A PVT-robust current-mode passive mixer with source-degenerated transconductance amplifier

A current-mode passive mixer with conversion gain that is robust to process, supply voltage, and temperature (PVT) variations is presented. The passive mixer includes a transconductance amplifier having a source degeneration capacitor. The conversion gain of the current-mode passive mixer is proportional to the ratio of the source degeneration capacitance C_S to the load capacitance C_L. This technique eliminates the need for extra PVT compensation circuitry. Moreover, the conversion gain of the mixer can be designed to be programmable without relying on any gain detecting circuitry. A test chip fabricated in a 90-nm CMOS process demonstrates the PVT-robustness of the proposed mixer.