A Sub-10-$\mu\hbox{W}$ Digitally Controlled Oscillator Based on Hysteresis Delay Cell Topologies for WBAN Applications

This brief presents an all digitally controlled oscillator (DCO) design with two newly proposed hysteresis delay cells (HDCs) for wireless body area network applications. According to circuit topologies, the two HDCs are defined as on-off and cascaded HDCs that provide various propagation delay values. These HDCs form a simple oscillator structure based on a power-of-2 delay stage DCO (P2-DCO) architecture. Each delay stage provides half of the delay of the previous delay stage in descending order, enabling low-power and small-area features. The P2-DCO is verified in a 90-nm CMOS technology for wide operating frequencies with area of 80 μm X 80 μm and least significant bit resolution of 2.05 ps. With a supply voltage of 1.0 V, the measured dynamic power values are 5.4 and 166 μW at 3.4 and 163.2 MHz, respectively.