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LAUNCHXL-CC1350: Need help with Power problems!

Intellectual 390 points

Replies: 3

Views: 45

Part Number: LAUNCHXL-CC1350

Hi experts,

I have designed my custom PCB using cc1350 LP reference and MSP430 using structure as below:

I use a power switch to turn on/off power for main power of CC1350 board. After i turn off the power, using multimeter to measure Vin of cc1350 i got voltage is immediately down from 3.3V to 2.2V and then take along time to down to 0V. i disconnect TX line of MSP430 and do the same thing as above, but i got the voltage is suddenly down to 0.6V and then slowly down to 0V. Could you tell me what is my problems and what do i have to do to fix it?

Thank you very much!

  • Guru 248415 points

    See the "Absolute Maximum Ratings" in the datasheet. 

    If you set VDDS on CC1350 to 0 V but have an input to CC1350 that is not 0 V you are most likely powering part of the chip through ESD diode leakage.

    Since you are using a switch, is the < 1 uA shutdown/ standby current of CC1350 too large? 

     OOO until November 25th

  • In reply to TER:

    Hi, TER

     The < 1 uA shutdown/ standby current of CC1350 is not large for our system. 

    But could you give me some solution to get 0V?

  • Guru 248415 points

    In reply to Minh Tran35:

    If you want to set VDDS = 0 V, you have to ensure that all other (inputs) to the chip is 0 V before you set VDDS = 0 to ensure that the absolute maximum ratings are correct. 

     OOO until November 25th