Minimal two‐transistor multifunction filter design

Abstract

Summary This paper presents a comprehensive method and analysis on the design of two‐transistor multi‐output filters where three possible functions are simultaneously available. Although two transistors are employed at its core, proper biasing does not require additional passive components. A total of thirteen valid second‐order filters are reported, and several of them are experimentally tested using discrete transistors as well as simulated using Spectre in a BiCMOS process. A fully differential realization of a MOS‐C band‐pass filter, based on one of the structures found, is designed and then used to realize a fourth‐order Chebyshev band‐pass filter. Copyright © 2017 John Wiley & Sons, Ltd.

High‐order realisation of MOSFET‐only band‐pass filters for RF applications

“…Table 5 summarises the significant performance parameters of the proposed filters. The main properties of the high-order filters, MOSFET-only filters, and TAM filters in [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] and the proposed ones are summarised in Table 6 (see the Appendix for details).…”

“…There are many published high-order band-pass filters (BPF) in the literature [3][4][5][6][7][8][9][10][11][12][13]. Acar and Ozoguz [3] reported an nth order voltage transfer function which can be obtained using signal-flow graph approach.…”

“…BPF with high‐order employs lossy and lossless integrators as well as grounded capacitors. Maundy , et al [13] presented a method on the design of VM two‐transistor multi‐output filters. However, these circuits can be included an external resistor, capacitor and inductor in addition to transistors.…”

“…Similarly, another circuit contains five transistors, two resistors and two capacitors to provide a BPF. Likewise, possible filters obtained using two transistors and passive elements have been given in the paper [13]. It is clearly observed from previously published works mentioned above that external passive elements especially capacitors have been utilised in high‐order filter structures.…”

A current‐mode MOSFET‐C analog filter for the high‐frequency band applications

“…Another attempt to approach high transconductance values with acceptable linearity is to use MOS transistors as transconductors. [6][7][8][9][24][25][26][27] Also, intrinsic C gs capacitances of them give rise to MOS-only designs. [28][29][30][31][32][33][34] Even though they bring low power consumption with small chip area, nonlinear intrinsic capacitances of the MOS devices deteriorate adjustability of the filter structure.…”