International Journal of Computer Applications |
Foundation of Computer Science (FCS), NY, USA |
Volume 43 - Number 8 |
Year of Publication: 2012 |
Authors: Radwene Laajimi, Nawfil Gueddah, Mohamed Masmoudi |
10.5120/6126-8344 |
Radwene Laajimi, Nawfil Gueddah, Mohamed Masmoudi . Low Power Variable gain amplifier with Bandwidth of 80–300 MHz using for Sigma-Delta analogue to digital converter in Wireless Sensor Receiver. International Journal of Computer Applications. 43, 8 ( April 2012), 35-37. DOI=10.5120/6126-8344
Variable-gain amplifier (VGA) is one of the basic building blocks of many communication systems. In this paper we present a novel structure of VGA with 22 db of gain range and 220 MHz of bandwidth frequency variation. This circuit combines a voltage to current (V-I) converter and two-stage CMOS amplifier to achieve programmable gain and bandwidth . The gain is varied by changing the input voltage (Vin) from -1V to 0V. The maximum bandwidth is about 300 MHz. The gain can be varied from 38 dB to 60 dB in 1 dB gain steps. The overall circuit draws current from 10µA to 150µA at ±1. 5V power supply. The noise figure of the system at maximum gain is 18dB, and the third-order intermodulation intercept point (IIP3) at minimum gain is -8 dBm. Simulations results with static and dynamic behaviour is presented and validated with the technology AMS 0. 35µm. Eventually we have also succeeded in reducing the static power consumption to 0. 5 mW.