In this paper, we discuss the feasibility of creating an UltraSound (US) communication circuit to wireless transmit outside the body diagnostic information from multiplexed biosensors chip built on the top layer of a drinkable CMOS Body Dust cube. The system requires to be small enough (lateral size of less than 100 um) to mimic the typical size of a larger blood cell (diameter around 30 um for white cells) and so support free circulation of the cube in human tissues. The second constraint came from the low-power consumption requirement, with the energy provided by an external US base station. The results of the feasibility study demonstrate the possibility to design an architecture for a data transmission transponder by using a 0.18μm CMOS process, with sub-10 uW of power consumption and a total chip area of 43x44 um^2. The paper also discusses the limits of the designed system and the need for further improvements toward real applications in Body Dust diagnostics.