A 6-to-38Gb/s capture-range bang-bang clock and data recovery circuit with deliberate-current-mismatch frequency detection and interpolation-based multiphase clock generation

This paper reports a bang-bang clock and data recovery circuit (BBCDR) with an ultra-wide capture range. The circuit exhibits automatic frequency capture and phase locking over a wide 6-to-38 Gb/s range without using a frequency detector, allowed by a recently proposed deliberate-current-mismatch technique. Moreover, we accurately obtain an eight-phase clock through analog interpolation of quadrature signals over the whole wide frequency range by introducing a tunable capacitor array before an inverter-based phase interpolator. A 65-nm prototype of the developed BBCDR occupies an area of 0.07 mm(2) and attains a bit error rate of less than 10(-12) under a continuously variable input frequency, with a total power consumption of 24.6 mW for a 32-Gb/s non-return-zero input, thus leading to 0.769-pJ/bit energy efficiency.

Automated summary

This paper presents a bang-bang clock and data recovery circuit (BBCDR) that has an ultra-wide capture range. The circuit achieves automatic frequency capture and phase locking over a wide range without using a frequency detector, thanks to a deliberate-current-mismatch technique. Additionally, the circuit accurately obtains an eight-phase clock across the entire frequency range through analog interpolation of quadrature signals. A 65-nm prototype of the BBCDR has been developed, which occupies an area of 0.07 mm(2) and achieves a bit error rate of less than 10(-12) under continuously variable input frequency, with a power consumption of 24.6 mW, resulting in an energy efficiency of 0.769 pJ/bit.