Q36SR12017_12272012
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CSA C22.2 NO. 60950-1 2nd and IEC 60950-1 2nd : 2005
and EN 60950-1 2nd: 2006+A11+A1: 2010,if the system in
which the power module is to be used must meet safety
agency requirements.
Basic insulation based on 75 Vdc input is provided between
the input and output of the module for the purpose of
applying insulation requirements when the input to this
DC-to-DC converter is identified as TNV-2 or SELV. An
additional evaluation is needed if the source is other than
TNV-2 or SELV.
When the input source is SELV circuit, the power module
meets SELV (safety extra-low voltage) requirements. If the
input source is a hazardous voltage which is greater than 60
Vdc and less than or equal to 75 Vdc, for the module’s
output to meet SELV requirements, all of the following must
be met:
The input source must be insulated from the ac mains
by reinforced or double insulation.
The input terminals of the module are not operator
accessible.
A SELV reliability test is conducted on the system
where the module is used in combination with the
module, to ensure that under a single fault, hazardous
voltage does not appear at the module’s output.
When installed into a Class II equipment (without
grounding), spacing consideration should be given to the
end-use installation, as the spacing between the module
and mounting surface have not been evaluated.
The power module has extra-low voltage (ELV) outputs
when all inputs are ELV.
This power module is not internally fused. To achieve
optimum safety and system protection, an input line fuse is
highly recommended. The safety agencies require a
Fast-acting fuse with 50A maximum rating to be installed in
the ungrounded lead. A lower rated fuse can be used
based on the maximum inrush transient energy and
maximum input current.
Soldering and Cleaning Considerations
Post solder cleaning is usually the final board assembly
process before the board or system undergoes electrical
testing. Inadequate cleaning and/or drying may lower the
reliability of a power module and severely affect the finished
circuit board assembly test. Adequate cleaning and/or
drying is especially important for un-encapsulated and/or
open frame type power modules. For assistance on
appropriate soldering and cleaning procedures, please
contact Delta’s technical support team.
DESIGN CONSIDERATIONS
Input Source Impedance
The impedance of the input source connecting to the DC/DC
power modules will interact with the modules and affect the
stability. A low ac-impedance input source is recommended.
If the source inductance is more than a few µH, we advise
adding a 100 µF electrolytic capacitor (ESR < 0.7 Ω at 100
kHz) mounted close to the input of the module to improve
the stability.
Layout and EMC Considerations
Delta’s DC/DC power modules are designed to operate in a
wide variety of systems and applications. For design
assistance with EMC compliance and related PWB layout
issues, please contact Delta’s technical support team. An
external input filter module is available for easier EMC
compliance design. Below is the reference design for an
input filter tested with Q36SR12017 to meet class A in
CISSPR 22.
Schematic
Test result:
25C, 48Vin, full load, Green line is quasi peak mode and
blue line is average mode.
Safet y Consideration s
The power module must be installed in compliance with the
spacing and separation requirements of the end-user’s
safety agency standard, i.e., UL60950-1,
