\documentclass[border=0mm]{standalone}

\usepackage{cmap}
\usepackage[cp1250]{inputenc}	
\usepackage[T1]{fontenc}
\usepackage{graphicx}
\usepackage{lmodern}
\usepackage{tikz}
\usepackage{float}
\usepackage{siunitx}
\usepackage{amsmath}
\usepackage{upgreek}
\usepackage{pgfplots}
\pgfplotsset{compat=1.17}
\usepgfplotslibrary{fillbetween}
\usepgfplotslibrary{units}
% \makeatletter
%\pgfplotsset{
%  unit code/.code 2 args=
%    \begingroup
%    \protected@edef\x{\endgroup\si{#2}}\x
%} 
%\makeatother

\pgfkeys{%
  /tikz/on layer/.code={
    \pgfonlayer{#1}\begingroup
    \aftergroup\endpgfonlayer
    \aftergroup\endgroup
  }
}

\begin{document}
	\begin{tikzpicture}
		\begin{axis}[
			height=7cm,	width=11cm,	grid=major,
    		x unit=\SI{}{\degreeCelsius}, y unit=\SI{}{\mega\hertz},
			xlabel=Temperature,	ylabel={$f_\mathrm{0}$},
			ymin=550,ymax=700,
			xmin=-45, xmax=130,			
			ytick distance = 25,
			xtick = {-45,-25,0,25,50,75,100,130},
			set layers,
			y tick label style={/pgf/number format/.cd, set thousands separator={}},
			xticklabel shift = 2 pt,
			legend pos=north west,
			 /pgf/number format/.cd,
            fixed,
            precision=3,
        /tikz/.cd
		]			

\addplot +[solid, smooth,thick,color=red,mark=none] table [x expr=\thisrow{temp}, y expr=\thisrow{cc_1v2}*1e-6, col sep=comma] {../cadence_data/f0_wo_dll_vt.csv};
			\addlegendentry{CC bias};	
			
			\addplot +[solid, smooth,thick,color=blue,mark=none] table [x expr=\thisrow{temp}, y expr=\thisrow{dll_1v2}*1e-6, col sep=comma] {../cadence_data/dll_freq_nomR.csv};
			\addlegendentry{DLL bias};		
			
			\addplot +[name path = dll_1v08,solid, smooth,thick,color=blue,mark=none, draw=none] table [x expr=\thisrow{temp}, y expr=\thisrow{dll_1v08}*1e-6, col sep=comma] {../cadence_data/dll_freq_nomR.csv};
			\addplot +[name path = dll_1v32,solid, smooth,thick,color=blue,mark=none, draw=none] table [x expr=\thisrow{temp}, y expr=\thisrow{dll_1v32}*1e-6, col sep=comma] {../cadence_data/dll_freq_nomR.csv};
			
			\addplot +[name path = cc_1v08, solid, smooth,thick,color=red,mark=none, draw=none] table [x expr=\thisrow{temp}, y expr=\thisrow{cc_1v08}*1e-6, col sep=comma] {../cadence_data/f0_wo_dll_vt.csv};
			\addplot +[name path = cc_1v32,solid, smooth,thick,color=red,mark=none, draw=none] table [x expr=\thisrow{temp}, y expr=\thisrow{cc_1v32}*1e-6, col sep=comma] {../cadence_data/f0_wo_dll_vt.csv};
			
			\addplot[red, fill opacity = 0.2] fill between[of=cc_1v08 and cc_1v32];
			\addplot[blue, fill opacity = 0.2] fill between[of=dll_1v08 and dll_1v32];
			
			\draw [<->,color=red!60!black] (axis cs:100,648) -- node[left, pos = 0.77, color=red!60!black]{$\pm 10\%\: V_\mathrm{DD}$ variation} (axis cs:100,675) ;
			
		\end{axis}
	\end{tikzpicture}
\end{document}