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TDC1000-GASEVM: Change filter limits

Luigi Truppa
Intellectual 385 points

Part Number: TDC1000-GASEVM
Other Parts Discussed in Thread: TDC1000, TDC7200

Hi,
i have recently bought TDC1000-GASEVM and TDC1000-TDC7200 boards and i'd like to have some informations about the filters.
I need to use transducers with frequencies that are out of these limits.
In particular, i have to use 1Mhz transducer for TDC1000 GASEVM and 400 kHz transducers for TDC1000-TDC7200EVM.
TDC1000 TDCGASEVM band-pass filter has 58 kHz as lower limit and 312 kHz as upper limit.
The idea is to change C32 (512 pF) with a 150 pF capacity (so the upper limit increases to 1.06 MHz).

 

TDC1000 TDC7200 has 582 kHz as lower limit and 3 MHz as upper limit.
Here i'd like to change R31 (5.36 kOhm) with 10 kOhm resistance in order to decrease the lower limit to 312 kHz.

The question is: can i do this?
If i'll change the resistance/capacity the other components will burn because of an excessive current?
The gain will change?
Thank you!

Regards, 
Luigi

  • 0
    TI__Mastermind 31655 points

    Hi Luigi,

    You will not run into passive component life issues unless something goes seriously wrong with the entire system. I have attached a TINA simulation that will allow you to test different component values to arrive at the bandpass transfer function you need for your application. This simulation is currently set to a 1Mhz center frequency.

    3108.1MhzFilter.TSC

    I also recommend that you read the receiver filter section of the TDC1000 datasheet which includes formulas for calculating the proper component values for the frequencies you desire. You can then test those values in the simulation.


    Regards,

  • 0 in reply to Scott Cummins
    Intellectual 385 points

    Thank you, i will try!