FPGA Central

Hi,

I was wondering how accurate the clock2x of the VIRTEX 2 FPGA was. I wanted to multiply 60 MHz by two using the clock2x in order to generate a 120 MHz clk for my logic. Has anyone had experience using this and has it worked well?

Vivek,

What do you define as 'accurate'?

The CLK2X is exactly 2X the frequency (as it is generated by the use of
the delay line taps).

The CLK2X output has 2X the jitter of the CLK0 output (because it has to
make decisions on both edges of the incoming clock, so jitter is doubled).

The CLK2X output is in phase with the CLKIN and the CLK0 (every other edge).

Austin

Vivek wrote:

> Hi,
>
> I was wondering how accurate the clock2x of the VIRTEX 2 FPGA was. I wanted to multiply 60 MHz by two using the clock2x in order to generate a 120 MHz clk for my logic. Has anyone had experience using this and has it worked well?