Hi Team,
I'm planning to use the ADuCM355 and perform measurements using the 4-wire impedance method.
My electrode configuration will be:
-
CE0 for HSDAC output
-
AIN1 for HSTIA input
-
AIN2 and AIN3 for voltage measurement
When using the internal RTIA, I just need to close the T2 switch (AIN1) and T9 switch, while keeping T10 and T11 open.
However, if I use an external RTIA, I understand that I need to use AIN1 and DE0 as part of the HSTIA feedback loop.
So, as far as I understand:
-
Close T2 and T9 switches, and set HSRTIACON[3:0] = 0xF (to disable internal RTIA).
-
Connect the external RTIA between AIN1 and DE0.
-
To complete the feedback loop, set DE0RESCON = 0x97, which shorts both Rload3 and RTIA2_03.
-
Then, the feedback loop should be formed as expected.
However, in the ADuCM355 Hardware Reference Manual, it states to close T1 (AIN0) and T10 switches, which results in a different feedback path.
I’m confused about why the T10 switch needs to be closed in that configuration.
Could you please clarify this point?
I would greatly appreciate your help with this final question.
Best regards,
Anzinc.
