mystery PLL chip

[Soulkeeper]

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

 

[William Gaatjes]

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

Situated between the PCIe x16 slots we find an ICS clock generator, none other than the ICS 9LPRS477DKL. Specifically designed for the AMD platform, it controls all host clocks, CPU and Southbridge included, and is accessed via an SMBUS interface. The final board component, from JMicron, the JMB362, provides support for the dual eSATA 3.0 Gb/s ports found on the rear I/O. Having been on the market for several years, the JMB362 seems to fit in perfectly with what we expect from the ASUS M5A97 EVO.

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.

 

[William Gaatjes]

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.

 

[Soulkeeper]

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

In a nutshell, the standard options include the CPU multiplier that allows to dial in the CPU clock in multiples of the base clock (100 MHz default). Nothing really new on that front. All other clocks are derived from the main PLL running at 3600 MHz by using dividers that are stepped at 0.25 intervals.

 

[William Gaatjes]

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.

 

[Soulkeeper]

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

 

[William Gaatjes]

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

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.