We present a monostable–bistable transition logic element (MOBILE) based on the negative-differentialresistance (NDR) circuit. In particular, this circuit can be completely implemented using the standard BiCMOS process. A traditionalMOBILE using two resonant tunneling diodes (RTD) connected in series is a functional logic circuit. The fabrication of RTD is utilized in the complicated molecular-beam-epitaxy (MBE) system. However, we present a MOBILE circuit that is completely made of standard Si-basedmetaloxide-semiconductor field effect transistors and SiGe-based heterojunction bipolar transistors. By suitably determining the control voltages and input conditions, we can obtain the operation of the inverter, AND and OR logic gates. Wealso demonstrate the latch characteristic of thisMOBILE circuit. This logic circuit is fabricated using the standard 0.35 mm BiCMOS process without the need for the MBE system.