We have assembled one board and mounted 5962-9312601MXA (Base part#AD1671) with IC Base.
During the calibration, We are unable tune ADC offset and Gain. When we are feeding ADC input -4.99, offset should be tuned to 000h ~ 007h, But We are getting 1E3 and unable to bring to 000h.
Similarly For +4.99V ADC input, We are getting the FFFh at 3.5V ADC input itself. We have probed the Encoder and DAV pin.
Its seems DAV is coming as pulsed signal ( frequently high and low) when encoder enable. It seems ADC doing again and again the conversion. Please reference attached image reference DAV_Defect_1.jpeg.
Later we are replaced with new ICs and its working fine. We are able to tune the offset and gain. DAV pin also working fine wrt encoder. Attached DAV_working part.jpeg.
Based on that, We have concluded go ahead for assembly of another two boards. We have assembled. then we went particular ADC offset tuning. In this both board while first transaction DAV pin ( frequently high and low) when encoder enable.DAV_Defect_2.jpeg.
Please can some one help me on this. Thanks!
ADC Schematics
