Design of Second-Order Multifunction Filter IC Based on Current Feedback Amplifiers With Independent Voltage Gain Control

This paper presents the integrated circuit (IC) design and implementation of the voltage-mode (VM) second-order gain-controlled multifunction filter (GMF), which consists of three current feedback amplifiers (CFAs), two grounded capacitors and four resistors. The design and implementation of the chip are based on a 0.18 mu m process technology, and offers the attractive advantages of high efficiency, high reliability, low voltage, low power consumption, small size and good performance. The VM-GMF chip implements low-pass (LP), inverting band-pass (IBP) and band-stop (BS) filtering functions, and can independently control the gain of LP, IBP and BS filtering functions. The chip operates with a wide input voltage of 1.2 V-pp at +/- 0.9 V supply voltage, and has a figure-of-merit (FOM) of 66.7%. The on-chip measured input power at 1-dB compression point (IP1dB) is about 7.5 dBm with good linearity and the measured power dissipation (PD) is 5.4 mW with low voltage and low power consumption. The measured phase noise (PN) at an offset frequency of 1 kHz is -100.61 dBc/Hz. The measured value of the third-order intermodulation distortion (IMD3) is -57.38 dBc and the third-order intercept point (TOI) is 21.77 dBm. Simulations and on-chip experimental measurements demonstrate the theoretical analysis of the proposed VM-GMF.