A 5-b 10-Gsample/s A/D converter for 10-Gb/s optical receivers

A 5-bit 10-Gsample/s A/D converter (ADC) is fabricated in a SiGe BiCMOS process to digitally compensate the signal distortion in a 10-Gb/s optical receiver. A fully differential, flash-type ADC has a wideband track-and-hold amplifier to mitigate the timing skew, followed by high-speed comparators with very small metastability error. It achieves a 4.1 effective bits at low input frequencies and 2.8 effective bits at full-scale 4.9-GHz input signal at 10-Gsample/s.