Intel SC5299WS User Manual

2.1.5.7 

Capacitive Loading 

The power supply is stable and meets all requirements with the following capacitive loading 
ranges. 

Output 

MIN 

MAX 

Units 

+3.3V 250 6,800 

  F 

+5V 400 4,700 

  F 

+12V(1, 2) 

500 each 

11,000 

  F 

-12V 1  350 

  F 

+5VSB 20  350 

  F 

2.1.5.8 

Closed Loop Stability 

The power supply is unconditionally stable under all line/load/transient load conditions, including 
capacitive load ranges. A minimum of: 45 degrees phase margin and -8dB-gain margin is 
required. Closed-loop stability is ensured at the maximum and minimum loads as applicable. 

2.1.5.9 

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. 

+3.3V 

+5V 

+12V1/2 

-12V 

+5VSB 

50mVp-p 50mVp-p 120mVp-p  120mVp-p  50mVp-p 

 

2.1.5.10 

Timing Requirements 

The timing requirements for power supply operation are as follows. The output voltages must 
rise from 10% to within regulation limits (T

vout_rise

) within 2 to 20ms, except for 5VSB which is 

allowed to rise from 1.0 to 70ms. The +3.3V, +5V and +12V output voltages should start to rise 
approximately at the same time. All outputs must rise monotonically. The +5V output needs to 
be greater than the +3.3V output during any point of the voltage rise. The +5V output must 
never be greater than the +3.3V output by more than 2.25V. Each output voltage shall reach 
regulation within 50ms (T

vout_on

) of each other during turn on of the power supply. Each output 

voltage shall fall out of regulation within 400msec (T

vout_off

) of each other during turn off. The 

following figure shows the timing requirements for the power supply being turned on and off via 
the AC input, with PSON held low and the PSON signal, with the AC input applied.