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Original question:

Long distance mic sensor signal transmission

DRV135: DRV135 or alternative for differential mic signal over 300m

murali kandasamy
Intellectual 350 points
Part Number: DRV135
Other Parts Discussed in Thread: INA134, , INA137

Hi,

In my application a differential MEMS microphone signal is to be driven over max. 300m where a differential ADC is used to sample it. DRV135 is a single to differential line driver. Is there similar drivers for differential input or is any differential amplifier suitable for my requirement? Is an amplifier at the receiver end like INA134 enough without an amplifier at the sensor end?

Thanks,

Murali 

  • 0
    Guru 140200 points
    Hi Murali,

    differential signalling also called balanced signalling is commonly used when signals have to be transmitted over a long distance. Any common mode noise injected into the cabling can be removed by this method, because the differential signals are subtracted from each other in the receiver. Assume your wanted signal is 1V and -1V at the output of balanced driver DRV135 and 100mV common mode noise is superimposed to the signals, then your signals arriving at the receiver are 1V + 0.1V and -1V + 0.1V. After subtracting the signals in the receiver you get 1V + 0.1V - (-1V) - 0.1V = 1V + 1V. So, the wanted signal is doubled and the common mode noise is eliminated.

    To make a differential signalling work you need a balanced driver AND a differential receiver!

    Datasheet recommends the INA134 or INA137 as receiver.

    Kai
  • 0 in reply to kai klaas69
    TI__Genius 11135 points
    Murali

    We haven't heard back from you so we assume this answered your question. If not, post another reply below, or create a new thread if this one has timed-out.

    Thanks
    Dennis