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ADS1298 Pacemaker out pins

Santoshkumar Gurral
Intellectual 270 points
Other Parts Discussed in Thread: ADS1298

Hi,


ADS1298 IC has two paceout signal pins  TESTP_PACE_OUT1 (from Even channels) TESTN_PACE_OUT2 (from odd channels), why is this ?

why two paceout lines ? is it for redundancy purpose ?


Can i connect any one of  either TESTP_PACE_OUT1 or  TESTN_PACE_OUT2 signal to an external hardware pace detect circuit (differentiator, window comparator, SRlatch) and still can successfully detect a pace signal from ECG input signal

Santosh

  • 0
    TI__Mastermind 38745 points
    Hey Santosh,

    From my understanding, there are many kinds of pacemakers with electrodes stationed at different places around the heart. Since typical ECG measurement schemes provide for multiple "perspectives" of the same event (namely the cardiac cycle), it reasons to say that one perspective might be better for seeing an event than another. The different "perspectives" are the different lead combinations which are routed to different channels on the ADS1298. Given that pacemakers may be placed differently for different products and that stimulation may occur at different parts of the cardiac cycle, it might make sense to look at a couple of different "perspectives" when detecting a pacemaker.

    On this device, the two PACEOUT amplifiers provide you with the ability to route two separate channels out of the device simultaneously. This is to provide you with flexibility to be thorough when implementing a pacemaker detection strategy.

    You are correct with your idea about connecting external pacemaker detection hardware to either the TESTP_PACE_OUT1 pin or the TESTN_PACE_OUT2 pin. The decision of which pin to connect them to depends on which channel you'd like to monitor for a pacemaker pulse. The even numbered channels can be routed to TESTP_PACE_OUT1 and the odd numbered channels can be routed to TESTN_PACE_OUT2.

    Regards,
    Brian Pisani
  • 0 in reply to Brian Pisani
    Intellectual 270 points

    Hi,

    ADS1298 does it have any power sequencing requirements ? particularly any sequence required in AVDD (analog supply voltage) and DVDD (digital supply voltage) power up.

    which supply should be up first AVDD or DVDD ?

    or no sequence required, ie it does not matter either AVVD is up first or DVDD is up first .

    Thanks,

    Santosh

  • 0 in reply to Santoshkumar Gurral
    TI__Mastermind 38745 points
    Hey Santosh,

    The sequence does not matter as long as you either send the RESET command or toggle the RESET pin after at least 128 ms has transpired since the last supply rail has stabilized to its final voltage.

    Regards,
    Brian Pisani