hi All,
My customer uses I2C function ( pin19 & pin20 ) on UCD3138128.
Customer has some chips on hand, only one chip has weird I2C waveform as right side. ( left side is normal wave form )
Customer uses 10Kohm pull-up resistor and 22pF filter for all chips. ( see below circuit )
Customer can't find any recommend pull-up resistor, and can't find any electrical characteristics about input capacitance of pin19 & pin 20 ( I2C_CLK & I2C_DATA ) on spec.
Customer want to know exactly the electrical characteristics of I2C function on UCD3138128, please reply these questions from design team, many thanks.
The questions as below :
1. What is the recommend pull-up resistor range (1k-10k?) for UCD3138128 I2C function?
2. What is input capacitance spec of pin19 & pin 20 ( I2C_CLK & I2C_DATA ) ?
3. Does the chip with weird waveform has bigger input capacitance than other chips on pin19 & pin20, it caused I2C communication failed?