Noise analysis in ultra high speed CMOS track and hold circuit
Liang H., Evans RJ., Skafidas E.
Noise performance of the switched source follower (SSF) track and hold (T/H) circuit is analyzed. Approximate expressions for the output noise of the track mode and hold mode of the T/H circuit are derived respectively. Simulations based on a commercial available 65 nm process technology are implemented with the SpectreRF circuit simulator. It is shown that the noise contribution from the parasitic capacitance is significant at ultra high frequency and the dominant noise of the SSF T/H circuit is the KT/C thermal noise. Simulations also indicate that noise contribution in track mode is more than that in hold mode and locate the major noise contributor in the SSF T/H circuit. © 2009 IEEE.