ADS1298: AC lead-off excitation signal frequency limitation

Fabian PARIZEL

Part Number: ADS1298

Hello,

Our system (EEG monitoring system) use AC Lead-off feature to measure electrode impedance.

Currently we see in datasheeet that excitation signal frequency is limited to FLEAD_OFF = 61,5 Hz (Due to FS/4 with FS set to 250Hz)

Could you tell us if there is any solution to reduce this excitation frequency?

Is it possible to set FS to 125Hz?
Or maybe a way to set FLEAD_OFF = FS/8?

Thank you.

over 3 years ago

0 Fabian PARIZEL over 3 years ago

Prodigy 31 points

Hello,

I make a mistak, i would say FLEAD_OFF = 62,5 Hz

0 TCT over 3 years ago in reply to Fabian PARIZEL

TI__Genius 11550 points

Hi Fabian,

Thank for the post.

Unfortunately, the AC leadoff frequency is fixed at fDR/4. There is no option in the device to change this setting. You can operate the device with an external clock frequency of 1.024MHz to reduce the DR to 125Hz. However, we cannot guarantee the performance of the device for this operating frequency.

Thanks.

-TC

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ADS1298: AC lead-off excitation signal frequency limitation