winsonpku
Advanced Member level 4
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I have taped out a bandgap circuit and the test results shows that the bandgap is failed.
Test reports show that the bandgap drifts about 200mV on one wafer
i mean test all dies on one wafer, the voltage drift about 200mV.
The bandgap is amp based.
the amp is a two stage amp, the first stage is folded-cascode and the second stage is a simple drive stage, current source load stage. Pmos is the drive stage.
The current flows the two bipolar is about 2.5uA seperately
and the amp consumes about 6uA current
so what is the problem about my bandgap?
The simulation results of my bandgap shows it could work properly
please help me and any advice is welcom!
![Crying :cry: :cry:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Crying :cry: :cry:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Crying :cry: :cry:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Crying :cry: :cry:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Crying :cry: :cry:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![Crying :cry: :cry:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Test reports show that the bandgap drifts about 200mV on one wafer
i mean test all dies on one wafer, the voltage drift about 200mV.
The bandgap is amp based.
the amp is a two stage amp, the first stage is folded-cascode and the second stage is a simple drive stage, current source load stage. Pmos is the drive stage.
The current flows the two bipolar is about 2.5uA seperately
and the amp consumes about 6uA current
so what is the problem about my bandgap?
The simulation results of my bandgap shows it could work properly
please help me and any advice is welcom!