AR# 12667: Virtex-II/-II FPGA Pro, Virtex-4 FPGA DCM - What is the output jitter for the CLKFX? (Jitter Calculator)
AR# 12667
Virtex-II/-II FPGA Pro, Virtex-4 FPGA DCM - What is the output jitter for the CLKFX? (Jitter Calculator)
描述
What is the output jitter for the CLKFX? The parameter CLKOUT_PER_JITT_FX is listed in the Data Sheet under DC and Switching Characteristics -> DCM Timing Parameters (or Output Clock Jitter). However, the value is not listed.
The CLKFX jitter value depends on the frequency, the CLKFX_MULTIPLY (M) value, and the CLKFX_DIVIDE (D) value.
To obtain the value for Virtex-II FPGA, Virtex-II Pro FPGA, or Virtex-4 FPGA, use the CLKFX Jitter Calculator which is available in the Architecture Wizard.
NOTE: Generally, using CLKDV or CLK2X allows better output jitter than using CLKFX.