Title :
High dynamic range variable gain amplifier for CDMA applications
Author :
Kasashima, M. ; Tachi, S. ; Tanaka, K.
Author_Institution :
Electronics Components Group, Oki Electr. Ind. Co. Ltd., Tokyo, Japan
Abstract :
A new attenuator and threshold voltage (Vth) compensation circuits using GaAs MESFETs were designed and developed and this circuit was applied to develop a variable gain amplifier (VGA) for CDMA cellular phone systems. This VGA is packaged in an 8 pin plastic package and demonstrated high dynamic variable gain range (80 dB/100 MHz 70 dB/250 MHz 55 dB/500 MHz). High gain of 60 dB is observed for 85 MHz with low power consumption (Vdd=+2.7 V, Idd=6 mA). Since depletion mode MESFETs are used no negative supply is needed for gain control.
Keywords :
III-V semiconductors; MMIC amplifiers; UHF amplifiers; UHF integrated circuits; attenuators; cellular radio; code division multiple access; compensation; field effect MMIC; gain control; gallium arsenide; 2.7 V; 6 mA; 60 to 80 dB; 85 to 500 MHz; CDMA applications; GaAs; GaAs MESFET; MMIC chip; attenuator; cellular phone system; depletion mode MESFETs; gain control; high dynamic range amplifier; plastic package; threshold voltage compensation circuits; variable gain amplifier; Attenuators; Cellular phones; Circuits; Dynamic range; Gain; Gallium arsenide; MESFETs; Multiaccess communication; Plastic packaging; Threshold voltage;
Conference_Titel :
Microwave Symposium Digest, 1997., IEEE MTT-S International
Conference_Location :
Denver, CO, USA
Print_ISBN :
0-7803-3814-6
DOI :
10.1109/MWSYM.1997.604412
