A track and hold for single-ended or differential input with adjustable output common mode

A novel differential output track and hold (TH) circuit with configurable common-mode output voltage is presented. Its structure avoids the coupling circuits required when dealing with different common-mode levels in differential signals. Another novelty of the proposed design is its ability to track single-ended signals, and convert the output to a steady differential voltage, with a programmable common-mode level. The solution employs switched capacitors arrangement that is compatible with standard CMOS technology. Circuit simulations in a 90nm technology for both single-ended and differential input confirm the ability of convert and stabilize the output common mode (CM) levels. The main drawback is a small loss of output linearity (4.81dB and 2.72dB for single-ended and differential input, respectively).