Signal routing in high-frequency systems requires reliable switches. For higher-power signals where speed is not an issue, designers often prefer the robust performance of electromagnetic (EM) switches. For lower-power signals where switching speed is important, diode or FET switches provide low-cost solutions. There is one other switch alternative, however, that blends the characteristics of EM and diode switches. The model M1C06-CDK2 switch from Dow-Key Microwave Corp. (Ventura, CA) incorporates microelectromechanical system (MEMS) technology to achieve 40-dB isolation from DC to 6 GHz with low power consumption and high reliability.
The model M1C06-CDK2 is a single-pole, double-throw (SPDT) bipolar latching MEMS switch that is rated for 100 million switching cycles. It employs gold contacts to maintain low-loss electrical connections even after millions of operations, and low-power magnetic actuation to shift the position of a short-travel cantilever from open to closed to effect latched switching. Bipolar voltage pulses of ±5 V set and reset the switch, which can handle input-power levels to 2 W CW. The linear device achieves a third-order intercept point of no less than +60 dBm and typically +65 dBm.
Although not on a par with the nanosecond switching speed of diode devices, the M1C06-CDK2 nonetheless achieves switching time of less than 200 µs and typically less than 50 µs. The insertion loss is 0.2 dB to 3 GHz and 0.5 dB to 6 GHz while the isolation is rated for 45 dB to 3 GHz and 40 dB to 6 GHz. The SPDT switch exhibits return loss of at least 20 dB to 3 GHz and at least 14.5 dB to 6 GHz.
In (quasi-hermetic) package form, the MEMS switch measures 5.88 × 5.88 × 2.78 mm; as a die, it is 1.96 × 1.64 mm. It typically consumes 140 mA current (170 mA maximum) at set/reset voltages of ±5 VDC, with no standby power (0 W) required. The switch is rated for operating temperatures from 40 to +85ºC and is functionally tested under 10 g's vibration and 20 g's shock levels. Dow-Key Microwave Corp., 4822 McGrath St., Ventura, CA 93003-7718; (805) 650-0260, FAX: (805) 650-1734, Internet: www.dowkey.com.