Burst mode packet receiver using a second order DLL

This paper describes a CDR that can be used to receive optically switched packets. Rather than using fast phase acquisition to lock onto each packet, it uses a second order delay locked loop to acquire both the frequency and phase of each source to predict future bit transitions. A 0.25 /spl mu/m CMOS prototype can track frequency offsets of 100ppm to better than 0.1 ppm and can retain lock on 10Kbit 3.125Gbps packets that occur once every 2.4Mbits.