A Cryogenic Active Router for Qubit Array Biasing from DC to 320 MHz at 100 nm Gate Pitch

To address the semiconducting qubit biasing bottleneck, we develop a cryogenic analog demultiplexer operating 64 independent channels at 4 K and integrating a realistic 20 $\mu$m to 100nm pitch reduction compatible with dense qubit arrays. We achieve <0.22% crosstalk while maintaining 0.44 $\mu$V/s maximum voltage drift. Our active router allows DC to >100MHz signals to target static qubit polarization as well as fast (down to 3ns) voltage pulses for qubit manipulation. From the extracted power consumption (3.54$\mu$W/MHz/channel), we can extrapolate the thermal budget required to control future large-scale qubit arrays.