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PCIEEXT-16HOT ADVANCED FEATURES
UNDER-VOLTAGE MARGINING
WARNING: UNDERVOLTAGING POWER MAY DAMAGE SOME UUTs OR
CAUSE SYSTEM CRASHES. USE AT YOUR OWN RISK.
The PCIeEXT-16-HOT allows application of reduced versions of +3.3V, +3.3AUX and +12V for the
purpose of margin testing the UUT.
If the MARGINING switch (top switch in Figure 1) is in the 0%
(top) position, no margining will be used, and the voltage fed to the UUT (when the Slot Power switch
is ON) will be the full voltage present at the power connections on the motherboard.
If the MARGINING switch is in the 5% (middle) position, the voltage supplied on the +3.3V and
+3.3AUX pins to the UUT will be approximately 3.15V.
This 3.15V voltage will be output to the UUT
even if the motherboard voltage is out of specification, as long as the motherboard voltage is over
3.2V.
Similarly, with the MARGINING Switch in the 5% position, the voltage supplied on the 12V pins
to the UUT will be approximately 11.4V, regardless of the motherboard voltage on the 12V pins, so
long as this voltage is 11.5V or higher.
If the MARGINING switch is in the 10% (bottom) position, the voltage supplied on the +3.3V and
+3.3AUX pins to the UUT will be approximately 3.0V. This 3.0V voltage will be output to the UUT even
if the motherboard voltage is out of spec, as long as the motherboard voltages are over 3.05V.
Similarly, with the MARGINING Switch in the 10% position, the voltage supplied on the 12V pins to the
UUT will be approximately 10.8V.
SLOW POWER SUPPLY RAMP-UP
The PCIeEXT-16-HOT turns all three power supplies on when the Slot Power switch is turned on, and
these voltages rise to full value in approximately 50-100 microseconds. On UUTs with large amounts of
bulk capacitance,
the resulting inrush current may exceed the host computer’s power supply
capability, causing the system to reset or hang. For such systems, installing the jumper at the M1 pair
will cause the power-un ramp to approximately 600 microseconds.
r1v05
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