Alignment-Independent Chip-to-Chip Communication for Sensor Applications Using Passive Capacitive Signaling

We propose a capacitive coupling based method for sensor data retrieval that can be easily integrated with miniature sensor nodes of sub-mm scale. To enable passive operation of the sensor chip, the data retrieval chip sends power to/receives signal from the sensor chip simultaneously. An alignment detection and pad reconfiguration mechanism is implemented to allow convenient read-out without precise positioning. A test chip was fabricated in 0.13 mum CMOS technology. The silicon measurement results demonstrate <15% difference in achievable data rate can be obtained when the sensor chip is randomly dropped on the data retrieval chip regardless of alignment.