A 0.41mW Band-Tunable 6^th-Order IF Filter with 40 ns Settling Time in 45 nm CMOS RFSOI

A 5.5–7.5‐GHz band‐configurable wake‐up receiver fully integrated in 45‐nm RF‐SOI CMOS

“…Compared to [47], the 2 nd -order BPF here has two main following optimizations. First, it is designed to be not only band-tunable, but also have a pass-band voltage gain adaptability from 0 to 3 dB.…”

“…The sixth‐order IF BPF is optimised based on the work presented in [47]. It is constructed using three same 2 nd ‐order BPFs based on the Tow‐Thomas g m ‐C filter topology introduced in [48].…”

“…The second main improvement of the OTAs in this work is the reduction of the leakage current, by the means that the power switches and the current mirrors are also replaced with thick‐oxide‐gate transistors. The four OTAs are implemented based on the OTA presented in [47], which also utilises an improved folded cascode structure introduced in [49]. To enable digital tuning of g T 0 , the tail current of the input differential pair of the OTA is designed to be digitally definable.…”

“…Figure 11 shows the proposed current reference. This current reference re‐uses the circuit topology proposed in [47], and is optimised for a minimal leakage current by application of only thick‐oxide‐gate transistors without prolonging the settling time. Two identical resistors R 3 generate a reference voltage of $$\frac{1}{2}\cdot {V}_{\text{DD,AFE}}$$.…”

“… Block diagram of the proposed 2 nd ‐order band‐pass filter (BPF) based on [47]. Compared to [47], this 2 nd ‐order BPF provides both voltage gain and frequency tunability, includes a 3‐bit DAC and has much lower leakage current due to usage of thick‐oxide‐gate transistors …”