A 2.3μW wireless intraocular pressure/temperature monitor

We present the design of an ultra-low power, wireless capacitance/temperature sensing device for continuous intraocular pressure monitoring. The device is wirelessly powered and demonstrates a power consumption of 2.3μW at 1.5V during continuous reading. The chip converts both capacitance and temperature to frequency using a time-interleaved relaxation oscillator, which modulates RF backscatter to a reader for computation of measured samples. The chip exhibits measured capacitance and temperature standard deviations of 1.4fF and 0.4°C, respectively.