HMC985LP4KE (ANALOG DEVICES)

The HMC985LP4KE is an absorptive GaAs MMIC Voltage Variable Attenuator (VVA) which operates from 10 to 40GHz and is ideal in designs where an analogue DC control signal must be used to control RF signal levels over a 35dB dynamic range. It features two shunt-type attenuators which are controlled by two analogue voltages, Vctl1 and Vctl2. Optimum linearity performance of the attenuator is achieved by first varying Vctl1 of the first attenuation stage from -3 to 0V with Vctl2 fixed at -3V. The control voltage of the second attenuation stage, Vctl2, should then be varied from -3 to 0V with Vctl1 fixed at 0V. If the Vctl1 and Vctl2 pins are connected together it is possible to achieve the full analogue 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.