A Novel Capacitive Peaking Amplifier for Transmitters

A broadband peaking amplifier using capacitors instead of inductors is proposed. The amplifier exploits an RC network as the degeneration element in a common differential pair which adds a pole-zero pair to the main system. All possible configurations for peaking in such a system is analytically discussed and it is shown that the only way to increase the bandwidth is to set the zero before the pole of the main amplifier and also the added one. To prove this; a peaking amplifier with 26.5GHz bandwidth with a Bandwidth Enhancement Ratio (BWER) of 3.8 and output swing of 800 mVp-p with 43mW power dissipation in 0.18µm standard CMOS technology is designed. The effect of bonding wire on the output matching is studied and it is shown that the effective -3dB bandwidth of the circuit increases by taking the bonding wire into account.

Keywords:

Bandwidth Enhancement , Broadband Amplifier , Line Driver , Peaking Amplifier