Looking a little more deeply, Figure 2 shows a SEM cross-section of the ADS1298. A robust and high yielding 0.35um, 4-layer Aluminum Bi-CMOS process has been used. The Bi-CMOS process and low noise bipolar amplifiers contribute to the low power consumption and noise performance.
Figure 2: SEM cross-section of the TI ADS1298 chip showing use of the well-established, high yield and reliable 4-layer Al 0.35-micron process.
The ADS129x series is featured in the Sotera Wireless' ViSi Mobile Patient Monitor that received FDA clearance in April 2012. This first generation system from Sotera Wireless is a hospital-based continuous vital signs monitoring system. The system is small, worn on the wrist and includes three sensors:
• Optical thumb sensor for measuring pulse rate and SpO2
• Chest sensor for measuring ECG/HR, respiration, and skin temperature
• Cuff module for single-inflation or automatic NIBP monitoring.
Figre 3: Sotera's ViSi Mobile System takes advantage of the ADS1298's small size and lower power consumption in its wrist-worn monitor. (Image Credit: Sotera Wireless)
The small size improves patient comfort and mobility. The system's low cost brings the benefits of continuous monitoring to a wider range of patients. Under development, and not yet cleared by the FDA, are versions that include additional functionality such as wireless connectivity. Sotera Wireless CTO, Jim Moon, explains the importance of the ADS129x family to their device development: "TI's ADS1298R analog front end for patient monitoring provided the means to make the ViSi Mobile Patient Monitor possible. The reduction in size and power consumption that it delivers is unparalleled."
The medical electronics design sector shares many engineering challenges with consumer electronics, with the added requirement of very high reliability. Devices such as TI's ADS129x family demonstrate that these challenges are being met and that this sector is very much worth watching for technical innovation.
Treena Grevatt is product marketing manager at UBM TechInsights, a division of UBM LLC, the publisher of EE Times.
There is a LOT of design activity in health monitoring today (we saw a ton of it on our Drive for Innovation around the country). But the challenge seems to me (still) that the digitization of records keeping is still the bottleneck to technology adoption.
We're all concerned about security. I get that. But I'm also increasingly ticked off when I have to fill out the same triplicate forms at a doctor's office using a pen. It's insane.
In any case, semiconductor and systems companies deserve big kudos for leading this charge.
Hello Dr DSP,
Thanks for the comment! You bring up a good point. However, the stringent certification and testing process is a challenge, but a necessary one. Most of the medical specifications are system level relating to patient safety. This would include the PCB, the device enclosure, and all other components within the full medical system. Getting a chip level certification to IEC60601-1 or one of the UL medical body standards is not common and would not necessarily guarantee a medical certification in the end system.
Dwight Byrd, TI Precision Data Converter Marketing Manager
One of the challenges for these designs is usually passing special certification tests or health standards. If the chip level device can be passed and then any instruments built using it passed 'automatically' or even just easier that would be a big help. Any possibility of this?