Tunable mixed-mode OTA-C universal filter

Abstract

A novel electronically tunable mixed-mode universal biquad by using four single-output and one dual-output-operational transconductance amplifiers, two grounded capacitors is proposed. The proposed circuit has ability to realize voltage, current, transconductance, and transresistance mode, and can the following advantageous features: (i) realization of low-pass, band-pass, high-pass, notch, and all-pass filter responses from the same configuration, (ii) employment of only grounded capacitors ideal for integrated circuit implementation, (iii) orthogonal controlling of x o and Q for easily electronic tunability, and (iv) low active and passive sensitivity performance. Finally, to verify our architecture, we have designed this analog filter chip with TSMC 0.35-lm 2P4M CMOS technology. This chip operates to 1 MHz and consumes 30.95 mW. The chip area of the analog filter is about 0.823 mm 2 .

Electronically Tunable Current Controlled Current Conveyor Transconductance Amplifier-Based Mixed-Mode Biquadratic Filter with Resistorless and Grounded Capacitors

“…Hence, mixed-mode circuits are worthy of study. Many types of mixed-mode circuits have been developed [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], utilizing assorted types of active elements such as conventional second-generation current conveyors (CCIIs) [13,14], current feedback operational amplifiers (CFOAs) [15], differential voltage current conveyors (DVCCs) [16], differential difference current conveyors (DDCCs) [17], fully differential current conveyors (FDCCIIs) [18], four-terminal floating nullors (FTFNs) [19], operational transconductance amplifiers (OTAs) [20][21][22], current controlled current conveyors (CCCIIs) [23][24][25], and current controlled current conveyor transconductance amplifiers (CCCCTAs) [26,27]. High [13] 7 CCII 2C + 8R 7 CCII [14] 3 CCII 3C + 4R + 2 switch 3 CCII [15] 4 CFOA 2C + 9R + 1 switch 4 CFOA [16] 3 DVCC 2C + 3R 3 DVCC [17] 3 DDCC 2C + 4R 3 DDCC [18] 1 FDCCII 2C + 3R 2 DDCC [19] 3 FTFN 2C + 3R 3 × 2 CFOA [20] 7 OTA 2C 7 OTA [21] 5 OTA 2C 5 OTA [22] 4 OTA 2C 4 OTA [23] 4 MOCCCII 2C 4 MOCCCII …”

Voltage-mode universal biquadratic filter with one input and five outputs using two DDCCTAs

“…The DDCCTA has a transconductance stage at its back end and hence it provides the feature of electronic tuning to the circuit parameters, while also reducing the number of resistors by one. The DDCCTA device is obtained by cascading of the differential difference current conveyor (DDCC) [1,2,3] with the operational transconductance amplifier (OTA) in monolithic chip for compact implementation of analog function circuits [6]. Therefore, a lot of interesting researches have been devoted to the realization of DDCCTA-based voltage-mode multifunction/universal biquadratic filters [7,8,9,10].…”

Design of a 4.5-V, 450-mA low-dropout voltage linear regulator based on a cascoded OTA

“…Hence the unity gain bandwidth is varied by varying the load capacitance to obtain the suitable phase margin (PM) according to the application and hence assuring the stability of the system. In the proposed design (m 4,5 ) and (m 13,12 ), (m 3,6 ) and (m 11,14 ), (m 15,16 ) and (m 7,8 ) form the cascoded pairs with current mirroring. The main design criterion of the proposed OTA is same as the classical OTA design which depends on the Equations (3), (4), and (6).…”