Noise Filtering and Linearization of Single-Ended Sampled-Data Circuits

The performance of analog integrated circuits is often limited by the noise generated in its components. Several circuit techniques exist for mitigating the effects of the low-frequency noise. In this paper, a novel approach is described, which can also reduce even-order distortion, another major limitation of analog circuits. It may also allow the use of single-ended circuits in applications where usually differential structures are needed. In most cases, the resulting single-ended circuit will be much simpler than the fully or pseudo-differential one. It does not require common-mode feedback circuitry, nor single-ended-to-differential and differential-to-single-ended conversions at the input and output ports. The amplifiers may be single-ended, using, e.g., inverter-based circuits, and the use of baluns can be avoided. The number of pins and pads of the chip can be reduced. In addition, the single-ended opamps of the circuit may require less power than differential ones. These factors and the omission of the common-mode feedback circuits as well as the single-ended/differential converters will usually allow significant power savings.