Field programmable analog arrays (FPAA) offer the electronic equipment designers new possibilities in quick, interactive and flexible design process, simple verifying, prototyping and modifying of many circuit solutions. The detailed research results of the selected parameters of the AN221E04 device delivered by Anadigm (R) are presented. Some features not mentioned in the data sheets were noted and analyzed, concerning e. g. the device input and output filters. Based on the examined AN221E04 device the example application of the automatic gain control (AGC) circuit was built. The advantages of this design, its obtainable parameters and the problems involved by application of FPAA are presented in the paper.