A DC to 4 GHz fully differential wideband digitally controlled Variable Gain Amplifier

A Variable Gain and Attenuation control Amplifier (VGA) operating with low power, wide bandwidth and large Gain range for interfacing 60GHz RF front-end to Digital Baseband processor has been designed in 180nm SiGe BiCMOS technology from Jazz Semiconductor. The VGA is implemented using two stage amplifier followed by a Buffer stage with additional Diode linearizer for improving the input referred 1dB compression point. The performance parameters of the proposed VGA is been simulated and achieves a Gain range of -10dB to +10dB with 3-dB Bandwidth of greater than 4GHz. This VGA topology has good input and output matching. The complete circuit consumes about 9mW power from a DC 1.8V supply and the Core circuit (excluding I/O Pads) occupies a chip area of 170μm × 60μm.