can MC34708's I2C drive on 3.3V instead of 1.8V (1V8_SW5)?

[ronak123]

Hi,

    I am working on i.MX53 board designing. I am using I2C1(3.3V) to drive components on board. I2C2 pads are used for FEC and SD card. Now have only I2C3 pads which can be used to drive  MC34708 on voltage level 3.3V only. But  in datasheet, MC34708 is recommended to drive I2C (SPIVCC) on 1.8V by SW5 (Table 7). And it's rise and fall time is give for SPIVCC=1.8V only. As maximum operating range for SPIVCC is 3.6V, can I drive MC34708's I2C on 3.3V? And is there issue in power sequencing or any other modules for the same?

Or else I have to use voltage level converter for I2C bus?

Thanks,
Ronak.

[TheAdmiral]

Hi Ronak,

The note in Table 7 says typically connected to SW5. You can connect SPIVCC to a 3.3V source and follow the directions of section 7.9.2 for using the SPI CLK and MISO pins for SCL and SDA. The pin CS should be tied to VCOREDIG and the pin MOSI should be tied to either VCOREDIG or GND as desired. Electrical characteristics are shown in Table 120 of section 7.9.3.