Terminations when driving DAC904 with ICS552-02 clock buffer 1

[sparkyyyyy]

Hello,

I am using a ICS552-02 clock buffer with a 33 Ohm resistor in series (manufactures suggested 33 Ohms) to drive a DAC904 D/A converter at 100 MHz. The power supply for both the ICS552-02 and DAC904 are 3.3 Volts. The logic threshold for the DAC904 is 1/2 supply voltage which is 1.65 Volts.

I have a line length of about 6 inches. The rise time of the ICS552-02 can be as low as 0.6 nano seconds. The prototye board was not layed out to using stripline guidelines. I am planning on cutting the traces and running RG-174 coaxial cable from the clock buffer to the D/A converter. If I terminate the load with 50 Ohms, my drive voltage to the DAC904 will be 1.65 Volts which is the trigger threshold. I think I may need to leave the input to the DAC open and only use the 33 Ohm resistor at the clock buffer output or use some kind of AC or Thevinin termination. Any suggestion are appreciated.

Thank you.

 

[bogeyman]

100pf in series with the 50 ohm will leave the dc conditions at 1/2 vcc, then maybe fiddle the 33 ohm till it works over the range of conditions required.

 

[sparkyyyyy]

Thank you for your input.

Have a great day.

Thank you,


George