frequency of op-amp in bandgap reference

[Azmi]

normally, what the operation frequency of op-amp for bandgap reference design? should we set it just around flicker noise freq (1kHz or 10kHz) or higher (1MHz or 10MHz)?

 

[Blackuni]

Hi,

R u talking about the GBW of the opamp or something else?

if its BW of the opamp, then its compromised based on the gain, performance, current consumption, PSRR, area ... (normally PSRR will get affected @ high freq)

Please correct me if i am misleading.

Thanks,

 

[selvaraja]

depends on your system also. but narmally few kilo hertz will do.

 

[lwjbh]

Phase margin or stability should also be considered

 

[Azmi]

thanks for the response.
However, as we know in bandgap ref, there are no AC signal at the input of op-amp (except difference of voltage). If all the above parameters have been considered, do we need to design the op-amp at higher f3dB (eg. at 10MHz)?
thanks.

 

[Blackuni]

Hi,

it may be the ideal case !! not always its only DC. I believe you agree that.

Upto my knowledge <1Meg does a better job in all aspect(power, area, noise.

Higher BW is not always an advantage.

Can you list out u r specification of BG ref?

Thanks,

 

[elbadry]

Increasing Opamp BW can help improve supply rejection

There is no specific range. It all depends on system specs