HMC985 Series

The HMC985 devices are absorptive, voltage variable attenuators (VVAs) which operate from 10 GHz to 40 GHz or 20 GHz to 50 GHz and are ideal in designs when an analog dc control signal must be used to control RF signal levels over a 35 dB dynamic range. They feature two shunt-type attenuators which are controlled by two analog voltages, VCTRL1 and VCTRL2. Optimum linearity performance of the attenuators is achieved by first varying VCTRL1 of the first attenuation stage from −3 V to 0 V with VCTRL2 fixed at −3 V. The control voltage of the second attenuation stage, VCTRL2, should then be varied from −3 V to 0 V with VCTRL1 fixed at 0 V. However, if the VCTRL1 and VCTRL2 pins are connected together, it is possible to achieve the full analog attenuation range with only a small degradation in input IP3 performance. Applications include AGC circuits and temperature compensation of multiple gain stages in microwave, point-to-point, and VSAT radios.ApplicationsPoint-to-point radiosVSAT radioTest instrumentationMicrowave sensorsMilitary, ECM, and radar