Voltage Regulator Module (VRM) and Enterprise Voltage Regulator-Down (EVRD) 10.0 Design Guidelines

VRM and EVRD 10.0 Design Guidelines
R
32
8 VRM – Environmental Conditions
The VRM design, including materials, should be consistent with the manufacture of units that
meet the environmental requirements specified below.
8.1 Operating Temperature PROPOSED
The VRM shall meet all electrical requirements when operated at the Thermal Design Current
(Icc(TDC)) over an ambient temperature of 0 ºC to +60 ºC with a minimum airflow of 400 LFM
or 0 ºC to +45 ºC with a minimum airflow of 200 LFM. Operating conditions shall be considered
to include 10 cycles between minimum and maximum temperature as a rate of 10 ºC/hour and a
dwell time of 30 minutes at extremes. Temperature and airflow measurements should be made in
close proximity to the VRM.
8.2 VRM Board Temperature REQUIRED
To maintain the connector within its operating temperature range, the VRM board temperature, at
the connector interface, shall not exceed a temperature equal to 90 ºC. At no time during the
operation is the VRM board permitted to exceed 90 ºC within a distance of 2.54 mm [0.100
inches] from the top of the connector (equivalent to 10.16 mm [0.400 inches] from the VRM
board edge). In order not to exceed the 90 ºC, it is recommended that the board be constructed
from 2-ounce copper cladding.
8.3 Non-Operating Temperature PROPOSED
The VRM shall not be damaged when exposed to temperatures between –40 ºC and +70 ºC.
These shall be considered to include 50 cycles of minimum to maximum temperatures at 20
ºC/hour with a dwell time of 20 minutes at the extremes.
8.4 Humidity PROPOSED
85% relative – operating
95% relative – non-operating
8.5 Altitude PROPOSED
3.05 km [10k feet] – operating
15.24 km [50k feet] – non-operating