Title :
A high isolation low noise amplifier with near unit gain up to 100 MHz
Author :
De Marchi, A. ; Mussino, F. ; Siccardi, M.
Author_Institution :
Dip. di Elettronica, Politecnico di Torino, Italy
Abstract :
The authors report results obtained with a circuit in which three cascaded common base BJT (bipolar junction transistor) stages have short base leads directly connected to ground. Alternating NPN and PNP transistors biased with a bipolar supply were necessary for this purpose. The bases act as shields within the device, preventing any direct capacitive collector-to-emitter coupling; the only reverse path for the signal is represented by the small internal base resistances. The results obtained with a small number of prototypes are reported. Highlights of these are unity gain with a 3 dB bandwidth of 350 MHz, isolation in excess of 140 dB up to 100 MHz, phase noise floor at -168 dBc/Hz with corner frequency of about 300 Hz (at 13 dBm drive level), delay stability in excess of a few ps/°C at 100 MHz, and very good input and output matching to 50 Ω
Keywords :
VHF amplifiers; bipolar transistor circuits; cascade networks; circuit noise; phase noise; 100 MHz; 350 MHz; NPN transistor; PNP transistors; bandwidth; bipolar junction transistor; cascaded common base BJT; corner frequency; delay stability; direct capacitive collector-to-emitter coupling; high isolation low noise amplifier; phase noise floor; Bandwidth; Bipolar transistor circuits; Circuit noise; Coupling circuits; Delay; Frequency; Low-noise amplifiers; Phase noise; Prototypes; Stability;
Conference_Titel :
Frequency Control Symposium, 1993. 47th., Proceedings of the 1993 IEEE International
Conference_Location :
Salt Lake City, UT
Print_ISBN :
0-7803-0905-7
DOI :
10.1109/FREQ.1993.367399