Coto Technology RedRock™ MEMS-Based Reed Switch
Coto Technology RedRock™ MEMS-Based Reed Switch is ideally suited to the needs of medical, industrial, automotive, and other applications where small size, zero power operation, and hot switching capabilities are required, the RedRock™ MEMS-Based Reed Switch is a single-pole, single-throw (SPST) device with normally open ruthenium contacts.
The sensor may be actuated by an electromagnet, a permanent magnet, or a combination of both. Based on its unique high aspect ratio MEMS design and manufacturing processes, the switch provides all of the advantages of conventional magnetic reed switch technology, including zero power operation and high-power hot switching. Coto has married these features to the inherent benefits of MEMS-based design and manufacture, including item-to-item uniformity, robustness and small size by using wafer-level packaging (WLP). The resulting solution meets the demanding requirements of applications in the medical, military, and industrial markets.
The switch has a footprint of less than 1.11 mm2, 1.05mm high and is the smallest MEMS-based reed switch available on the market today.
The RedRock MEMS sensor represents the first use of High Aspect Ratio Microfabrication (HARM) to produce a commercially available sensor. HARM produces switch structures that generate contact closure forces many times greater than those exhibited by previous MEMS-based magnetic sensors, enabling hot switching up to several hundred milliwatts. Furthermore, the high retract forces developed in the sensor when it opens alleviates any tendency for the sensor to stick shut during hot switching or after long closure periods, a problem that plagued earlier MEMS sensor designs. Wafer scale packaging results in a surface mount compatible sensor with a footprint of only 1.11mm2 and a height of 1.05mm, permitting cost effective use in size-limited applications.
This new MEMS-based magnetic sensor is an ideal solution for demanding applications in medical devices such as ingestible capsule endoscopes, insulin pumps, and hearing aids. In these applications, the need for small size, zero power operation, a low parts count, and minimal circuit complexity favor passive sensors such as magnetic reeds over active magnetic sensors such as GMR or Hall devices. However, conventional reed sensors are often simply too big for such applications. Other uses for the RedRock sensor include high precision level and position sensing, and incorporation into extremely small reed relays with integrated coils developed using the same HARM technology.