Voltage Regulator Module (VRM) and Enterprise Voltage Regulator-Down (EVRD) 10.1 Design Guidelines

Voltage Regulator Module (VRM) and Enterprise Voltage 35
Regulator-Down (EVRD) 10.1 Design Guidelines
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 Thermal Design Current
(Icc (TDC)) over an ambient temperature range of 0ºC to +45ºC with a minimum airflow of
400 LFM. Operating conditions shall be considered to include 10 cycles between min and max
temperature as a rate of 10ºC/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 90ºC. At no time during the
operation is the board permitted to exceed 90ºC within a distance of 2.54 mm [0.100”] from the top
of connector (0.4 in. from board edge). In order not to exceed the 90ºC, it is recommended that the
board be constructed from 2-ounce copper cladding. Temperature and airflow measurements
should be made in close proximity to the VRM.
8.3 Non-Operating Temperature - PROPOSED
The VRM shall not be damaged when exposed to temperatures between –40ºC and +70ºC. These
shall be considered to include 50 cycles of minimum to maximum temperatures at 20ºC/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