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ADS1118: PGA internal block diagram

Conor
Guru 12165 points
Part Number: ADS1118

Hi,

Can you provide the PGA internal block diagram of ADS1118?
Looking at the datasheets of other TI PGA products, it seems that the internal block diagrams are disclosed.

Thanks,

Conor

  • 0
    TI__Expert 8130 points

    Hi Conor,

    The ADS1118 achieves different gains/Full-Scale ranges by using a switched capacitor input stage where capacitors are continuously charged and then discharged to measure the voltage between AINP and AINN. 

    The internal PGA gain is not achieved through a discrete instrumentation amplifier like a PGA product would be.

    Instead, ADS1118 achieves different PGA gains / Full-scale ranges by changing the size/value of the internal sampling capacitors.

    As you can see, because of this the effective input impedance changes for different FSR / gain configurations. 

    There is no PGA internal block diagram that we could provide for you. 

    Best Regards,

    Angel