Intel Celeron 360 HH80552RE099512 User Manual

13

This chapter describes the electrical characteristics of the processor interfaces and 

signals. DC electrical characteristics are provided.

The Celeron D processor has 226 VCC (power), 24 VTT and 273 VSS (ground) inputs 

for on-chip power distribution. All power lands must be connected to V

CC

, while all VSS 

lands must be connected to a system ground plane. The processor VCC lands must be 

supplied with the voltage determined by the Voltage IDentification (VID) lands. 

Twenty-four (24) signals are denoted as V

TT

 that provide termination for the front side 

bus and power to the I/O buffers. A separate supply must be implemented for these 

lands that meets the V

TT

Due to its large number of transistors and high internal clock speeds, the processor is 

capable of generating large current swings. This may cause voltages on power planes 

to sag below their minimum specified values if bulk decoupling is not adequate. Larger 

bulk storage (C

BULK

), such as electrolytic or aluminum-polymer capacitors, supply 

current during longer lasting changes in current demand by the component, such as 

coming out of an idle condition. Similarly, they act as a storage well for current when 

entering an idle condition from a running condition. The motherboard must be designed 

to ensure that the voltage provided to the processor remains within the specifications 

listed in 

. Failure to do so can result in timing violations or reduced lifetime of 

the component. 

V

CC

 regulator solutions need to provide sufficient decoupling capacitance to satisfy the 

processor voltage specifications. This includes bulk capacitance with low effective series 

resistance (ESR) to keep the voltage rail within specifications during large swings in 

load current. In addition, ceramic decoupling capacitors are required to filter high 

frequency content generated by the front side bus and processor activity. Consult the 

LGA775 Socket for further information.