How to increase the unity gain bandwidth of a single stage differential opamp?

[analog_adam]

Hi Guys;

I am designing a single stage differential opamp with no cascodes. I currently obtained a unity gain bandwith of 1.25 GHz with 0.18 CMOS process. However, I need to increase this value up to 6-7 GHz. Do you guys know how to increase the unity gain bandwidth of a single stage differential opamp? Thanks for help.

 

[ppenday]

Re: Unity Gain Bandwidth

increase gm

 

[pixel]

Re: Unity Gain Bandwidth

Generally with higher current you can achieve better GBW until you come to some limit.

 

[montage3000]

Unity Gain Bandwidth

increase power

 

[safwatonline]

Unity Gain Bandwidth

GBW equal gm/C so increasing gm and decreasing the o/p cap.

note gm icrease by increasing current and keeping the Veff minimum but keeping it minimum comes by increasing W/L which increase area and hence cap. so optimize.

Added after 56 seconds:

note i considered active loads to neglect the o/p resistance (i.e. ro of th load euqal ro of the diff. pair)