Importance

Loading Importance Indicators...

Abstract

The invention relates to phase detectors that integrate a portion of a transition between adjacent or consecutive bits of a serial bitstream in a relatively fixed window by switching currents as opposed to voltages. The phase detector can be used to synchronize a VCO clock in a PLL to a fast data bitstream used in an optical network, such as SONET. Advantageously, embodiments of a current mode phase detector switch currents, rather than voltages, to integrate the window of the serial bitstream. The current switching allows devices to operate at frequencies approaching the device's f.sub.T and can advantageously extend the phase detector's bandwidth and allow an associated transceiver to operate at higher data rates. By contrast, the conventional switching of voltage results in a delay induced by the charging of related capacitances, such as parasitic substrate capacitances, which in turn results in actual performance far below the f.sub.T of the devices.

Loading the Abstract Image...

First Claim