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 in-band and out-of-band linearity. Conventional RX architectures are limited in gain, sensitivity, and linearity arising from supply dependence ($V_{\mathrm{DD}}$) leading to significant performance degradation when processing multiple signals of varying strengths. Both the trans-impedance amplifier (TIA) and the voltage amplifiers in conventional RXs especially in advanced technology nodes induce distortion and clipping in dynamic 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 double-sampled VCO-based voltage-to-time converters (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 (OOB) IIP3 of +10dBm, while consuming only 18mW.