A Switched-Capacitor Band-Pass Biquad Filter Using a Simple Quasi-unity Gain Amplifier

Hugo Serra (1) , Nuno Paulino (1) , João Goes (1)

1 ULISBOA - Universidade de Lisboa = University of Lisbon

This paper presents a switched-capacitor (SC) band-pass biquad using a simple quasi-unity gain amplifier. In sub-nanometer CMOS technologies the intrinsic gain of the transistors is low; this increases the difficulty of designing high gain amplifiers. The proposed SC filter is based on the Sallen-Key biquad and it requires only a simple low gain amplifier. A differential filter circuit, including a suitable amplifier based on a fully-differential voltage-combiner is presented and analyzed. The correct functionality of this circuit is validated through electrical simulations of a second-order band-pass filter. These simulations show that, for a clock frequency of 100 MHz, the frequency response of the circuit is similar to the corresponding prototype filter.

Mots clés: Analog circuits; band-pass Sallen-Key; switched-capacitor circuits; voltage-combiner amplifier

Domaines: Informatique [cs]

Hugo Serra, Nuno Paulino, João Goes. A Switched-Capacitor Band-Pass Biquad Filter Using a Simple Quasi-unity Gain Amplifier. 4th Doctoral Conference on Computing, Electrical and Industrial Systems (DoCEIS), Apr 2013, Costa de Caparica, Portugal. pp.582-589, ⟨10.1007/978-3-642-37291-9_63⟩. ⟨hal-01348805⟩