Post Go back to editing

PCB Design for ADMV4420

Category: Hardware
Product Number: ADMV4420

Hi,

i checked the datasheet for suggested PCB layout and found it calls for 50Ohm input CPWG onto 10mil Ro4350B substrate.

Recommended dimensions for 50Ohm line are Width=16mil + Gap=13mil, which in typical CPWG design results in approx. 55/57Ohm depending on grounding, Dk tolerances, etc.

I expected smaller Gap (i.e. 5mil at the same width) to get nominal 50Ohm. Are this extra gap due to device specific tuning (i.e. proper device Zin, residual solder mask, effects of multilayer)?

Can you pls confirm the datasheet dimensions are ok for 10mil Ro4350B CPWG?

Thanks for reply

Parents
  • There are multiple recipes for Ro4350B 10mil substrate thickness.

    Generally, we found that W=16 / G=13 was good with solder mask applied, and 18/13 for no solder mask. The ADMV4420 evaluation board does not have solder mask, as it was designed at an earlier time, so there may be some marginal improvement by changing the width to 18 and not placing solder mask. Datasheet performance was collected with 16/13, so you could expect similar performance in your application.

    Also, another common recipe for narrow pitch pins is W=13 / G=5 mils.

Reply
  • There are multiple recipes for Ro4350B 10mil substrate thickness.

    Generally, we found that W=16 / G=13 was good with solder mask applied, and 18/13 for no solder mask. The ADMV4420 evaluation board does not have solder mask, as it was designed at an earlier time, so there may be some marginal improvement by changing the width to 18 and not placing solder mask. Datasheet performance was collected with 16/13, so you could expect similar performance in your application.

    Also, another common recipe for narrow pitch pins is W=13 / G=5 mils.

Children
No Data