Title :
4-8 GHz band SiGe HBT variable gain amplifiers with a feedforward configuration
Author :
Kim, Chang Woo ; Chae, Kyu Sung ; Kim, Sang Mo ; Kim, Young Gi
Author_Institution :
Coll. of Electron. & Inf. Eng., Kyung Hee Univ., Seoul, South Korea
Abstract :
Broadband monolithic SiGe HBT variable gain amplifiers with a feedforward configuration have been newly developed to improve bandwidth and dB-linearly controlled gain characteristics. For bias-current control, two types of the VGA have been made: one using a coupled-emitter resistor and the other using a HBT-based current source. Both of the VGAs achieve a dynamic gain-control range of 20 dB and a 3-dB bandwidth of 4 GHz (4-8 GHz) with the control-voltage range from 0.4 to 2.6 V. At 6 GHz, the VGAs with an emitter resistor and a current source produce a maximum gain of 9.3 dB and 8.8 dB, respectively. The total bias currents are 59 mA in the VGA with an emitter resistor and 71 mA in that with a constant current source at VCTRL = 2.4 V.
Keywords :
MMIC amplifiers; feedforward amplifiers; germanium; heterojunction bipolar transistors; microwave bipolar transistors; semiconductor materials; silicon; wideband amplifiers; 0.4 to 2.6 V; 20 dB; 4 GHz; 4 to 8 GHz; 59 mA; 71 mA; 8.8 dB; 9.3 dB; SiGe; SiGe HBT variable gain amplifiers; broadband monolithic HBT; coupled-emitter resistor; feedforward configuration; Attenuation; Bandwidth; Gain control; Germanium silicon alloys; Heterojunction bipolar transistors; Power amplifiers; Resistors; Silicon germanium; Topology; Voltage control;
Conference_Titel :
Radio and Wireless Symposium, 2006 IEEE
Print_ISBN :
0-7803-9412-7
DOI :
10.1109/RWS.2006.1615094
