Hi Derek,
CA server is used to issue certificates for clients. For the detailed information about the certificate requirement of Lync, please try the Lync forum.
>>Does this have to be setup on a domain controller or any member server?
If we use a workgroup server to host CA server, we can only build it as a stand alone server, which means that the template is not available.
>>Does it need to be on the same Server OS version as Active Directory?
No.
>>also does anyone have a good tutorial on how to perform this?
Here is a step-by-step guide about how to setup a CA server:
https://technet.microsoft.com/en-us/library/cc772393%28v=ws.10%29.aspx?f=255&MSPPError=-2147217396
Best Regards.