A 0.57 mm² Platform with 70.7% Efficient 4 mA 3.2 V Charge Pump and a Current-Input Ramp ADC for Implantable Optical Sensing of Tumors

Continuous and real-time in vivo monitoring of solid tumors using implanted sensors would be transformative for precision health in cancer research and treatment. Optical techniques such as spectroscopy offer a path towards realizing such treatments, but require additional miniaturization efforts. To address this need, we have designed and prototyped an integrated circuit (IC) for implantable in-vivo optical sensing of tumors. Our prototype, fabricated in 65nm CMOS technology, occupies a 0.57mm ² active area and comprises a high-efficiency cross-coupled charge pump and two current-input ramp analog-to-digital converters (ADCs). The charge pump, with a peak efficiency of 70.7%, delivers 12.8 mW to power the off-chip light sources necessary for spectroscopy. We validate our approach through measurements on a tissue simulating phantom and demonstrate the prototypes suitability for in vivo optical sensing.