Latching microelectromagnetic relays

A new type of latching micro-magnetic relay is described and its performance results are presented. The device is based on preferential magnetization of a permalloy cantilever in a permanent external magnetic field. Switching between two stable states is accomplished by a short current pulse through an integrated coil underneath the cantilever. Some key features are summarized as follows: (1) latching (bistable); (2) low energy consumption during switching (less than or similar to 93 muJ, switching current similar to 60 mA, minimum switching pulse width similar to0.2 ms); (3) low voltage operation (less than or similar to5 V); (4) maximum dc current > 500 mA; (5) capable of various switch configurations (single-pole-single-throw (SPST), multi-pole-single-throw (MPST), or multi-pole-double-throw (MPDT)); (6) low contact resistance (similar to 50 m Ohm); (7) operation may be possible in ambient environment; (8) Lifetime expected to be comparable to other micro-relays; (9) batch fabrication using planar processing methods. (C) 2001 Elsevier Science B.V. All rights reserved.