Intel® SRMK2 Internet Server Technical Product Specification
19
Table 5: Baseboard Power Connector (P3)
Pin
Signal Name
20 AWG Wire
Pin
Signal Name
20 AWG Wire
1
HECALERT#*
N/A
6
SMB_Data*
N/A
2
Ground
Black
7
SMB_CLK*
N/A
3
Ground Sense
Black
8
+3.3V Sense
Brown
4
PWR_ON#
Green
9
PWRGOOD
Grey
5
-12V
Blue
10
+5V Sense
Red
*
These pins are not stuffed or used on the SRMK2 power supply
Table 6: SCSI Backplane Power Connector (P4)
Pin
Signal Name 20 AWG Wire
1
+12V
Yellow
2
+12V
Yellow
3
Ground
Black
4
Ground
Black
5
+3.3V
Orange
6
+5V
Red
2.2.2 DC Power Supply
The SRMK2D model ships with a –48V DC power supply. The output of the DC power supply is
electrically identical to that of the AC power supply (see Table 3 for reference), it shares the
same physical dimensions as the AC power supply, the same mounting, and the same power
cabling to the motherboard. It does vary, however, in it’s electrical specification for line input and
has a different interface on the rear of the chassis than the AC module. The interface on the
back of the DC power supply has four phillips screws that are protected by a cover for shipping.
Removing the cover reveals the four screws. A label should show the screw markings to be: A+
A- B+ B- . The A+ and A- connectors can be attached to a primary power source for the
server, while the B+ and B- leads can be connected to a secondary power source for redundant
power sourcing in case of primary source failure. Table 7 shows the input parameters for the –
48V DC power supply.
Table 7: -48V DC Power Supply Input Parameters
Parameter
Min
Nom
Max
Unit
Vin (-48VDC)
-36.0
-48.0
-72.0
VDC
2.2.3 BTU information
BTU’s (British Thermal Units) are a standard for measuring the thermal output of a device. For
reference, one BTU equals the heat that will raise the temperature of one pound of water by one
degree Fahrenheit. In physical terms, 1 BTU = 1054 joules. Listed below is the maximum BTU
output of the SRMK2 system and a loaded system BTU output. System configuration of the
loaded system is described in Table 9.
The BTU maximum rating was derived by taking the maximum wattage output of the power
supply (202.9W), dividing it by the lowest efficiency of the power supply (70% or 0.70) and
multiplying by the BTU conversion number of 3.41. Remember that these numbers are rated at
