With PDF Timestamp Signer, we can create Timestamp signature on a PDF without the need of Adobe Acrobat.
You can download it from here.
This version has some limited,

• It only support create visible signature, and put the signature on the left bottom corner(100, 100, 300, 200) of the first page.
• It use http://tss.pki.gva.es:8318/tsa as timestamp server
• It only supports PKCS12 certificate file.
• It run as windows 32 console application, so it has no windows, and only run in Dos command

pstoedit+ghostscript
1.download the last version pstoedit and ghostscript
2.install pstoedit and ghostscript
3 run command pstoedit -f dxf in.pdf out.dxf(make sure pstoedit can find the path of gswin32c.exe)

pstoedit+gsview
1.download the last version pstoedit and gsview
2.install pstoedit and gsview
3. use pstoedit as a plugin of gsview

pstoedit is a tool converting PostScript and PDF files into various other formats suported by different drawing editors. As a prerequesite it needs GhostScript to be installed (binary installation is sufficient).

Currently pstoedit can generate the following major formats:

• Tgif .obj format (for tgif version >= 3)
• .fig format for xfig
• pdf – Adobe’s Portable Document Format
• gnuplot format
• Flattened PostScript (with or without Bezier curves)
• DXF – CAD exchange format
• LWO – LightWave 3D
• RIB – RenderMan
• RPL – Real3D
• Java 1 or Java 2 applet
• Idraw format (in fact a special form of EPS that idraw can read)
• Tcl/Tk
• HPGL
• AI (Adobe Illustrator) (based on ps2ai.ps – not a real
  pstoedit driver – see notes below and manual)
• Windows Meta Files (WMF) (Windows  only)
• Enhanced Windows Meta Files (EMF) (Windows, but also Linux/Unix if
  libemf is available)
• OS/2 meta files (OS/2 only)
• PIC format for troff/groff
• MetaPost format for usage with TeX/LaTeX
• LaTeX2e picture
• Kontour
• GNU Metafile (plotutils / libplot)
• Skencil ( http://www.skencil.org)
• Mathematica
• via ImageMagick to any format supported by ImageMagick
• SWF
• CNC G code
• VTK files for ParaView and similar visualization tools

From above cheat, we know pstoedit supports generate DXF, but it needs the help of Ghostscript or GsView

Ghostscript is the name of a set of software that provides:
* An interpreter for the PostScript (TM) language and the Adobe Portable Document Format (PDF — sometimes confused with Acrobat, Adobe’s PDF browser/editor product), and
* A set of C procedures (the Ghostscript library) that implement the graphics and filtering (data compression / decompression / conversion) capabilities that appear as primitive operations in the PostScript language and in PDF.

reference,
GPL Ghostscript
GSview
pstoedit

After the first release, I found a bug of jbig2.exe,
when I tried
jbig2.exe -p 1.tiff>1.jbig2
I found the created jbig2 file under Windows is bigger than under Linux, and after check, it is not correct jbig2 file.
After some efforts(sorry for my poor c/c++ and python), I fixed the bug.

P.S.
Change logs of this release

*pdf.py create correct PDF to stdout under windows
for details, please visit How to Let Python Send Binary data to stdout under Windows
*fix a bug, that jbig2.exe -p can not get the correct content, also stdout issue.