1-3hit |
Toshiyuki UMEDA Shoji OTAKA Kenji KOJIMA Tetsuro ITAKURA
This paper describes a low-power-supply 2-GHz CMOS up-converter. A current-mode mixing method using current adding and self-switching mixers is proposed for 1-V operation. The current-mode up-converter achieves conversion gain of 6.7 dB and linearity of 6.5-dBm OIP3 at 1 V. Balanced configuration and DC offset canceller reduce LO leakage below -40 dBc even with 20-mV Vth mismatches. The bias circuit of the IC is designed to maintain constant conversion gain for variation of temperature for practical usage. The measurement results indicate the proposed up-converter is applicable for future wireless systems.
This paper reviews analog-circuit researches in the 1990's especially from an academic-side point of view with the aim of pursuing what becomes important in the 21st century. To achieve this aim a large number of articles are surveyed and more than 200 are listed in References.
Process and device technologies of CMOS devices for low-voltage operation are described. First, optimum power-supply voltage for CMOS devices is examined in detail from the viewpoints of circuit performance, device reliability and power dissipation. As a result, it is confirmed that power-supply voltage can be reduced without any speed loss of the CMOS device. Based upon theoretical understanding, the author suggests that lowering threshold voltage and reduction of junction capacitance are indispensable for CMOS devices with low-voltage supply, in order to improve the circuit performance, as expected from MOS device scaling. Process and device technologies such as Silicon On Insulator (SOI) device, low-temperature operation and CMOS Shallow Junction Well FET (CMOS-SJET) structure are reviewed for reduction of the threshold voltage and junction capacitance which lead to high-seed operation of the COMS device at low-voltage.