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Powering the C6657/55/54

Michael Butts
Prodigy 180 points
Other Parts Discussed in Thread: LM10011, LM10010

http://www.ti.com/product/tms320c6657 under reference designs

  1. The title on the reference designs say TMS320C667x – is this a typo or a power solution that fits both the c667x and c665x familiy of DSPs?
  2. The two designs are different in that the PMP7303 is a single phase design and the PMP7256 is a multi-phase design -  Is the single phase for the 6655/54 and the two phase is for 6657?
  • 0
    TI__Mastermind 42545 points

    1) These two reference designs are generic to Keystone I processors but were initially created for the C667x parts.

    2) The single phase design is used when only one C665x device is on the board. It will provide a single AVS supply output that will modify the supply level based on the VCNTL interface using the LM10011.  The dual phase design can be used if you have two C665x in your design.  VOUT1 would be the AVS voltage for the first C665x and VOUT2 would be the AVS voltage for the second C665x.  Alternatively the second phase of the power supply could be set to 1V to provide the CVDD1 rail for a single C665x.

    Note that these reference designs currently specify the LM10010 as the VCNTL interface component.  We are recommending the LM10011 component in place of the LM10010.  It provides a more accurate output current and provides the ability to set the start-up voltage using the Rset resistor.  This is necessary because the initial voltage for the C665x AVS voltage should be 1.1V until the value is modified by the VCNTL interface.  The LM10010 has a start-up voltage of 1V. 

  • 0 in reply to Bill Taboada
    TI__Intellectual 1935 points

    Hey Bill,

    Thanks for the useful insight on this.  If I am reading the last paragraph correctly, you are saying that they initial voltage the C6655 needs to see is 1.1V until the current DAC communicates back to the controller to output 1V.  If you were to use the LM10010 it would tell the controller to output 1V during start up which is not compliant with the C6655.

    Is that correct?

    Thanks,
    Casey

  • 0 in reply to Casey Davidson
    TI__Mastermind 42545 points

    Hi Casey,

    Your statement is correct.  Note that the LM10010 and the LM10011 are pin compatible with the exception of pins 5 and 6.  These pins were NC on the LM10010.  On the LM10011 pin 5 should be connected to ground to select the 4pin, 6bit VID interface and the Rset resistor should be connected between pin 6 and ground to set an initial voltage of 1.1V.

    Regards, Bill