Latching micro magnetic relays with multistrip permalloy cantilevers

Abstract

This paper describes recent progresses on the development of a new type of latching micro magnetic relay that has recently been demonstrated. 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 (/spl lsim/93 /spl mu/J, switching current /spl sim/60 mA, minimum switching pulse width /spl sim/0.2 ms); (3) low voltage operation (/spl sim/5 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 (/spl lsim/50 m/spl Omega/); (7) operation in ambient environment; (8) lifetime >5/spl times/10/sup 6/ cycles at 240 /spl mu/A, (9) batch fabrication using planar processing methods. We report new results on latching relays with multistrip permalloy cantilevers to improve the operation stability and with an off-center flexure bar to decrease the contact resistance.