Align TikZ node inside equation environment

Align TikZ node inside equation environment References I am trying to insert a TikZ node into an equation but I have some problems: the = sign is not vertically centred inside the circle the circle is not vertically aligned with the formula. I want to abtain the same alignment of the first equation but I failed also using the baseline option the equal sign must be at same distance from ) as in the first equation SOLUTIONS UNSOLVED Solved in comments using baseline=-\\the\\dimexpr\\fontdimen22\\textfont2\\relax UNSOLVED \\documentclass{article} \\usepackage{amsmath} \\usepackage{tikz} \\newcommand{\\mathnodebase}{% \\tikz[inner sep = 0pt,baseline]{\\node[circle,draw=black] (1) {$=$};}} \\newcommand{\\mathnode}{% \\tikz[inner sep = 0pt]{\\node[circle,draw=black] (1) {$=$};}} \\begin{document} \\begin{equation} \\prod_{z^n=-1}(w_1(z)^n+1) = \\end{equation} \\begin{equation} \\prod_{z^n=-1}(w_1(z)^n+1) \\mathnodebase \\end{equation} \\begin{equation} \\prod_{z^n=-1}(w_1(z)^n+1) \\mathnode \\end{equation} \\end{document}