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Original question:

LM96163: SMBus Timing

LM96163: Clock Time Spec

Allan Fan
Expert 7620 points

Part Number: LM96163
Other Parts Discussed in Thread: AMC6821

Tool/software:

Hi expert,

Customer used LM96163 with SoC which could only provide 3.573Khz SMBus clocking but our DS spec required 10-100Khz. 

Although so far during evaluation stage, customer didn't see any issues. Is it ok still to use the 3.573K SMBus clock frequency?

By the way, is it possible to have linear fan control for rpm adjustment between different set points? 

Regards,

Allan

  • 0
    TI__Expert 7620 points

    Hi experts,

    May I have your help to have a look the questions for customer? 

    Thanks,

    Allan

  • 0
    TI__Mastermind 45455 points

    LM96163 has SMBus Timeout, which will require transactions to complete within the ~30ms timeout specification. If the transaction takes too long, it will be discarded. For an 8 bit register map like LM6163's, there should not be a transaction longer than about 3*9 clock cycles (address, pointer, data.) That would mean the lowest frequency that could still comlete this transaction in 25ms would be nearly 1kHz. (25e-3/(3*9))^-1 = 1.08e3

    AMC6821 has a TACH-PWM feedback loop, which allows the user to configure RPM directly. That may be the feature you are looking for.

    thanks,

    ren