Junus2012
Advanced Member level 5
Dear Friends,
I finished with the design of single ended OTA. the GBW was achieved is 20 MHz by driving capacitive load of 10 PF. Now I chnaged the design to fully differential OTA and I kept exactly the same biasing current or circuit transistor ratios, then I connected the smae load of 10 PF differentially between the two outputs to make a comparesion between the single and fully differential amplifier performance, I have found that differential amplifier is loosing half of the GBW ( =10MHz).
This leads me to reinvistigate the formula of GBW = gm1/2 pi CL for single ended,,, does it mean that GBW = 2gm1/2 pi CL for fully differential ampliifier ?
Or you have different explanation for this case
Thank you
I finished with the design of single ended OTA. the GBW was achieved is 20 MHz by driving capacitive load of 10 PF. Now I chnaged the design to fully differential OTA and I kept exactly the same biasing current or circuit transistor ratios, then I connected the smae load of 10 PF differentially between the two outputs to make a comparesion between the single and fully differential amplifier performance, I have found that differential amplifier is loosing half of the GBW ( =10MHz).
This leads me to reinvistigate the formula of GBW = gm1/2 pi CL for single ended,,, does it mean that GBW = 2gm1/2 pi CL for fully differential ampliifier ?
Or you have different explanation for this case
Thank you