A 1.9-4 GHz Receiver with Enhanced In-band and Out-of-band Linearity using Double Sampling and Time-domain Processing

This paper presents an energy-efficient wireless receiver (RX) with enhanced linearity. Conventional RX architectures are limited in gain, sensitivity, and linearity arising from supply-dependence (VDD) leading to significant performance degradation when processing multiple signals of varying strengths. Both the transimpedance amplifier (TIA) and the voltage amplifiers in conventional RXs especially in advanced technology nodes induce distortion and clipping in environments comprising of multiple moving sources that alter signal strength. This work investigates scaling-friendly time-domain signal processing replacing supply-dependent amplifiers with a VCO-based voltage-to-time converter (VTC) followed by a time to digital converter (TDC) for digital readout. We enhance the VTC in-band linearity by a preceding double-sampler and overall receiver out-of-band linearity using a two-stage filtering technique including a time-domain filter implemented using switched-capacitor-based voltage feedback. The proposed RX achieves a compression point of -6dBm, an in-band IIP3 of +4dBm, and an out-of-band IIP3 of +10dBm, while consuming only 18mW.