Clock Tree Generation Example

Question: How can a single oscillator output of 50 MHz distributed to 30 boards with a differential output? In addition, on each board, this input needs to be distributed to 32 devices with CMOS/TTL inputs.



First the need is 1:30 distribution, then division of the one of the 30 into 1:32 clock expansion. This can be achieved by using a CY2DP814 to drive 4 parts of CY2DP818's -- 1:4 x 1:8 = 1:32. That is a TTL/differential input (LVDS/LVPECL) to 32 outputs of LVPECL differential. It will drive 30 cables to 30 boards.

Then on each of the 30 boards you need a CY2DP814 driving 2 parts of CY29940. 1:4/2 x 1:18 = 36. That creates an LVDS/LVPECL receiver fanning out to 36 outputs of LVTTL.