This work proposes a methodology to design linear transconductors based on three circuit topologies previously reported in literature. The design is done to be used in a synthesis tool, containing the MOS transistor model. The topologies has been analyzed using a more improved small-signal equivalent circuit of a MOS transistor to obtain a more accurate expression for the transconductance (Gm) and to extend the use for high frequencies range. A design examples in 945Mhz is given in a 130nm CMOS process.