Intel® Server System R2000WF Product Family Technical Product Specification
47
Table 26. DC input rating
Parameter
Minimum
Rated
Maximum
DC Voltage
-40.5 VDC
-48 VDC/-60 VDC
-75 VDC
Input Current
24bA
12.5 A
3.4.2
DC Input Fuse
The power supply should have the -48 VDC input fused. The fusing shall be acceptable for all safety agency
requirements. DC inrush current shall not cause the fuse to blow under any conditions. No protection circuits
in the power supply shall cause the DC fuse to blow unless a component in the power supply has failed. This
includes DC output load short conditions.
3.4.3
DC Inrush Current
Maximum inrush current from power-on shall be limited to a level below the surge rating of the input line
cable; input diodes, fuse, and EMI filter components. To allow multiple power cycling events and DC line
transient conditions max I²t value shall not exceed 20% of the fuse max rating. Repetitive ON/OFF cycling of
the DC input line voltage should not damage the power supply or cause the input fuse to blow.
3.4.4
DC Input under Voltage
The power supply shall contain protection circuitry (under-voltage lock-out) such that the application of an
input voltage below the specified minimum specified, shall not cause damage (overstress) to the power
supply unit (due to over-heating or otherwise).
3.4.5
DC Holdup Time and Dropout
Table 27. DC holdup time
Loading
Holdup Time
750 W (100%)
0.2 msec
During a DC dropout of 0.2 msec or less the power supply must meet dynamic voltage regulation
requirements for every rated load condition. A DC line dropout of 0.2 msec or less shall not cause tripping of
control signals or protection circuits. Repeated every ten seconds starting at the minimum input voltage, DC
line dropout shall not damage the power supply under any specified load conditions. The PWOK signal shall
not go to a low state under these conditions. DC dropout transients in excess of 0.2 msec may cause
shutdown of the power supply or out of regulation conditions, but shall not damage the power supply. The
power supply should recover and meet all turn on requirements for DC dropouts that last longer than
0.2 msec. The power supply must meet the DC dropout requirement over rated DC voltages and output
loading conditions.
3.4.6
DC Line Surge Voltages (Line Transients)
The power supply should demonstrate tolerance for transients in the input DC power line caused by
switching or lightning. The power supply shall be primarily tested and must be compliant with the
requirements of EN61000-4-5: “Electrical Fast transients / Burst Requirements and Surge Immunity
Requirements” for surge withstand capability. The test voltage surge levels are to be 500Vpk for each Line to
Primary Earth Ground test (none required between the L1 and L2). The exact description can be found in
Intel Environmental Standards Handbook 2001
.
Table 28. Line voltage transient limits
Duration
Slope/Rate
Output
Performance Criteria
200 µsec max
-48 V → -30 V w/ +2 V/µs
Rated DC voltages
No loss of function or performance
-30 V → -48 V w/ -2 V/µs
Rated DC voltages
No loss of function or performance
