AD9695 SYSREF DC COUPLED LVPECL TERMINATION

Hi,

Recommended matching from HMC7044/43 LVPECL driver to LVDS Receivers is as given below. Matching network provides to convert both common mode voltage and swing to LVDS compatible level.

Regards,

Kudret

Hi Kudret

1) Does Vcc=3.3V?

2) Since I have 16 ADCs on my board , and only 1 HMC, I don't want to route 3.3V plane to all matching networks (which are located close to adc input).

Can I use one of the ADC supplies for Vcc (1.8V_DRVDD for example), if yes, what should be resistors values?

Thanks Barak

Hi,

Yes, Vcc is 3.3V as it is the supply voltage of driver. Unfortunately, 1.8V is not an option because output of the driver is around 2.1V. 

It is suggested to put the resistors close to receiver side in general. If the distance between the HMC7044 and the ADC is not too much, you can place the resistors close to driver side. Another option is to put first resistor to driver side and the other two close to receiver side. 

Regards,

Kudret

Hi,

Yes, Vcc is 3.3V as it is the supply voltage of driver. Unfortunately, 1.8V is not an option because output of the driver is around 2.1V. 

It is suggested to put the resistors close to receiver side in general. If the distance between the HMC7044 and the ADC is not too much, you can place the resistors close to driver side. Another option is to put first resistor to driver side and the other two close to receiver side. 

Regards,

Kudret

Hi,

Does the same termination relevant for ADCLK948 as sysref driver (instead of HMC)?

Any answer?

I don't know if ADCLK948 is used as SYSREF driver. It would be better to create another post for it.

Kudret