A Continuous-Time Field Programmable Analog Array Using Parasitic Capacitance Gm-C Filters

Abstract

Field programmable analog filters (FPAAs) often lack the necessary bandwidth for high performance applications. This paper presents an FPAA based on G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> -C filters, which achieves routing without the use of transmission gates. Not only can the parameters of these filters be tuned, but also their order and structure. No additional capacitor is used for integration, only the MOS parasitic capacitances. A maximum bandwidth of 164 MHz has been achieved in simulations based on a 130 nm 1.2 V CMOS process. Distortion performance is high with a HD3 of less than -70dB for a 50mV@1MHz signal. Influences of parasitic capacitances are simulated using a test chip with 49 G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> -cells arranged in a hexagonal array.