|
发表于 2009-11-20 14:32:07
|
显示全部楼层
When you change process, the matching of the devices could get worse and so could the variance of your bandgap output. For higher delta_beta/beta and/or higher delta_vth, you will have to increase your mosfet device sizes to reduce offsets. The first order result of the offset voltage of each transistor is about (Vgs-Vth)/2*(delta_beta/beta)-delta_Vth, and you could refer the contribution of each transistor back to the opamp input to get the opamp offset. Therefore, you could decide the minimum devices size required. |
|