The output of the mixer core is taken directly from its open collectors. The open collector outputs present a high impedance at the IF frequency. The conversion gain of the mixer depends directly on the impedance presented to these open collectors. In characterization, a 100 . load was presented to the part via a 2:1 impedance transformer. The device also features a power-down function. Application of a logic low at the PWDN pin allows normal operation. A high logic level at the PWDN pin shuts d