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Inquiry regarding Input Register of DAC101S101

Atsushi Okui
Genius 4015 points
Other Parts Discussed in Thread: DAC101S101

Hello, all

Now we have some inquiries regarding Input Register of DAC101S101 from our customer.

Please refer to the items below, and feedback us with your comment.

On this Input Register, there are 2 bits which determines the mode of operation.

In addition to the information on the datasheet, please let us clarify;

Could DB13 and DB12 be enforced to some fixed value in case power supply voltage was dropped below 2.7V?

If so, could you please let us know the value these are enforced to?

If not, do you have any idea to fix these into "11 (high impedance)"?

We thank you in advance for your information.

Best regards,

  • 0
    TI__Genius 16890 points

    Hello,

    The register will keep the values written to it until the supply voltage is dropped low enough (some point below 2.7V) to cause a power on reset.  Once you get to the point where a power on reset occurs, the values in the register will all be set to zero.

    This is different than putting the part in a power down mode.  If you put it in power down mode it will keep the values in the register until you write to it and bring it out of power down mode.

    Mike

  • 0 in reply to Michael Stout
    Genius 4015 points

    Hello, thank you for your reply.

    We have one additional inquiry from them.

    Please refer to the item below, and feedback us with your comment.

    When referring Figure 37 on page 14, DAC Resistor String is described.

    Please let us clarify how would this resistor string be in case power supply voltage was dropped below 2.7V. (would this switch be open or close?)

    We thank you once again for your information.

    Best regards,

  • 0 in reply to Atsushi Okui
    TI__Genius 16890 points

    Hi,

    The switches are set according to the value in the register.  If the supply voltage goes below 2.7V there is no guarantee that the switches will stay in that state.  As the voltage goes down at some point the circuitry will stop working.  When the part powers back up, a power on reset will occur and the register will be set to zero which will set the switches.

    Mike