| 摘要 |
An input buffer amplifier has a symmetrical centroidal layout. The input buffer amplifier includes two half differential amplifiers that have substantially identical layouts. Each half amplifier receives the input signal in-parallel, and the outputs of the differential half amplifiers are wire-ored together. The input buffer amplifier is symmetrical about both horizontal and vertical lines of symmetry. Furthermore, FET devices forming the half amplifiers are interlaced to create the horizontal line of symmetry. The overall horizontal and vertical symmetry of the input buffer amplifier improves the device matching between differential signal paths. In other words, the devices in the half amplifiers that process the positive and negative components of the differential signal are more closely matched. This reduces differential offsets and common mode offsets that can occur when devices are not matched properly. The reduction in differential offset and common mode offset improves the linearity and dynamic range of input buffer amplifier. The improved differential matching also reduces signal distortion and the susceptibility to power supply noise.
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