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

VRM – Environmental Conditions
36 Voltage Regulator Module (VRM) and Enterprise Voltage
Regulator-Down (EVRD) 10.1 Design Guidelines
8.6 Electrostatic Discharge - PROPOSED
Testing shall be in accordance with IEC 61000-4-2.
Operating – 15 kV initialization level. The direct ESD event shall cause no out-of-regulation
conditions – including overshoot, undershoot and nuisance trips of over-voltage protection, over-
current protection or remote shutdown circuitry.
Non-operating –25 kV initialization level. The direct ESD event shall not cause damage to the
VRM circuitry.
8.7 Shock and Vibration - PROPOSED
The shock and vibration tests should be applied at the baseboard level. The VRM should not be
damaged and the interconnect integrity not compromised during:
• A shock of 30g with a 11ms half sine wave, non-operating, to be applied in each of the
orthogonal axes.
• Vibration of 0.01g² per Hz at 5 Hz, sloping to 0.02g² per Hz at 20 Hz and maintaining 0.02g²
per Hz from 20 Hz to 500 Hz, non-operating, applied in each of the orthogonal axes.
8.8 Electromagnetic Compatibility - PROPOSED
Design, including materials, should be consistent with the manufacture of units that comply with
the limits of FCC Class B and CISPR22 Class B for radiated emissions.
8.9 Reliability - PROPOSED
Design, including materials, should be consistent with the manufacture of units with a Mean Time
Between Failure (MTBF) of 500,000 hours of continuous operation at 55ºC, maximum-outputs
load, and worst-case line, while meeting specified requirements. MTBF should be calculated in
accordance with MIL-STD-217F or Bellcore.
8.10 Safety - PROPOSED
The voltage regulator is to be UL Recognized to standard UL1950 3rd Ed., including requirements
of IEC950 and EN 60950. Plastic parts and printed wiring board are to be UL Recognized with
94V-0-flame class.
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