Is there any data of the "switching input current" (related to the offset stabilizer) of this device?
This current with my 2 x 4.99K source resistance seem add a input offset error
If you are referring to the input bias current of the device, figure 17 on the datasheet should be useful for you:
If this is not the data that you need, could you provide more information on your circuit? What is the value of the offset that you're seeing?
Actually I am not sure if this is the cause of the problem
Attached is the schematic for this application
This is a RTD conditioning amplifier
If I remove CA4, DOUT of the amplifier goes to +VCC
The gain is set to 13.229 V/V
I am trying to understand what the internal switching network of this device
Fausto Bartra, PEng
Tekran Instruments Corp.
330 Nantucket Boulevard
P: 416-449-3084 x 287
With the current source and RTD connected, what output are you seeing? Is there a reason that you are removing CA4 from your circuit?
The only scenario I can think of to explain what you're seeing is when the RTD is not connected to your inputs. It is possible that leakage currents are charging up parasitic and reverse diode capacitances, causing the output to rail to Vcc. Could you elaborate more on what you are getting on your bench setup?
I think I found the problem
Appears to be on the current source that is causing the error
Retrieving data ...