we used two pieces of ad9648 on our project .
the problem is that there is a certain probability that ad9648 can‘t start work,for example,you boot it 100 times, 20 times the ad9648 wouldn't start work.
the FPGA give the differencial clock to the ad9648,the PI6C485311 is a 1-to-2 Differential to LVPECL fanout buffer.
we found that changing the R43 and R62 have the efffect on result.
R43=R62=240Ω,the clk Vpp=250mv, about 20% possibility ad9648 can‘t start work.
R43=R62=24Ω,the clk Vpp=400mv,about 5% possibility ad9648 can‘t start work.and some of them are always able to start work
R43=R62=100Ω,the clk Vpp=800mv,about 50% possibility ad9648 can‘t start work.
how to change the R43 R62 can solve the problem ?
Thank you for using AD9648. I'm sorry about the trouble.
1. it is dead.
2.the clock frequency is 62mhz
3 yes the clock is always running but the ad9648 is sometimes dead
4 sorry,i measuerd it again , 240ohm is about 600mv Vpp .100ohm is about 800mv 24ohm is about 400mv.
5.i tried 15ohm and the Vpp is about 550mv
may i have your email?plz
I believe it was a typo, but you mentioned "15ohm". You meant 150 Ohm, correct? With the 150 Ohm pull-down resistors, how was the startup success percentage?
Are you able to send a more complete schematic of the circuitry and components around the AD9648?