An Improved Linearity Ring Oscillator-Based Current-to-Digital Converter
Anthony Wall, Paul Walsh, Khosrov Dabbagh Sadeghipour, Ivan O’Connell, Daniel O’Hare
Abstract
Many biosensors produce single-ended current outputs. Lab-on-chip applications demand parallel readout channels requiring low area current-to-digital converters. High HD2 has limited the Current Controlled Ring Oscillator’s adoption as a low area, single-ended converter. This work improves CCRO open loop linearity by 10 dB. A wide-bandwidth current buffer is also designed. A low area (0.0025 mm2), low power (357μW), single-ended, 1 MHz bandwidth converter suitable for array readout is presented with measured performance.
Topics & Concepts
Ring oscillatorLinearityConvertersBandwidth (computing)Current (fluid)Electrical engineeringElectronic engineeringChipCurrent sensorEngineeringComputer scienceTelecommunicationsVoltageAnalog and Mixed-Signal Circuit DesignNeuroscience and Neural EngineeringCCD and CMOS Imaging Sensors