\newcommand\height{2.0}

\draw (0, 0) coordinate (vdsp)  
   to [short,o-,i_=$\underline{I}_{\mathrm{D}}$] ++ (-1.25,0) coordinate (rop)  
   to [short,*-] ++ (-2.00,0)
   to [ american controlled current source
      , l=$g_{\mathrm{m}}\underline{V}_{\mathrm{GS}}$
      ] ++ (0,-\height) coordinate (x)
   to [R,l=$g_{\mathrm{m}}$]  ++ (0,-\height) coordinate (y)
   to [short,-*] (y-|rop) coordinate (ron)
   to [short,-o] (y-|vdsp) coordinate (vdsn);

\draw (rop) to [R,l=$g_{\mathrm{DS}}$]  (ron);

\draw (x) to [ short
             , *-o
             , i_<=$\underline{I}_{\mathrm{G}}\equal0$
             ] ++ (-2.00,0) coordinate (vgsp);

\draw (y) to [short,*-o] (vgsp|-y) coordinate (vgsn);

\path [voltarrow] (vgsp) edge node [midway,left,inner sep=2pt] 
    {$\underline{V}_{\mathrm{GS}}$} (vgsn);
\path [voltarrow] (vdsp) edge node [midway,right,inner sep=2pt] 
  {$\underline{V}_{\mathrm{DS}}$} (vdsn);

\node[anchor=west] at (vdsp) {D};
\node[anchor=west] at (vdsn) {S};
\node[anchor=east] at (vgsp) {G};
\node[anchor=east] at (vgsn) {S};