Specification Sheet
Electrical Specifications
132 Intel
®
 Xeon
®
 Processor E5-1600/E5-2600/E5-4600 v2 Product Families 
Datasheet Volume One of Two
7.1.5 Platform Environmental Control Interface (PECI)
PECI is an Intel proprietary interface that provides a communication channel between 
Intel processors and chipset components to external system management logic and 
thermal monitoring devices. The processor contains a Digital Thermal Sensor (DTS) 
that reports a relative die temperature as an offset from Thermal Control Circuit (TCC) 
activation temperature. Temperature sensors located throughout the die are 
implemented as analog-to-digital converters calibrated at the factory. PECI provides an 
interface for external devices to read processor temperature, perform processor 
manageability functions, and manage processor interface tuning and diagnostics. 
The PECI interface operates at a nominal voltage set by V
TTD
. The set of DC electrical 
specifications shown in Table 7-16 is used with devices normally operating from a V
TTD
interface supply.
7.1.5.1 Input Device Hysteresis
The PECI client and host input buffers must use a Schmitt-triggered input design for 
improved noise immunity. Please refer to Figure 7-1 and Tabl e 7 -1 6.
7.1.6 System Reference Clocks (BCLK{0/1}_DP, 
BCLK{0/1}_DN)
The processor core, processor uncore, Intel® QuickPath Interconnect link, PCI 
Express* and DDR3 memory interface frequencies) are generated from BCLK{0/1}_DP 
and BCLK{0/1}_DN signals. There is no direct link between core frequency and Intel 
QuickPath Interconnect link frequency (e.g., no core frequency to Intel QuickPath 
Interconnect multiplier). The processor maximum core frequency, Intel QuickPath 
Interconnect link frequency and DDR memory frequency are set during manufacturing. 
It is possible to override the processor core frequency setting using software. 
This permits operation at lower core frequencies than the factory set maximum  
core frequency.
The processor core frequency is configured during reset by using values stored within 
the device during manufacturing. The stored value sets the lowest core multiplier at 
which the particular processor can operate. If higher speeds are desired, the ratio can 
be configured via the IA32_PERF_CTL MSR (MSR 199h); Bits [15:0]. 
Figure 7-1. Input Device Hysteresis
Minimum V
P
Maximum V
P
Minimum V
N
Maximum V
N
PECI High Range
PECI Low Range
Valid Input
Signal Range
Mi ni mum
Hysteresis
V
TTD
PECI Ground










