fold-cascode opamp ac simulation in Hspice

I&nbsp;overleaped&nbsp;the&nbsp;netlist&nbsp;here.........following&nbsp;is&nbsp;the&nbsp;controlled&nbsp;description.<br /><br />------------------------------------<br /><br />V_VSA&nbsp;vsa&nbsp;0&nbsp;DC=0<br />V_VDA&nbsp;vda&nbsp;0&nbsp;DC=3<br /><br />V_vip&nbsp;vip&nbsp;0&nbsp;DC=1<br />I_IIN&nbsp;0&nbsp;iin&nbsp;DC=2.5uA<br />v_vim&nbsp;vim&nbsp;0&nbsp;1&nbsp;AC=1&nbsp;&nbsp;&nbsp;$&nbsp;ac&nbsp;source<br />R_AC_COUPLE&nbsp;vim&nbsp;vimz&nbsp;1e9&nbsp;ac=0&nbsp;&nbsp;&nbsp;.<br /><br />R_self-bias&nbsp;vout&nbsp;vimz&nbsp;1m&nbsp;ac=1e30&nbsp;&nbsp;&nbsp;&nbsp;<br /><br />c_load&nbsp;vout&nbsp;vsa&nbsp;cval&nbsp;&nbsp;$&nbsp;varying&nbsp;load&nbsp;capacitance<br />.TEMP&nbsp;25<br />.options&nbsp;nomod&nbsp;numdgt=6&nbsp;acout=0&nbsp;runlvl=0&nbsp;accurate&nbsp;post&nbsp;probe<br />.prot<br />.lib&nbsp;'mm06.l'&nbsp;tt&nbsp;&nbsp;&nbsp;&nbsp;<br />.unprot<br /><br />.op<br />.param&nbsp;cval=0<br />.AC&nbsp;DEC&nbsp;10&nbsp;1m&nbsp;10MEG<br />.print&nbsp;AC&nbsp;vdb(vout)&nbsp;vp(vout)&nbsp;v(*)<br /><br />.alter<br />.param&nbsp;cval=1p<br /><br />.alter&nbsp;<br />.param&nbsp;cval=10p<br /><br />.alter<br />.param&nbsp;cval=100p<br /><br />.end<br /><br />----------------------------------------------<br /><br /><br /><br />I'm&nbsp;fresh&nbsp;,pls&nbsp;see&nbsp;my&nbsp;questions&nbsp;below:&nbsp;<br /><br />1,Through&nbsp;viewing&nbsp;the&nbsp;phase&nbsp;waveform,it&nbsp;has&nbsp;two&nbsp;turnings,whether&nbsp;means&nbsp;it&nbsp;has&nbsp;2-pole&nbsp;response?and&nbsp;how&nbsp;did&nbsp;you&nbsp;calculate&nbsp;it?<br /><br />2,How&nbsp;does&nbsp;change&nbsp;in&nbsp;load&nbsp;capacitance&nbsp;affect&nbsp;pole&nbsp;location(s)?<br /><br /><br /><br />Need&nbsp;your&nbsp;helps,&nbsp;thanks&nbsp;in&nbsp;advance!<br /><br /><br /><br /> 相关链接:<a href='http://bbs.21ic.com/upfiles/img/20078/20078131293610.rar'>http://bbs.21ic.com/upfiles/img/20078/20078131293610.rar</a>

schematics

test&nbsp;method