In this paper, we propose an automatic design procedure for the synthesis of a cascode LNA with inductive source degeneration. The proposed method is based on the precise characterization of noise figure, input impedance and gain. The design procedure is implemented in a C++ environment using a BSIM3v3-based tool for transistor sizing and a symbolic computation tool for circuit characterization. SystemC AMS can then be used to perform a system level simulation of a complete RF receiver using precise model of the LNA. Considering the complete equivalent model for the transistors and the inductors, two LNAs operating at 2.4 GHz and 935 MHz are synthesized and characterized for a 130 nm CMOS process. The generated accurate model is then used in a high-level simulation of a complete QPSK-based RF receiver to study the effect of the LNA noise figure on the Bit Error Rate of the receiver.