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MDC_ICH_500W_A04 Page 9 of 17

ICH 500-Watt Series

Wide Input Isolated Half Brick DC-DC

Thermal Consideration

The ICH converter can operate in a variety of thermal environments.

However, in order to ensure reliable operation of the converter,

sufficient cooling should be provided.

The ICH converter is

encapsulated in plastic case with metal baseplate on the top. In order

to improve thermal performance, power components inside the unit

are thermally coupled to the baseplate. In addition, thermal design of

the converter is enhanced by use of input and out pins as heat transfer

elements.

Heat is removed from the converter by conduction,

convection and radiation.

There are several factors such as ambient temperature, airflow,

converter power dissipation, converter orientation how converter is

mounted as well as the need for increased reliability that need to be

taken into account in order to achieve required performance. It is

highly recommended to measure temperature in the middle of the

baseplate in particular application to ensure that proper cooling of the

convert is provided.

A reduction in the operating temperature of the converter will result in

an increased reliability.

Thermal Derating

There are two most common applications: 1) the ICH converter is

thermally attached to a cold plate inside chassis without any forced

internal air circulation; 2) the ICH converter is mounted in an open

chassis on system board with forced airflow with or without an

additional heatsink attached to the baseplate of the ICH converter.

The best thermal results are achieved in application 1) since the

converter is cooled entirely by conduction of heat from the top surface

of the converter to a cold plate and temperature of the components is

determined by the temperature of the cold plate. There is also some

additional heat removal through the converters pins to the metal layers

in the system board. It is highly recommended to solder pins to the

system board rather than using receptacles. Typical derating output

power and current are shown in Figs. 10–15 for various baseplate

temperatures up to 105ºC. Note that operating converter at these

limits for prolonged time will affect reliability.

Soldering Guidelines

The RoHS-compliant through hole ICH converters use Sn/Ag/Cu Pb-

free solder and RoHS compliant components. They are designed to be

processed through wave soldering machines.

The pins are 100%

matte tin over nickel plated and compatible with both Pb and Pb-free

wave soldering processes. It is recommended to follow specifications

below when installing and soldering ICH converters. Exceeding these

specifications may cause damage to the ICH converter.

Wave Solder Guideline for Sn/Ag/Cu based solders

Maximum Preheat Temperature

115ºC

Maximum Pot Temperature

270ºC

Maximum Solder Dwell Time

7 seconds

Wave Solder Guideline for SN/Pb based solders

Maximum Preheat Temperature

105ºC

Maximum Pot Temperature

250ºC

Maximum Solder Dwell Time

6 seconds

ICH converters are not recommended for water wash process. Contact

the factory for additional information if water wash is necessary.

Fig. 3: Test setup for measuring output voltage ripple, startup and step

load transient waveforms.