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BQ25700A: BQ25700 hold time violation

Fred Cheng
Expert 5660 points
Part Number: BQ25700A
Other Parts Discussed in Thread: BQ34Z100, BQ25700, BQ25703A

Hi team,

customer use BQ34Z100 and BQ25700 for communication,

but BQ34Z100 is I2C interface,  BQ25700 is SMbus.

looks like they encounter hold time violation,

can I add a capacitor at SDA to slow down the fall time to fit the hold time spec? 

or this is interface problem since they use different interface?

 

  • 0
    TI__Mastermind 32695 points

    1. You may use BQ25703A, which has an I2C interface. 

    2. We seldom add a capacitive load on the DATA and CLK line. I think this is an interface issue. Our charger is a slave device.

  • 0 in reply to Tiger Zhou
    TI__Expert 5660 points

    Hi Tiger,

    Thanks  for your reply,

    but I am still confused since even BQ25703A, the hold time spec is still 300ns,

    and I2C and SMbus are basicly the same  when at 100kHz

    the root cause is still not solved. so I think we still need to do something to fix hold time.

    what's your feedback on this?

  • 0 in reply to Fred Cheng
    TI__Mastermind 32695 points

    Please fix the issue at the host controller. Our charger is a slave device, which means it listens to the host controller command and act. A master device initiates a bus transfer and provides the clock signals. A slave device can receive data provided by the master or it can provide data to the master.