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Regarding AD6688/AD9208 Eval board - AD9208_3000EBZ

Question asked by spraju87 on Oct 27, 2017
Latest reply on Nov 15, 2017 by UmeshJ

Hello,

 

We recently designed a PCB for AD6688/AD9208 ADCs based on the eval board design files of AD9208_3000EBZ. As per ADI, this is the official eval board for AD6688/AD9208. The entire ADC power supply of our PCB was designed based on this eval board schematic (almost a copy paste).

 

However, when we measured the voltages at most test points we see they are 10% higher than necessary. Further, on calculating the actual voltages based on the resistor values used in the AD9208_3000EBZ, we also see that the voltages are 10% higher than required (DRVDD_0P9 is 1V instead of 0.9V, 2V4_AVDD is 2.6V instead of 2.4V,  AVDD_1P8_REG is 2V instead of 1.8V and so on)

 

It would be very helpful if someone could clarify if it was intentional from ADI to design the eval board with 10% higher voltage than specifications? If yes, why was it done ? Is it even safe to operate the ADC at 10% higher values ?

 

Regards,

Raju

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