800 MHz universal quad clock for complex timing solutions

February 20, 2015 // By Graham Prophet
XR81411 is a quad output, high frequency LVCMOS/LVDS/LVPECL configurable clock synthesiser that generates any frequency in the range of 10 MHz to 800 MHz with four independent PLLs, using a flexible delta-sigma modulator and a wide ranging VCO. The clock outputs have very low phase noise jitter of sub 0.2 psec while the part uses extremely low power.

The chip can be used with a standard crystal or an external system clock and each independent output can be configured to select from four different frequency multiplier settings to support a wide variety of applications. Each clock synthesiser includes an integer/fractional divider allowing output frequency resolution of less than 2 Hz intervals.

“The XR81411 extends our universal clock family to multioutput solutions for various end applications,” said James Lougheed, vice president, component products. “The ability to independently configure each output as LVCMOS, LVDS or LVPECL at any frequency makes this an ideal solution for switches/routers, AV timing and FPGA clocking.”

Crystal input frequency is 10 MHz to 60 MHz, parallel resonant crystal. Output frequency range covers 10 MHz to 800 MHz, while the VCO range is 2 GHz to 3 GHz. The chip has configurable outputs either as a differential LVPECL/LVDS pair or as a single-ended LVCMOS.

The RMS phase jitter is <0.6 ps at -125 MHz (12 kHz to 20 MHz) and <0.2 ps at -125 MHz (1.875 MHz to 20 MHz).

The device comes in a 5 x 5mm LGA package, prices start at $10.50 (1000).

Exar; www.exar.com/xr81411