Design tradeoffs in a triode transconductor for low voltage zero-IF channel select filters

In this paper, we study the tradeoffs in operating the low voltage triode g_m cell proposed by Enz at higher operating frequencies as a candidate for use in a zero-IF channel select filter. The tradeoffs in transconductor parameters are presented by introducing a current split factor design approach. It is determined that increasing the bias current in the feedback path increases the bandwidth of the g_m cell at the expense of decreased tuning range and linear range. Results presented are simulated using a 0.35 mum digital CMOS process for a V_DD of 1.8 V. These are useful in the preliminary design of reconfigurable filters for multi-standard receivers.