy 70 points

Part Number: CC2530

Hi,

As RF RECEIVE SECTION shows there,

“

Saturation (maximum input level) 10 dBm
PER = 1%, as specified by [1]

[1] requires –20 dBm


(1) Difference between center frequency of the received RF signal and local oscillator frequency.

”

Does the details above mean Saturation value (10dBm) is measured under the condition that the received power difference between the center frequency of recieved signal and local oscillator signal is 20dB meanwhile the acceptable PER（Packet Error Rate) is 1%?

在ADC CHARACTERISTICS

Input resistance, signal Using 4-MHz clock speed 197 kΩ

If  other crystal of different frequency is adopted, how much would the resistance will be or will it be in a range?

Best regards,

Jie

2020/9/7

  • 0
    TI__Guru**** 317180 points

    The input level is typically set to ensure that the voltage swing in the input will not be too high. Meaning that 10 dBm will give voltage levels close to the maximum rating of the chip.

    ADC: The resistance scales with the frequency. But, from the UserGuide: "The ADC should only be used with the 32-MHz XOSC, and no system clock division should be implemented by the user. The actual ADC sampling frequency of 4 MHz is generated by fixed internal division. " meaning that the ADC should only use 4 MHz clock. Since this is a sigma delta ADC the behavior of ADC will change if the clock frequency change hence to ensure datasheet numbers, 4 MHz should be used.  

  • 0 in reply to TER
    Prodigy 70 points

    Thanks for detailed information of ADC resistence.

    The saturation value of RF input is suggested for protecting CC2530 from malfunction or failure, which reminds me of being cautious in dealing with its RF behaviour,thanks again.

    However, could it be possible let us know how 10dBm is  measured,calculated or evaluated?

     

    Best regards,

     

    Jie

     

    2020/9/8

  • 0 in reply to user1392992
    TI__Guru**** 317180 points

    Most RF generators are not able to give higher output power than 10 dBm which  limits what we can test in an automated system meaning that we have a few measurements that go up to +10 dBm in RX but not higher. 

    Do you expect input powers higher than 10 dBm? Normally the output powers on the 2.4 GHz band is lower and should typically be an issue. 

  • 0 in reply to TER
    Prodigy 70 points

    Thanks you.

    We suppose several CC2530 Voltage Probe( by their own ADCs and RF sections)  modules working in a stacked styleclosely together since they share a CR2032 as the only DC supply in common.

    We suppose they simultaniously measure once a second and transmit the data with their PCB antennas outside an equipment enclosed cabinet ( a  MW transmitter controller).

    We suppose those module send datas in high power since the Zigbee router or coordinator outside need strong signal as enough as possible.

    So those transmitted data become very strong input signal to other modules nearby.

    Is there any advice?

    Best regards,

    Jie

    2020/9/10

  • 0 in reply to user1392992
    TI__Guru**** 317180 points

    First I would test to see how much power you actually receive on some of the RX nodes with this setup. 

    Mount the antennas as planned and connect one board where you program it to send a CW with the planned output power. With a spectrum, measure the received power on the other antennas. If this is actually close to 10 dBm or higher we can see if you can find a solution. 

  • 0 in reply to TER
    Prodigy 70 points

    Thank you.

    We would like to know how much it is possible for us to realize the idea. 

    Where would we meet problems or what are possible key factors?

    Best regards,

    Jie

    2020/9/10

  • 0 in reply to user1392992
    TI__Guru**** 317180 points

    A bit difficult question to answer since I don't know how your device looks like. I hope it should be easy enough,  hopefully you are able to access the antenna that will be used in RX with a cable so you are able to do measurements on this. 

  • 0 in reply to TER
    TI__Guru**** 223697 points

    CC2530 Zigbee power consumption questions are being handled in a separate thread: https://e2e.ti.com/support/wireless-connectivity/zigbee-and-thread/f/158/t/939447 

    Regards,
    Ryan