ADS1298 VCAP pins

Jrvanho

Intellectual 730 points

Other Parts Discussed in Thread: ADS1292ECG-FE, ADS1298ECGFE-PDK

Do the VCAP pins on the ADS1x9x go through a capacitor to GND or AVSS?

In figure 74 on page 76 they are connected to AVSS. But in Fig 35 on page 29 it is connected to GND.

In the ADS1298ECGFE they are connected to AVSS but in the ADS1292ECG-FE they are connected to GND.

Can you please provide some clarification?

Cheers!

over 13 years ago

0 Tom Hendrick over 13 years ago

TI__Guru**** 181021 points

Hi Jrvanho,

You've got to look a little closer at the schematic for the ADS1298ECGFE-PDK in the back of the Users Guide. The VCAPx connection is to the lowest potential regarding the applied power. In Unipolar mode (JP 20 closed pins 1-2 and JP2 closed pins 2-3) the AVdd rail is +3V and the VCAPx caps are referenced to AGND. In Bipolar mode (JP20 closed pins 2-3 and JP2 closed pins 1-2) the VCAPx caps are referenced to AVss (-2.5V).

0 Jrvanho over 13 years ago in reply to Tom Hendrick

Intellectual 730 points

Tom,

Thanks for the information, might I recommend clarifying the data sheet as well?

Cheers!

0 Tom Hendrick over 13 years ago in reply to Jrvanho

TI__Guru**** 181021 points

Of course you can! We'll see what we can do to make the connection setup clearer and update the datasheet as soon as possible.

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ADS1298 VCAP pins