The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Analog Design >> UGB and GBW
https://designers-guide.org/forum/YaBB.pl?num=1264679815

Message started by Abdul on Jan 28^th, 2010, 3:56am

Title: UGB and GBW
Post by Abdul on Jan 28^th, 2010, 3:56am

What is the difference between UGB and GBW. For a single pole system I hope both will be same. If an amplifier has a UGB f1 and if it is cascaded with another amplifier , will there be any relation between the UGB of the resulting system and the UGB's of individual systems

Title: Re: UGB and GBW
Post by tzg6sa on Jan 28^th, 2010, 5:08am

UGB: the frequency where the gain becomes unity
GBW: the product of the 3dB bandwidth and the 3dB frequency.

In the case of a -20dB/dec roll-off the GBW will give the UGB. GBW easier to design for and it is used for an estimation for UGB.
If the dominant pole of the second amp is higher than f1, than the UGB will not change. If not it would be smaller.

The math is easy, try it to work out for better understanding.

Title: Re: UGB and GBW
Post by raja.cedt on Jan 28^th, 2010, 7:01am

hi for a system UGB is independent of the input and output, where as GBW is depends on where you have given input. Take an opamp based inverting amp with gain 5 and non inverting with gain five and calulate ...you feel the difference.

Thanks,
Rajasekhar.