A 46pJ/pulse analog front-end in 130nm CMOS for UWB impulse radio receivers

This paper presents an integrated ultra-low power analog frontend architecture for UWB impulse radio receivers. The receiver is targeted towards applications like wireless sensor networks and body-area networks typically requiring ultra energy-efficient, low data-rate communication over a relative short range. The proposed receiver implements pulse correlation in the analog domain to severely relax the power consumption of the ADCpsilas and digital backend. Furthermore a fully integrated prototype of the analog front-end, containing an analog pulse correlator, a linear-in-dB variable gain amplifier and a 4-bit ADC, is demonstrated. Several design decisions and techniques, like correlation with a windowed LO instead of with a matched template, exploiting the duty-cycled nature of the system, operation in the sub-1 GHz band as well as careful circuit design are employed to reach ultra-low power consumption. The analog front-end was manufactured in 130 nm CMOS and the active circuit area measures only 600 mum times 730 mum. A maximum channel conversion gain of 50 dB can be achieved. The AFE consumes 1.44 mA at 1.2 V power supply and operates at a pulse rate of 37.5 Mpulses per second. This corresponds to an energy consumption of 46 pJ/pulse which is by far best-in-class. A wireless link over more than 3.5 m in an office-like environment has been demonstrated which makes the proposed receiver well suited for the targeted applications.