Medical-grade motion sensor for implantable applications

Phoenix, Arizona – STMicroelectronics offers the MIS2DH, an ultra-low-power 3-axis accelerometer specifically designed for medical applications, including implantable devices classified by U.S. Food and Drug Administration (FDA) as Class III. ST has many years of experience in developing custom motion sensors for leading medical-equipment manufacturers and the MIS2DH distils this expertise into an off-the-shelf solution that can enable functions such as activity monitoring and posture sensing to be included in a wide range of medical applications. 

Implantable medical devices such as cardiac pacemakers, implantable cardioverter defibrillators, and neurostimulators have been successfully used for many years to prolong the lives of patients with heart problems or to make life better for people with chronic pain conditions. Today, there is a growing interest in the medical world in exploring how new implantable devices could help treat other chronic problems such as high blood pressure, epilepsy, and tremor-related conditions. For most of these applications, an embedded accelerometer capable of measuring the activity and posture of the patient is important to manage the stimulus delivered by the implantable device and therefore to improve the effectiveness of the treatment and the wellbeing of the patient.

Until now, a major obstacle for small and medium enterprises wanting to develop innovative new medical devices has been the high costs associated with custom-designed sensors and obtaining FDA certification. The MIS2DH addresses this problem by combining a 3-axis mechanical element and an integrated electronic circuit in a single package, along with a set of collaterals required by customers seeking FDA Class III approval:

• ^{Dedicated manufacturing and testing flow, including additional checks, screening and process control}
• ^{Guaranteed retention of production records for more than 10 years}
• ^{Product-change management and notification aligned with medical standards}
• ^{Each batch is shipped with a certificate of conformity}
• ^{Long-term longevity commitment}

The MIS2DH accelerometer has been developed and produced in full compliance with the rules of ST’s medical domain, a self-regulation that ST adopted in 2012 to secure the development and manufacturing flow for products intended for use in sensitive medical applications.

"Medical researchers and electronics technology experts from companies of all sizes are interested in exploring new ways in which implantable devices could help enhance or prolong the life of people with chronic conditions, which will be an increasingly pressing problem with the world's ageing population," said Anton Hofmeister, general manager of ST’s custom MEMS division. "By combining our world-leading expertise in motion-sensing with a robust set of procedures for developing, manufacturing, and testing devices aimed at applications that meet the most stringent medical regulatory requirements, ST is contributing to important progress in this field by significantly lowering the cost and time-to-market barriers."

Key technical features of the MIS2DH include:

• 3-axis accelerometer
• Ultra-small size (2x2x1mm³)
• Ultra-low power consumption (down to 2μA in low-power mode)
• ±2g/±4g/±8g/±16g selectable full-scale
• 8-, 10-, and 12-bit operating modes
• 1Hz to 5KHz output data rate
• FIFO buffer and programmable interrupt to minimize system power consumption
•  I2C/SPI digital outputs
• 1.71V to 3.6V operating voltage

Source: STMicroelectronics