Help needed: The PSRR of Bandgap various with temperature?

[scutlan]

hello everyone~

Here is the simulation result of a bandgap which I am degisning. the structure is the commonly used low voltage bandgap proposed by Banba.
The PSRR of Bandgap various with temperature in every MOSFET corners(TT FF SS...)

temp= -20 PSRR= -34db
temp= 0 PSRR= -42db
temp= 20 PSRR= -55db
temp= 40 PSRR= -51db
temp= 60 PSRR= -43db
temp= 80 PSRR= -39db

I have observed the Op Amp used in this bandgap, it works well (gain over 60db in every temp&MOSFET corners).

how to improve the PSRR of the bandgap?

Thank you ~~
Need ur help~

:|

 

[gevy]

Re: Help needed: The PSRR of Bandgap various with temperatur

hello everyone~

how to improve the PSRR of the bandgap?

:|

To increase Gain of Op Amp.

 

[babbage]

if just dc psrr, yes to increase the loop gain is one method because close-loop psrr is equal to open-psrr devide to open-loop gain.

Added after 2 minutes:

According to the previous theory, there both sides to incease the psrr: one is to use the high-psrr structure; other is to incease the loop gain , of cource mainly opamp;

 

[scutlan]

Re: Help needed: The PSRR of Bandgap various with temperatur

thank you gevy & babbage~~

yes , for increase the dc psrr of bandgap can be done by increase the opamp gain.

but,,,my question is why the dc psrr various with temperature,,while the opamp gain does't various.