A 200 MHz elliptic OTA-C filter in GaAs technology

Design consideration for fully integrated continuous-time filters operating at very high frequencies are presented. The OTA was designed in TriQuint's 1 mu m GaAs depletion-mode technology; the design considerations include frequency response, linearity, output impedance, tunability, stability of the common-mode output signal, temperature and wire inductances. In order to obtain the highest possible frequency response, the frequency limitations caused by the parasitic parameters are emphasized. As a result, an OTA with 7 GHz -3 dB frequency and very small parasitics, and a filter with 200 MHz cut-off frequency are designed.<>