| Popis: |
A reference-less clock and data recovery unit (CDR) for non-retiming analog crosspoint switch applications is presented. The CDR supports an eye-opening monitor (EOM) utility that facilitates adaptive equalization and is shared among all lanes, amortizing its power/area impact. Lane datarate is achieved by utilizing a fractional-N Pll, with a fixed arbitrary reference clock, and determining the correct divider settings to match to the datarate. The rotational frequency detector (RFD) used for fine tuning has often required a custom sampling and clocking network to provide the necessary samples. This design avoids the difficult design exercise by synchronizing two lower-resolution sampling networks. The CDR is designed in 65 nm, operates from 3-12.5 Gb/s, consumes 184 mW from a 1.2 V supply, and occupies 1.8 mm2. |
