Source-follower-based bi-quad cell for continuous-time zero-pole type filters

A large input range source-follower based bi-quad filter cell

“…The filter offers 2 complex poles and 2 complex zeros in a single biquad stage, without increasing the power consumption with respect to previous work [1,2,3]. A 4th order elliptical filter was designed based on this new topology and simulations were performed to confirm correct…”

“…Chebyshev II and elliptic filter stages. In [3], two cross-coupled feedthrough capacitors are added to yield those necessary zeros. Though only partly, as when the transconductances of the transistors are kept equal only imaginary zeros occur (see Fig.…”

“…As is clear in [3], the transconductance of the pMOS and nMOS transistors could be used as an additional degree of freedom, though this would affect the noise performance. Furthermore, tuning the transconductance of pMOS and nMOS transistors separately is hard to realize in the improved topology of [2].…”

Chip design of a 10-MHz switched capacitor low-pass filter for wireless application

“…Several literatures of SCFs are found [2][3] [4], and our previous study proposed a SCF with a signal bandwidth of 8.72 MHz [2]. However, its power consumption is large (44 mW) and the chip area is large (0.895 mm 2 ).…”

“…Although the power consumption and chip area are much less than those of [2], it is an advanced and expensive process of 65 nm and the stopband attenuation is only 5 dB. In [4], a source-follower-based filter is designed with less power consumption of 3 mW, but with narrow bandwidth of 2.75 MHz and bigger chip area of 1.3 mm 2 . Considering those factors of power consumption, bandwidth and chip area, a high performance of a 5 th -order SC low-pass ladder filter is presented and fabricated with tsmc 0.18-μm CMOS process.…”