ADS1299: Why does datasheet example for DC Lead-off detection enable AC lead-off detection at fDR/4?

Ankit Parikh1

Part Number: ADS1299

Hello,

In section 10.1.2.1 of the latest (Revised Jan 2017) ADS1299 datasheet, the dc lead off example suggests setting LOFF register to 0x13

This contradicts the register description which says that

Bit 4: is reserved and should be always 0

FLEAD_OFF[1:0]: These bits should be 00 for DC lead-off

Is this is a mistake in the datasheet?

If it is, then should the correct value for LOFF be 0x00 for enable DC lead-off detection with lead off current set at 6 nA and comparator threshold set to 95%P and 5%N?

Ankit

over 1 year ago

0 ChienChun Yang over 1 year ago

TI__Mastermind 19815 points

Hi,

You are probably correct. The pseudo code section may have mistake.

If setting

The LOFF register values are -

bit 4 should stay 0.

Thanks

0 Ankit Parikh1 over 1 year ago in reply to ChienChun Yang

Prodigy 50 points

I think the probability of this being a mistake in the datasheet is 100% based on our testing and your response

I hope that TI amends the datasheet to avoid further confusion. And also advises any users who use the example.

Like in this thread the user talks about DC lead-off and uses the example from the datasheet and there is no mention of the mistake.

https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/898606/ads1299-lead-off-detection-issues?tisearch=e2e-sitesearch&keymatch=ads1299%2525252525252520dc%2525252525252520lead-off#

regards

Ankit

0 ChienChun Yang over 1 year ago in reply to Ankit Parikh1

TI__Mastermind 19815 points

Thanks for the advice.

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ADS1299: Why does datasheet example for DC Lead-off detection enable AC lead-off detection at fDR/4?