Help me with my circuit - Bandgap reference

[crazy4analog]

Band gap reference

I designed a Bandgap reference to have a Zero Temp co at Room temp (25 deg C). I get 1.2V at 25C, however, the plot of Vref and temp does not look correct. Also, i plotted d(vref)/dT, and at any temperature it does not cross 0.

I am attaching a copy of my schematic, plot o fVref Vs Temp and the temp co.

Can someone please help me in what is wrong with the circuit?

 

[crazy4analog]

Re: Band gap reference

Can someone please help me on this?

 

[edge_tv]

Band gap reference

Play with the resistor. The resistor sets the amplification of the PTAT Voltage. Means you can move the maximum of the Bandgap refrence (Vbe-V_PTAT=Vbg). Normal people set the maximum of the Vbg voltage to 27 C°. You can do a parametric simulation (with Rpn as paramtere) you should see the maximum move over temp