ADS7138-Q1: The principle of I2C ADDRESS setting

Jimmy Chen

Part Number: ADS7138-Q1
Other Parts Discussed in Thread: ADS7138

Dear Sirs,

May I ask why the I2C ADDRESS can be changed by changing R2 even if R1 is DNP? I am curious how it works?

Could you kindly help to describe the principle of setting the I2C ADDRESS by changing the external resistance inside the IC with pictures?

Your assistance will be greatly appreciated.

over 2 years ago

+1 Tom Hendrick over 2 years ago

TI__Guru**** 181521 points

Hi Jimmy,

Basically there is a voltage divider and a comparator internal to the ADS7138. Let's call the internal resistors R1a and R2a. When the external R1 or R2 are installed, they will be in parallel with the internal R1a and/or R2a so that the device can detect eight different voltage levels based on what resistors are or are not installed. Hope that clears things up for you!