Multiple input and/or gain stage Gilbert cell mixer designs are disclosed. The designs allow one input to be turned on at a time, and are suitable, for example, for use in receiver and transmitter applications. In addition, the designs allow for the inputs of the multi-input Gilbert cell mixer to be connected together, thereby allowing for switching of gain stales within the Gilbert cell mixer. T he mixer design may include, for example, a Gilbert cell mixer stage, and a plurality of input/gain stages. Each input/gain stage has its output connected to the input of the mixer stage, and is configured for receiving an input signal and applying a gain factor to that input signal to provide a signa! for mixing with the LO. Each input/gain stage is configured with stage select circuitr) for enabling or disabling that stage, so that only one input/gain stage is active at a time.
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