a) Measurements made differentially to eliminate common-mode noise
b) Ground lead length of oscilloscope probe shall be ≤ 0.25 inch.
c) Measurements made where the cable connectors attach to the load.
d) Outputs bypassed at the point of measurement with a parallel combination of
10uF tantalum capacitor in parallel with a 0.1uF ceramic capacitors.
e) Oscilloscope bandwidth of 0 Hz to 20MHz.
f) Measurements measured at locations where remote sense wires are connected.
g) Regulation tolerance shall include temperature change, warm up drift and dynamic load
3.3 Timing Requirements
These are the timing requirements for the power assembly operation. The output voltages must rise
from 10% to within regulation limits (T
vout_rise) within 5 to 70mS. The +5V, +3.3V and +12V output
voltages should start to rise at about 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 50 mS (T
vout_on) of each other during turn on of the power supply. Each output voltage
shall fall out of regulation within 400 mS (T
vout_off) of each other during turn off. Figure 1 and figure 2
show the turn On and turn Off timing requirement. In Figure 2, the timing is shown with both AC and
PSON# controlling the On/Off of the power supply.
stinU XAM NIM noitpircseD metI
Tvout_rise Output voltage rise time from each main output.(+5Vsb <
70mS)
5 70 mS
Tvout_on All main output must be within regulation of each other
within this time.
50 mS
Tvout_off All main output must leave regulation within this time 400 mS
Table 4 – Output Voltage Timing
