Instruction Manual

Design Guide & Applications Manual
F
or Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies
Maxi, Mini, Micro Design Guide Rev 4.9 vicorpower.com
Page 25 of 88
Apps. Eng. 800 927.9474 800 735.6200
The following pages contain temperature derating curves.
For additional thermal data, see the following link:
http://asp.vicorpower.com/calculators/calculators.asp?calc=5
Additional Thermal Data
6. Thermal Performance Information
The relevant nomenclature for the tabulated thermal information supplied in this section for the
Maxi, Mini, and Micro modules is defined as follows:
Tb = baseplate temperature
Ta = ambient temperature
Pout = module output power
Pi
n
= module input power
η = module efficiency = Pout / Pin
Pdiss = module power dissipation = Pin – Pout = (1/η – 1) • Pout
Supplied thermal resistance values:
θbs = baseplate-to-heatsink thermal resistance
θba = baseplate-to-ambient thermal resistance
Basis of output power versus ambient temperature derating curves:
(Ta)max = (Tb)max – θba • Pdiss = (Tb)max – θba • (1/η – 1) • Pout
Simplified thermal management is one of the benefits of
using Vicor converters. High operating efficiency minimizes
heat loss, and the low-profile package features an easily
a
ccessible, electrically isolated thermal interface surface.
Proper thermal management pays dividends in terms of
improved converter and system MTBFs, smaller size, and
lower product life-cycle costs. The following pages provide
guidelines for achieving effective thermal management of
Vicor converters.
Consideration should be given to the module baseplate
temperature during operation. The maximum baseplate
temperature specification for Maxi, Mini, and Micro is
1
00°C.
Enhanced module cooling can be achieved with free or
forced convection by using the appropriate heat sink. The
available Vicor heat sinks and thermal interface options
are available on the Vicor website.