ADS1298: Augmented Leads in digital domain

Alwyn DSouza

Part Number: ADS1298

The ADS1298 data sheet says

9.3.1.7.3.1 Augmented Leads
In a typical implementation of the 12-lead ECG with eight channels, the augmented leads are calculated digitally.
In certain applications, it may be required that all leads are derived in analog rather than digital. The ADS1298
and ADS1298R provide the option to generate the augmented leads by routing appropriate averages to channels
5, 6, and 7.

I have highlighted

"In certain applications, it may be required that all leads are derived in analog rather than digital"

What applications would required leads to be derived in analog domain using hardware vs digital domain which can be done with firmware on a MCU?

Is it mandatory according to standard (60601 and its derivatives) that all leads of ECG be derived in analog domain?

over 5 years ago

0 Alexander Smith over 5 years ago

TI__Mastermind 49041 points

Hi Alwyn,

Great question! I sent an email to another member of the team who may be able to assist.

0 Brian Pisani over 5 years ago

TI__Mastermind 38745 points

Alwyn,

There is no such requirement from IEC60601 to my knowledge. The "requirement" mentioned in the datasheet comes down to customer preference. It is much more power and space efficient to do the derivation in software.

Brian

0 Alwyn DSouza over 5 years ago

Intellectual 360 points

Hi Alexandar / Brian,

If there is no such constraint on analog / digital then why is the feature provided on chip. Which applications would use that feature and why?

0 Alexander Smith over 5 years ago in reply to Alwyn DSouza

TI__Mastermind 49041 points

Hi Alwyn,

As Brian said, it's to provide flexibility to support the customer's preference. As mentioned in the paragraph, it's for 12-lead ECG systems.

0 Alwyn DSouza over 5 years ago in reply to Alexander Smith

Intellectual 360 points

Hi Alexandar,,

I gather that even for 12 Lead ECG systems the Augmented leads can be calculated in digital domain, Even the ADS1298 ECG demostration kit. Just measures Lead I and Lead II in analog domain and derives the remaining leads (Lead III, AvR, AvL, AvF) from the first 2 leads.

I understand about the customer preference part but was just wondering why would a customer go in for analog and add extra hardware since acquiring these leads in analog domain would need more than 8 channels for a 12 lead ECG, so more number of chips would be utilized.

0 Alexander Smith over 5 years ago in reply to Alwyn DSouza

TI__Mastermind 49041 points

Hi Alwyn,

Perhaps the customer prefer's doing it their own way in the analog domain due to performance, wanting to do something else with the signal, etc.

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ADS1298: Augmented Leads in digital domain