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TMP451-Q1: Schematic Review

user4979899
Expert 3080 points
Part Number: TMP451-Q1
Other Parts Discussed in Thread: PCA9306, TMP451, SN74AVC4T245

Hi Sir,

Could you please help on the TMP451-Q1 schematic review as below?

Thanks

  • 0
    TI__Guru* 91086 points

    Dear Anne - 

    I don't see pullup resistors on the I2C bus lines. Looks like these are two different I2C channels. Also looks like the devices are running off two separate voltage rails. Is that correct? (top one is running from 1.8VDC and bottom is on 3.3? 

    if its same MCU, can it handle that, or do you need level translator like PCA9306 for top device? 

  • 0 in reply to Josh Wyatt
    TI__Expert 3080 points

    Hi Josh,

    Please see below my feedback as red.
    Let me know if there is any questions.
    Thanks

    I don't see pullup resistors on the I2C bus lines.→ See the renewed PDF “ TMP451_20190612 ”

    Looks like these are two different I2C channels. → Yes

    Also looks like the devices are running off two separate voltage rails. Is that correct? (top one is running from 1.8VDC and bottom is on 3.3?
    if its same MCU, can it handle that, or do you need level translator like PCA9306 for top device?
    → Yes, two device are running off two separate voltage rails, and we use SN74AVC4T245 for top device already.

    TMP451_20190612.pdf

  • 0 in reply to user4979899
    TI__Guru* 91086 points

    Anne - 

    thanks - i meant level shifter on the I2C lines, but maybe their MCU can handle it. 

  • 0 in reply to Josh Wyatt
    TI__Expert 3080 points

    Hi Josh,

    OK,I got your point. The two I2C are from different MCUs. Besides, could you please help to provide the check list for this. It will be very useful for our future design. Thank you.