A HSPICE behavioral macro model for the floating-gate ion sensitive field effect transistors(ISFET)is founded based on the site-binding model
the static output characteristics.Transfer characteristics of the ISFET and the relationship between the pH value and interface voltage are simulated.Simulation results show that the model and the theory of ISFET are correspond with experimental data.It provide important theoretical reference for design of differential integrated ISFET/REFET sensor chip.