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Original question:

TCA9617B: Can we connect the I2C master to VCCB side and Slave to VCCA side?

TCA9617B: TCA9617B

Emil D
Prodigy 20 points
Part Number: TCA9617B

I need that the I2C voltage translator buffer works on the following conditions:

FPGA (Master) side:  3.3V or 2.5V.

Slave side: 1.8V or 2.5V or 3.3V or 5V. Only one at a time.

Frequences: 100Khz or 400Khz or 1 Mhz.

I will control the clock and the Voltage on the slave side, and choose one of the

mentioned above clocks and voltages.

I have only one slave at a time.

I'll be glad to have any suggestion of how choose pull up resistors. Should they be 820 ohm ?

  • 0
    TI__Guru 73971 points

    Emil,

    We only have one I2C Buffer that supports 1Mz so we don't have too many options here. If you want to support all those voltages, then you may need to set up two TCA9617B's in parallel and disable one when the other is in use. The Rule we need to follow here is that VccB should be greater or equal to VccA while still meeting the Vcc restrictions.

    For the pull up resistor, we will need to know the expected bus capacitance on both sides. Is it safe to assume this is an onboard communication set up or are you going to use wires to connect to another board?

    -Bobby