The current of the AD7682's external reference

Hi licunxu ,

It is stated that it has a 50 uA typical rating for its current when external supply is used.

On the other hand, you need also to take note on these key points to be able to optimize the device when external reference is used. Also, as long as your chosen device for the external reference is within the specs of the suggested parts, then the device will be in its optimal state.

Warm regards,
Jo

Thank you

Hi

If I don't use the input IN3 or IN4, what do I need to deal with it, whether it's float or grounded with a 0Ω resistor

Hi licunxu ,

I recommend tying these pins to ground with a high value resistance (around 10k). It is a best practice to not leave any unused pins as it may induced instability to the output of the device. 

Warm regards,
Jo

Hi Jo，

Is the reference ground for VIO analog GND or digital DGND?

Hi licunxu ,

Based on its current datasheet and user guide, I think having them in a common ground plane would be fine. Are you going to create a custom board using this device?

Regards,
Jo

Hi Jo

Yes，I will use AD7682 in my sch

HI licunxu ,

May I know your specific application? Having two (2) different ground planes also depends on application. But I suggest following the datasheet and user guide.

But you can also try using these links as your reference:

- Microsoft Word - EDch 12 pc issues.doc (analog.com)

- Staying Well Grounded | Analog Devices

Thank you and regards,
Jo

Hi Jo

Thank you for your suggestion.

My application is temperature sensing. The temperature is detected by detecting the voltage of the thermistor.