Intel
®
Server Board S5500BC TPS
Power and Environmental Specifications
Revision 1.0
Intel order number: E42249-003
73
required. The power supply manufacturer should provide proof of the unit’s closed-loop stability
with local sensing through the submission of bode plots. Closed-loop stability must be
maintained at the maximum and minimum loads as applicable.
8.2.10
Common Mode Noise
The common mode noise on any output should not exceed 350 mV peak-peak over the
frequency band of 10 Hz to 30 MHz.
The measurement should be made across a 100
Ω
resistor between each of the DC
outputs, including ground, at the DC power connector and chassis ground (power
subsystem enclosure).
The test set-up should use an FET probe such as a Tektronix P6046* model or
equivalent.
8.2.11
Ripple / Noise
The maximum allowed ripple/noise output of the power supply is defined in the following table.
This is measured over a bandwidth of 0 Hz to 20 MHz at the power supply output connectors. A
10
F tantalum capacitor in parallel with a 0.1
F ceramic capacitor are placed at the point of
measurement.
Table 38. Ripple and Noise
+3.3 V
+5 V
+12 V
-12 V
+5 VSB
50mVp-p 50mVp-p 120mVp-p 120mVp-p 50mVp-p
8.2.12 Soft
Starting
The power supply should contain a control circuit which provides a monotonic soft start for the
outputs without overstressing the AC line or any power supply components at any specified AC
line or load conditions. There is no requirement for rise time on the 5 V standby but the turn
on/off should be monotonic.
8.2.13
Timing Requirements
The output voltages must rise from 10% to within regulation limits (T
vout_rise
) within 5 to 70 ms,
except for 5 VSB; it is allowed to rise from 1.0 to 25 ms. All outputs must rise monotonically.
Each output voltage should reach regulation within 50 ms (T
vout_on
) of each other during power
on. Each output voltage should fall out of regulation within 400 msec (T
vout_off
) of each other
during turn off. The following tables show the timing requirements to turn the power supply on
and off via the AC input with PSOn held low, and the PSOn signal with the AC input applied.
