adix
Junior Member level 2
Hi all,
I am designing a telescopic ota with SC-CMFB. These are my design specs:
vdd=1.8V
gbw=500MHz
load=100fF
DC gain>40db
My design works well with an ideal CMFB. My problem is the design of the SC-CMFB. I read the paper of Choksi and also several books. Once i connect the SC-CMFB to my OTA, the DC gain drops. Furthermore, the CM output is not the one I set. Any tips on designing the SC-CMFB or errors you think I may have done?
![](https://obrazki.elektroda.pl/35_1305648944_thumb.png)
I am designing a telescopic ota with SC-CMFB. These are my design specs:
vdd=1.8V
gbw=500MHz
load=100fF
DC gain>40db
My design works well with an ideal CMFB. My problem is the design of the SC-CMFB. I read the paper of Choksi and also several books. Once i connect the SC-CMFB to my OTA, the DC gain drops. Furthermore, the CM output is not the one I set. Any tips on designing the SC-CMFB or errors you think I may have done?
![](https://obrazki.elektroda.pl/67_1305648944_thumb.png)
![](https://obrazki.elektroda.pl/35_1305648944_thumb.png)