Mixed-signal decoupling capacitors

[abcyin]

Hi, all,

we are designing a mixed signal chip, somebody told me that there should no on-chip decoupling cap for the digital blocks, which should be decoupled with off-chip capacitors, I am wondering that is this true or false?

What is the right way for such mixed signal chip decoupling?

Thanks in advance,
abcyin

 

[erikl]

I always used otherwise empty space between blocks (if so) for power supply decoupling, be it for analog or digital blocks, too. But I wouldn't dedicate extra silicon area for internal power supply decoupling caps. Too costly.

This is my opinion - may be there are different ones.