Intel LF80550KF0804M Data Sheet

72

Dual-Core Intel® Xeon® Processor 7100 Series Datasheet

V

CC_CACHE_SENSE

V

SS_CACHE_SENSE

O

V

CC_CACHE_SENSE

 and V

SS_CACHE_SENSE

 provide isolated, low impedance 

connections to the processor cache voltage (V

CACHE

) and ground (V

SS

). They 

can be used to sense or measure voltage or ground near the silicon with little 

noise.

V

CCIOPLL

I

V

CCIOPLL

 provides isolated power for digital portion of the internal PLL’s. Follow 

the guidelines for V

CCA

, and refer to the appropriate platform design guide for 

complete implementation details.

V

CCPLL

I

The on-die PLL filter solution will not be implemented on this platform. The 

V

CCPLL

 input should be left unconnected.

V

CCSENSE

V

SSSENSE

O

V

CCSENSE

 and V

SSSENSE

 provide isolated, low impedance connections to the 

processor core voltage (V

CC

) and ground (V

SS

). These signals must be 

connected to the voltage regulator feedback signals, which ensure the output 

voltage (i.e. processor voltage) remains within specification. Please see the 

applicable platform design guide for implementation details.

VID[5:0]

O

VID[5:0] (Voltage ID) pins are used to support automatic selection of V

CC

. 

These are open drain signals that are driven by the processor and must be 

pulled to no more than 3.3 V (+5% tolerance) with a resistor. Conversely, the 

V

CC

 VR output must be disabled prior to the voltage supply for these pins 

becoming invalid. The VID pins are needed to support processor voltage 

specification variations. See 

 for definitions of these pins. The V

CC

 VR 

must supply the voltage that is requested by these pins, or disable itself.

VIDPWRGD

I

The processor requires this input to determine that the supply voltage for 

BSEL[1:0], VID[5:0], and CVID[3:0] is stable and within specification.

V

SS

I

V

SS

 is the ground plane for the Dual-Core Intel Xeon processor 7100 series.

V

SSA

I

V

SSA

 provides an isolated, internal ground for internal PLL’s. Do not connect 

directly to ground. This pin is to be connected to V

CCA

 and V

CCIOPLL

 through a 

discrete filter circuit.

V

TT

I

V

TT

 is the front side bus termination voltage.

VTTEN

O

VTTEN can be used as an output enable for the V

TT

 regulator. VTTEN is used as 

an electrical key to prevent processors with mechanically-equivalent pinouts 

from accidentally booting in a Dual-Core Intel Xeon processor 7100 series 

platform. Since VTTEN is an open circuit on the processor package, VTTEN 

must be pulled up on the motherboard. Refer to the appropriate platform 

design guide for implementation details.