Table 3. Lna Noise Figure Predictions and Measurements

LNA, the author stated that there were other sources of noise outside of the amplifier that added to the noise figure, such as board parasitics as well as noisy bias components. The author further stated that the prediction of the model presented here is similar to the noise figures presented in similar CMOS LNA's.[4] IV. Conclusion A complete model for the drain current noise for MOSFET devices in the saturation region has been presented. This model accounts for mobility degradation, DIBL, CLM, as well as electron temperature. Also, an intuitive model for the noise induced by the substrate current Isub at high drain voltages was presented. These models were shown to match well with observed noise data presented in earlier papers. From these models, a few key guidelines can be extracted. The models in this paper, as well as the observed data, indicate a severe increase in the noise at high electric fields, making it imperative that as device geometries are reduced, terminal voltages must be reduced as well, to minimize the electric fields existing in the channel. Also, in order to achieve a minimum amount of noise, the device should be biased at low (V g-V t) in order to keep the device acting as a long-channel device. However, the (V g-V t) should be small enough to avoid the peak in the I sub-V g curve. 5 for the noise enhancement at high drain voltages; the prediction in [9] gets less accurate with increasing V ds. The method proposed in this work makes this enhancement factor a function of the terminal voltages, improving the prediction of the drain current noise. This variation in the effective multiplication factor M used in the model derived in this work is shown in Figure 3. Figure 4 plots the predictions of drain noise current given by Eq. 12, Eq. 16, and Eq. 17. Plotting the noise currents in this manner emphasizes the significant contribution of the noise induced by the shot noise in I sub at high drain voltages. Data for two devices was also taken from [10], whose characteristics are shown in Table 2. Figure 5 shows a comparison between the measured values of the noise enhancement factor γ (not to be confused with the body effect coefficient) and those predicted by the model presented in this work for Device A. γ is defined to be a multiplicative factor used to …