Aurix TC377x Analog Input Impedance

[KS_Nguyen]

Hi Community,

Hi Infineon Team,

What is the input impedance for analog-input pins AN16 and AN18  of the Aurix TC377TB-96F300S AA ?

I didn't find information about it in the datasheets

Infineon-AURIX_TC3xx_Part1-UserManual-v02_00-EN

Infineon-AURIX_TC3xx_Part2-UserManual-v02_00-EN

Are there Application Notes  / additional resources on Infineon website about analog-input of Aurix controllers?

My goal is to use these pins to connect to a voltage divider and measure voltage divided from a 24V power supply. Current draw from the 24V supply should be 100mA. Thus I like to know the input impedance, so I can calculate the value for R6 for the case that 24V corresponds to a 2.5V signal input an AN18 like the attached picture shows.

Thank you for your time and have a great weekend!

Sebastian.

[KS_Nguyen]

Actually my problem with the circuit got solved, R6 = 25Ohm

But still, where can I find Information about the analog-inputs of the controller?

[MoD · Accepted solution]

Please see Figure 3-2 Equivalent Circuitry for Analog Inputs, there you can find equations for calculation based on values from Table 3-21.

[Di_W]

In the AURIXTC3XX_UM_PART2_V2.0.PDF, you can check 32.16 Electrical Models, there is a Calculation Example also for input impedance Z(AIN)