An 802.15.4 IR-UWB Transmitter SoC with Adaptive-FBB-Based Channel Selection and Programmable Pulse Shape

In this chapter, we explore the use of adaptive back biasing to tune RF characteristics in wireless transmitters for ultra-low-power operation. To this end, we design an 802.15.4 impulse-radio (IR) UWB transmitter in 28 nm FD-SOI where back biasing is used to tune (1) the RF carrier frequency to the desired channel and (2) the RF output power to meet the spectral regulations. The transmitter is based on a digital PLL-free architecture for frequency synthesis with a pulse-shaping digital power amplifier. These architectural features combined with the FD-SOI capability to operate the transmitter at ultra-low-voltage (0.55 V) up to 4.5 GHz enable state-of-the art efficiency (2.6%) and extremely low energy per bit (≪1 nJ/bit).