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ADS1198 ECG SOC Hardware question

Alan Amin
Prodigy 70 points
Other Parts Discussed in Thread: ADS1198

Hello,

We need to use the ADS1198 FEA as an ECG unit in a single-ended input configuration; despite of TI recommendation for differential input mode for optimal operation.  

1. What absolute percussion should be taken in using Single-ended?

2. If this SOC is supplied by 3.3 V battery, can the internal VREF of 2.4V be used as the input DC bias (Common Voltage), regardless of not being the midpoint bias?

3. There are four sets of AVDD and AVSS on this chip. Can any of these sets be left floating? In other words any of these sets internally connected?

Regards,

Alan A

  • 0
    TI__Mastermind 49956 points

    Hello Alan,

    Moving your post to the Precision Data Converters Forum.

  • 0
    TI__Guru 66466 points

    Hi Alan,

    Thanks for your questions and welcome to our E2E forum!

    1. In a single-ended configuration, the negative inputs (INxN) should be tied to a common-mode voltage, preferably mid-supply. The positive inputs (INxP) should swing around the same common-mode voltage. Please refer

    2. I do not suggest using the internal reference buffer amplifier to drive the DC common-mode voltage without buffering it again. The internal amplifier will have a limited drive capability of only a few hundred uA at most.

    3. You cannot leave the AVDD or AVSS pins floating.

    Best Regards,