... download and install PDFin pdf to dwg converter as the AutoCAD add-in ... can help you convert dwg to pdf well.
We can try some freewares such as zamzar, and some best free pdf converter mac.
... you convert PDF files to DWG format. For example, you may try PDF to DWG Converter ... about the program at http://pdf-to-dwg-converter.software.informer.com/
