A 90nm CMOS Variable-Gain Amplifier and RSSI Design for Wide-band Wireless Network Application

Abstract

A VGA (variable-gain amplifier) integrated with RSSI (received signal strength indicator) function is designed and implemented in a 90nm CMOS technology. Employing closed-loop amplifier, the VGA chain achieves 500MHz bandwidth with 45dB variable gain. The IIP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (third order input referred intercept point) of the VGA is measured to be as high as 19dBm, meanwhile the NF (noise figure) is 16dB. The RSSI linear range is approximately 65dB for plusmn0.3dB linearity error. The VGA chain consumes 13mA from 2.5V single supply voltage. The test chip active area is 650 mum times 550 mum