880-01Fully integrated CMOS low noise amplifiers employing the layout optimized device and the high Q inductors are designed and successfully implemented using the 0.8 ㎛ CMOS technology. For a good noise performance of the LNA, input circuit type suitable for low noise is analyzed and the gate layout of MOSFET are optimized. Furthermore, high Q inductor technology is developed and implemented for the LNA. To integrate rf circuit as well as the high density digital and analog circuit on single chip, CMOS technology is implemented on high resistivity substrate. And the additional process for high Q inductor is developed of high quality spiral inductors without sacrificing the process complexity.
The gate layout optimized the nMOSFET show the highest $f_{max}$ of 17 GHz. And the channel width of 600 ㎛ shows the $F_{min}$ of 0.53 dB and 0.91 dB at 1.0 GHz and 2.0 GHz, respectively. The optimized nMOSFETs show the sufficient high frequency performance and low noise characteristics for LNA and other RF ICs in the frequency range of 1~2 GHz.
We proposed very simple and efficient method for enhance the inductor quality by employing the high resistive substrate and thick metal process. A 13 nH inductor's Q value reaches 12.9 that is about 7.2 times higher than that of conventional CMOS technology. The measured data shows that the 1~25 nH inductors with the Q of 4~13 range, which is comparable quality with that of GaAs technology, can be easily obtained at CMOS double-metal technology.
We successfully implemented the fully integrated LNAs employing the optimized device and high Q inductor in the 0.8 um CMOS technology. The 1.9 GHz LNA shows the gain of 15.2 dB and NF of 2.8 dB at the frequency of 1.85 GHz. The fully integrated LNA shows the lowest noise figure compared to other CMOS LNA's that usually use the off-chip, or bonding wire inductor as in/out matching element. And the circuit shows a good linear third-order intermodulation point of 4 dBm.
The fully integrated 900 MHz LNA shows the gain of 19 dB and NF of 3.25 dB at the frequency of 875 MHz. The amplifier shows a good input VSWR and high gain. Compared to other's 900 MHz LNA, which almost all the circuits use the off chip inductors, the LNA shows a comparable gain and noise performance.
