I2C Bus extender P82B715

[ashno_james]

Hi All,

We are using P82B715 for connecting multiple slaves with one master MCU to compensate Bus capacitance ( in certain cases we have to connect upto 16 slaves, and we have to go with same design for MCU board , that is why we are using Bus Extender). In our case GND will be same for both Slave PCB board and Master ( MCU) PCB board. But the power supply generated for both boards are from different sources of same voltage output  levels (5V).  Sample Schematic attached.

Can you please comment on this power supply scheme, whether it is OK or not for proper I2C communication functionality ( speed is 100KHz)?

And How about two slaves in the slave PCB board which shares the Sx,Sy lines  ( SDATA, SCLK) and is pulled up to different power supply's  ( one LDO and a Buck regulator) of same voltage output (5V), and sharing common GND.

Thanks& Regards

[reyes · Accepted solution]

Since the voltage level is the same, you should not have any communication issue using this configurations, otherwise, you would need to use a logic level shifting by using an external transistor as in Figure 10 of the App Note AN10710: https://www.nxp.com/docs/en/application-note/AN10710.pdf.