XTR111: Design Review

Hi Subhash,

Sure! You need to send over the schematic and layout if you have them. 

Best Regards,

Robert Clifton 

Hi Robert Clifton,

Attaching the Schematic for review 

What is the purpose of C134? A capacitive load of 100000 pF will make the OPA145 oscillate (see figure 6.27). Do you think that the DAC or the opamp will add noise?

Hi Clemens,

We have placed CAP C134 to suppress the noise. It can be made DNI during testing.

Thanks 

Subhash R

What noise? If you expect noise, why don't you filter the opamp's input?

Hi Subhash,

I have a few additional questions to add:

• What is the expected in put voltage range on the input of the XTR111? 
  • Right now my calculations suggest you are wanting have a Vin = 0.6V to get 4mA and Vin = 3V to get 20mA.
• Are you planning on using the XTR111's voltage regulator to power any external circuitry?
  • I don't see any connected to it.

Best Regards,

Robert Clifton 

Hi Robert ,

• What is the expected in put voltage range on the input of the XTR111? 
  • Right now my calculations suggest you are wanting have a Vin = 0.6V to get 4mA and Vin = 3V to get 20mA.: - Yes that's Correct 
• Are you planning on using the XTR111's voltage regulator to power any external circuitry?
  • I don't see any connected to it: - XTR11 output is connected to a header to connect the external sensor. 

Thanks 

Subhash R

Hi Clemens,

The Cap C134 is the decap for XTR111.

Thanks 

Subhash R