Bio-potential AFE reduces power use

Texas Instruments Inc. launches the ADS1293 24bit, 3-channel analogue front end (AFE) for bio-potential measurement applications. The device supports one to five leads with a single AFE, thus, cutting the size, power consumption and overall cost of portable, battery-powered electrocardiogram (ECG) solutions, Holter monitors and wireless patient monitoring equipment.

The AFE uses 300µW for each channel, and each channel can be programmed for a specific sample rate and bandwidth, so customers can optimise the configuration for performance and power. Each channel also features simultaneous digital ECG and pace signals so there is no need for a dedicated pace channel, which contributes to the reduction of power consumption. The AFE has built-in error detection with an alarm pin, relieving the controller from continuously polling for error conditions, and it allows independent shutdown on any functional blocks that are not in use.

The AFE integrates three 24bit delta sigma ADCs, four low-noise instrumentation amplifiers and EMI-hardened inputs, right leg drive amplifier, lead-off detection, and Wilson and Goldberger terminals. These features optimise signal path gain stages, eliminating the need for analogue filters and reducing board space requirements. Also, the AFE enables programmable settings for DC and AC lead-off detection to increase design flexibility.

To simplify and speed system design with the ADS1292, the company releases the WEBENCH Medical AFE Designer online design tool. They can then download configuration data to the ADS1293 evaluation module (EVM), reducing design time from weeks or months to a matter of minutes.

This evaluation module's development tool provides a user-friendly GUI with an interactive block diagram, which allows designers to try different system configurations with the chip quickly and easily. ECG and pace data can also be captured and saved for post processing. The ADS1293 development tool is also available online in the WEBENCH Medical AFE Designer.

The ADS1293 is available in a 5mm x 5mm QFN package for Rs.291.01 ($5.50) in 1,000-unit quantities. The ADS1293EVM can be purchased for Rs.5,238.10 ($99).