Enhanced Linearity in Intracranial Pressure Monitoring System Through Sample Isolation Bridge ROIC

This study presents a sample isolation bridge readout integrated circuit (ROIC) specifically designed for intracranial pressure (ICP) monitoring systems. The ROIC consists of an instrumentation amplifier (IA) and a successive approximation register (SAR) analog-to-digital converter (ADC). Additionally, the output of the IA is isolated to protect against output spikes that could compromise the linearity and stability of the ROIC. Both traditional and proposed ROIC circuits are fabricated using 0.18 µm complementary metal-oxide-semiconductor (CMOS) technology. The peak signal-to-noise ratio (SNR) for the traditional ROIC is 40.9 dB, while the peak signal-to-noise and distortion ratio (SNDR) is measured at 40.1 dB. In contrast, the proposed ROIC, which incorporates the SAR ADC, achieves a peak SNR of 54.6 dB and a peak SNDR of 51.8 dB, demonstrating a significant improvement in linearity. The new ROIC consumes 39.5 µA of current from a 1.8 V power supply and occupies a chip core area of only 0.27 mm2.