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ADS1293 - some questions

Other Parts Discussed in Thread: ADS1293, ADS1192, ADS1292, ADS1291, ADS1298

Hi all

Would you mind if we ask ADS1293?

<Question1>
Our customer would like to set to the datarate 125SPS or 250SPS of  ECG waveform Acquisition.(like as the datasheet  P7 of ADS1192)
So, our recognition is the followings; 
-OSC=3.84MHz
-ODR125Hz, 250Hz
-fs: 384KHz, R1= 2 or 4, R2= 6, R3= 128
And then we cann't understand whether it is possible to change Fs(SDM) by adjusting OSC or not.

<Question2>
What is the difference between ADS1293 and ADS1292 about Pace detection? 
It's only internal Pace detection circuit or external, isn't it?

Kind regards,

Hirotaka Matsumoto

  • Hi team,

    We think that your team is so busy, and we are sorry to bother you.
    However, could you let us know these?

    Kind regards,

    Hirotaka Matsumoto

  • Hello Matsumoto-san,

    The ADS1293 does not come from the same family of devices as the ADS1291/92. Instead, it comes from the SVA Precision Signal Path product line. Sergio will have to give you more details about the ADS1293 pace detection features, but it looks like the device offers digital pace detection on-chip, and an option for external pace detection in analog.

    In contrast, the ADS1291/92 does not offer any built-in circuitry for pace detection. The ADCs cannot sample fast enough for digital pace detection. Therefore, customers would have to design an external circuit converts the PGA differential output to a single-ended signal and provides additional gain. Then, the signal could be passed through an analog slope detection circuit, or it can be digitized by a high-speed SAR ADC to capture the pacemaker pulse in the digital domain.

    An example hardware pace detection circuit can be found in the following TI Design: www.ti.com/lit/ug/slau511/slau511.pdf. For software pace detection, please have a look at the new application section in the ADS1298 datasheet. The ADS1298 already converts the differential PGA output to a single-ended signal, so this must be added externally to the ADS1291/92.

    I hope this helps.

    Best Regards,

  • Ryan san

    Thank you for your reply about Question2.

    So, if you have the reply of Question1, could you let us know?

    Kind regards,

    Hirotaka Matsumoto

  • Matsumoto-san,

    It appears you are trying to configure the ADS1192 for an output data rate of either 125 SPS or 250 SPS. To do this, you must first provide a CLK frequency of either 512 kHz or 2.048 MHz and set the CLK_DIV bit appropriately. The modulator is intended to sample at 128 kHz. Then, you can configure the data rate by setting the CONFIG1[2:0] bits as outlined on page 37.

    You have some flexibility in the input CLK frequency, but 3.84 MHz is beyond the acceptable range listed in the Electrical Characteristics table.

    I did not completely understand your first question:

    -OSC=3.84MHz

    -ODR125Hz, 250Hz

    -fs: 384KHz, R1= 2 or 4, R2= 6, R3= 128

    And then we cann't understand whether it is possible to change Fs(SDM) by adjusting OSC or not.


    Were you asking about ADS1192? I do not see where these resistor values are coming from.

    Best Regards,

  • Ryan san

    Thank you for your reply.
    No, we mentioned using ADS1293. not ADS1192.

    We would like to acheive the followings;
    -ODR(ECG)125Hz, 250Hz

    We guess that  the output data rate of an ECG channel can be calculated as follows:
    ODR(ECG)=Fs / R1 R2 R3

    Could you understand our request?

    Kind regards,

    Hirotaka Matsumoto

  • Hello Sergio,

    We need your support.

    (I set tag to only ADS1293).

  • Table 8, 9, 10 and 11 of the ADS1293 provide you several option to select ODS rates  to fulfilled sampling rate covering 125SPS or 250SPS . The SDM of the ADS1293 was design for the specified frequency given in the EC table of the ADS1293, change of external OSC is not recommended. 

    The difference between ADS1293 and ADS1292 pace detection is that ADS1293 in addition to providing analog pacer signal  externally ( for use for external circuit to detect pacer condition), it provides digitized pacer data output that can be read via SPI and processed by software for detecting the pacer signal.  The digital pacer data is available at the same time as the digitized ECG signal. The ADS1292 does not have the digital pacer detection feature. 

  • Bahram san,

    Thank you for your reply.

    You mentioned that "Table 8, 9, 10 and 11 of the ADS1293 provide you several option to select ODR rates  to fulfilled sampling rate covering 125SPS or 250SPS".
    On the data sheet Table 8,9,10 and 11, we can't find ODR 125SPS and 250SPS.
    Could you let us know what you designated?


    Kind regards,

    Hirotaka Matsumoto

  • Apparently you can not use say 130, and 260 sps instead of 125 and 250 sps. In this case you may want to use a different part in the portfolio.
  • Bahram san

    If you don't know, could you ask your team or the people who has knowledge of ADS1293?  
    Because, our customer are waiting for the reply.
    So, we have to hurry to reply.

    And then, what did you indicate 130, and 260 sps? We didn't mention 130, and 260 sps.

    We need your help.

    Kind regards,

    Hirotaka Matsumoto

  • Hi team,

    As the result, it can't correspond for ODR 125SPS and 250SPS, can it?
    We guess that your days are so busy, but could you let us know?

    Kind regards,

    Hirotaka Matsumoto

  • As I mentioned  previously, the data rates are as provided in the ADS1293 datasheet. If you  need to get exactly 125/250 SPS, then you would need to use the other parts in the portfolio.

  • Bahram sanOK, thanks.
  • Baharam san,

    OK, thanks.

    Kind regards,

    Hirotaka Matsumoto