mystery PLL chip

Discussion in 'Highly Technical' started by Soulkeeper, Jan 2, 2013.

  1. Soulkeeper

    Soulkeeper Diamond Member

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    I have an ICS 9LPRS477DKL on my motherboard.
    I can't seem to locate a datasheet for it.
    From what i've been reading it may be operating at 3.6GHz(apparently the pll that divisors are used to generate other clocks with) with 2.5v (bios default pll voltage).
    Am I looking at the right chip ?
    Does this thing really operate at 3.6GHz ?

    thanks
     
  2. William Gaatjes

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    Most likely it is an ic from IDT.

    But i have not found a datasheet yet.
    However, there are a lot of i.c. that have similar product labels.


    Here is a website :
    http://www.techpowerup.com/reviews/ASUS/M5A97_EVO/5.html

    [​IMG]


    Here is the IDT website :
    http://www.idt.com/products/clocks-timing/application-specific-clocks/computing-clocks

    These chips are made for the RS790 chipset from AMD/ATI.
    9LPRS471
    9LPRS478

    You seek the 9LPRS477.

    What kind of motherboard is it and cpu that have you ?
    It must be a recent model, looking at the production date of the chip : 1107.
    I am guessing 2011 week 7. But it can also be 2007 week 11.
     
    #2 William Gaatjes, Jan 3, 2013
    Last edited: Jan 3, 2013
  3. William Gaatjes

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    Your chip has 16 pins on 4 sides.
    That makes 64 pins and (exposed)pad.
    The 9LPRS477 has 64 pins.
    The 9LPRS471 has also 64 pins.
    Maybe you have a derivate.

    You need to contact IDT to get more information. There are probably patent rights involved in the manufacturing of the chip. Structures and logic that IDT does not own but has acquired through license. That may be why there is not much information about these chips.
     
  4. Soulkeeper

    Soulkeeper Diamond Member

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    Thanks for the replys, I got the same website and some deadends searching myself.

    This is a ga-a75m-ud2h motherboard with a llano cpu
    I'm just wondering if that is the PLL
    Also 2.5v default seems high to me, compared to other motherboards which typically set them under 2v. I'm curious I suppose.

    website

     
    #4 Soulkeeper, Jan 3, 2013
    Last edited: Jan 3, 2013
  5. William Gaatjes

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    You are referring to 2.5V ?
    With respect to the 9LPRS471.
    I see in the parametric table, that the output voltage can be set between 0.7V and 3.3V. The core voltage of the IC itself is 3.3V. The output frequency can be set between 14.32MHz and 355MHz with a crystal of 14.32MHz.
     
  6. Soulkeeper

    Soulkeeper Diamond Member

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    So maybe the 3.6GHz is not to do with this chip at all then :/

    I've heard "internal PLL" used in reference to fm2 boards
    maybe 3.6GHz is just an arbitrary number based off a 100MHz clock
     
  7. William Gaatjes

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    I doubt that would be the case. Running 3.6GHz clock on a pcb is possible but very tricky and expensive. No, it makes more sense that the base clock is set with this IC. Probably the RS970 chipset is clocked by this chip and the RS970 chipset has an PLL and buffers the PLL output clock and outputs it to the CPU. Probably the hypertransport clock or something like that.
    And inside the cpu there is a PLL (Phase Locked Loop) circuit that creates a 3.6GHz clock for the internal logic of the cpu from the externally applied clock.
     
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