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TPS549D22: Pin Strap Register Settings on Powerup and NVM

Part Number: TPS549D22

I have a question about the default values of the following registers on reset...


The lower 10-bits are set by the pin-strap on boot/initializaiton.

I understand that the initial boot voltage starts up with the last saved NVM configuration of VOUT_COMMAND if the pin strap is either Open, 187 kΩ, 1.78 kΩ, or 0 Ω (short); otherwise the pin strap resistor RVSEL takes precedence.

But what about in the default state where NVM has yet to have any value stored to it?
What are the 10-bits in these registers then?


  • Hi Darren,

    Your understanding regarding the pin strap behavior is correct.

    The TPS549D22 has the following defaults:

    VOUT_COMMAND (21h)」= 499d
    VOUT_MARGIN_HIGH (25h)」= 461d
    VOUT_MARGIN_LO (26h)」= 461d

    This means that the 10 bits relevant to operation are as follows:

    「VOUT_COMMAND (21h)」= 01 1111 0011b
    「VOUT_MARGIN_HIGH (25h)」= 01 1100 1101b
    「VOUT_MARGIN_LO (26h)」= 01 1100 1101b


    Alec Biesterfeld