Very new to EDA and PCB work so please bear with me. Implementing the circuit in the image and clueless as to the value of the three resistors connected to VDD and IRQ / SCL / SDA. The datasheet provided by NXP for the MPR121 doesn't explain why you would attach them.

 

hi cyth,
Welcome to AAC.
This PDF should help you determine the Pull-Up resistor values for your circuit.
Ask if you have a problem.
E

 

Those resistors are pullups for I2C SCL and SDA, and /IRQ.

The data sheet does mention 4.7k resistors for the I2C pins, and the same value or 10k should work for /IRQ.

 

Ah, I see. Thank you!

 

The I2C pullups are somewhat critical.

The /IRQ pullup up to 10K will be fine.

The is a 3.3 volt part, so you'll need level shifters if using a 5v micro.