16- and 24-bit ECG/EEG AFEs focus on portable biopotential measurement applications

April 05, 2012 // By Paul Buckley
Texas Instruments Incorporated (TI) has expanded the company’s award-winning ADS1298 analog front end (AFE) family with five new fully integrated AFEs for portable biopotential measurement applications.

The new electrocardiogram (ECG) and electroencephalograph (EEG) AFEs are the first to offer 16- and 24-bit resolution with 1 or 2 channels. The devices cut power consumption by more than 94 percent compared to discrete implementations, while shrinking board space requirements up to 86 percent. These reductions will enable portable medical, sports and fitness equipment that combines long battery life with a form factor that is smaller, lighter and easier to wear.
The new AFEs reduce board space, system complexity and power consumption: Integrate low-noise programmable gain amplifiers (PGAs), test signals, a right leg drive amplifier, oscillator, voltage reference and lead-off detection function to simplify design, while significantly reducing board space requirements and cutting power consumption to only 335 µW/channel.

The AFEs support AAMI, IEC requirements and feature input-referred noise below 8 uVpp to support Association for the Advancement of Medical Instrumentation (AAMI) and International Electrotechnical Commission (IEC) end-equipment performance requirements.

Common applications for the new AFEs in the ADS1298 family include Holter and fitness heart-rate monitors. Customers can expect the following power and space savings when used in these applications:

  1. A two-channel Holter based on the ADS1292 consumes 94-percent less power while using up to 92-percent less board space and 92-percent fewer components than an equivalent discrete implementation.
  2. When used in a typical fitness heart-rate monitor, the ADS1291 consumes 89-percent less power while using 52-percent less board space and 75-percent fewer components compared to discrete implementations.
  3. Devices in the ADS1298 family integrate all of the key functions needed for these medical and fitness applications, enabling customers to focus development efforts on firmware, FDA approvals, field testing and more, rather than hardware design.

TI offers a variety of tools and support to speed development with the entire ADS1298 family, including an IBIS model to verify board signal integrity requirements and evaluation modules (EVMs) to speed evaluation. EVMs for the new AFEs can be purchased for $99 and include the