Apologies for the delay.
The AD5338R has a common reference pin. When using the internal reference, this is the reference output pin. When using an external reference, this is the reference input pin. The default for this pin is as a reference output.
If you don't want the trouble of having an internal reference, I would suggest you use the AD5338. It is basically the same part without the internal reference.
No problem, thanks for your response. I think in future we will probably use chip without internal reference as you suggested.
Out of interest though, returning to the original question about the AD5338R, what would happen if at startup when the reference pin is in it's default state (of output), it is tied to 5V? Would this damage the chip?
Just to clarify what I meant on my last reply. The AD5338 (without the reference) is the same as the AD5338R in the following aspects:
They are different in some aspects namely:
Apologies if this has caused any confusion.
To answer your question, there will be a temporary short circuit, the internal die will be heat a little bit, as they try to drive the max current but nothing else, as it will be temporary. This is under the assumption that the reference will be switched from internal to external.