I have some questions about our circuit design (HMC659+HMC914).
Please help take a look at the attachment and give me some advice. Thank you.
HMC914 input is a CML and the input common mode is equal to VDD. The 3.3V +/-0.4 is an acceptable spec. The AMR should be updated to
We do not recommend operating the input over VDD+0.5V.
Let us know if you have additional questions or comments.
Thank you for the reply.
We will try to modify the circuit as attached file. But we are not sure if the both input signals
to INN and INP are no problem or not due to using a negative voltage. If our circuit might damage HMC914,
please let me know what are problems.
Your proposed circuit might be ok only at very low frequency operation. At higher frequencies, there is likely issues with the proposed circuit. We do recommend that you attenuate the RF signal to less then 0.8Vpp. This is a more robust solution and would not impact the performance at any frequency.
We can use HMC914 up to 12.5Gbps if we attenuate the RF signal to less than 0.8Vpp as you recommend?
Yes, You should be able to operate HMC914 up to 12.5 Gbps with single ended input signals of less than 0.8Vpp.