\newcommand\height{2.0}
\draw [] (0, \height/2)                       coordinate (vip) 
   to [short,o-] ++ (1,0)
   to [R,l_=$R_{\mathrm{i}}$] ++ (0,-\height) coordinate (x)
   to [short,-o]                 (x-|vip)     coordinate (vin);

\draw (5.5, \height/2) coordinate (vop)  
     to [short,o-] ++ (-1.25,0) coordinate (rop)  
     to [short,*-] ++ (-2.25,0)
     to [ american controlled current source
        , l=$G_{\mathrm{m}} \cdot \underline{V}_{\mathrm{I}}$
        , -*
        , invert
        ] ++ (0,-\height) coordinate (gnd)
     to [short,-*] (gnd-|rop) coordinate (ron)         
     to [short,-o] (gnd-|vop) coordinate (von);

\draw (rop) to [R,l=$R_{\mathrm{o,p}}$]  (ron);

\node[ground] at (gnd) {};

\path [voltarrow] (vip) edge node [midway,left,inner sep=2pt] 
  {$\underline{V}_{\mathrm{I}}$} (vin);
\path [voltarrow] (vop) edge node [midway,right,inner sep=2pt] 
  {$\underline{V}_{\mathrm{O}}$} (von);

\node[anchor=east] at (vip) {INP};
\node[anchor=east] at (vin) {INN};
\node[anchor=west] at (vop) {O};  