This work presents the AC analysis of smart microactuator system. The electro-thermal microactuator is modelled in VHDL-AMS and integrated with its driving circuit using Cadence AMS tools. A new design approach is used to generate a variable low frequency oscillator signal. The high voltage driving AC signal is generated by a DC/DC converter biasing an amplifier fed by the variable frequency oscillator. The simulation shows that the MEMS actuator can reach its peak and ambient temperature when powered by a low frequency pulse while the beams of the actuator are not capable to reach their full sweep when the pulse width is low.