Datasheet

cui.com
date 11/07/2014 │ page 3 of 30CUI Inc │ SERIES: NQB-N │ DESCRIPTION: FULLY REGULATED ADVANCED BUS CONVERTERS
General Information
Reliability
The failure rate (λ) and mean time between failures
(MTBF= 1/ λ) is calculated at max output power and
an operating ambient temperature (T
A
) of +40°C. CUI
Power Modules uses Telcordia SR-332 Issue 2 Method 1 to
calculate the mean steady-state failure rate and standard
deviation (σ).
Telcordia SR-332 Issue 2 also provides techniques to
estimate the upper condence levels of failure rates based
on the mean and standard deviation.
Mean steady-state failure rate, λ Std. deviation, σ
h/seruliaFn9.06h/seruliaFn124
MTBF (mean value) for the NQB series = 2.9 Mh.
MTBF at 90% condence level = 2.4 Mh
Compatibility with RoHS requirements
The products are compatible with the relevant clauses
and requirements of the RoHS directive 2011/65/EU and
have a maximum concentration value of 0.1% by weight
in homogeneous materials for lead, mercury, hexavalent
chromium, PBB and PBDE and of 0.01% by weight in
homogeneous materials for cadmium.
Exemptions in the RoHS directive utilized in CUI
Power Modules products are found in the Statement of
Compliance document.
Safety Specification
Reliability
CUI Power Modules DC/DC converters and DC/DC
regulators are designed in accordance with the safety
standards IEC 60950 1, EN 60950 1 and UL 60950 1
Safety of Information Technology Equipment.
IEC/EN/UL 60950 1 contains requirements to prevent
injury or damage due to the following hazards:
• Electrical shock
• Energy hazards
• Fire
• Mechanical and heat hazards
• Radiation hazards
• Chemical hazards
On-board DC/DC converters and DC/DC regulators are
dened as component power supplies. As components
they cannot fully comply with the provisions of any
safety requirements without “conditions of acceptability”.
Clearance between conductors and between conductive
parts of the component power supply and conductors on
the board in the nal product must meet the applicable
safety requirements. Certain conditions of acceptability
apply for component power supplies with limited stand-off
(see Mechanical Information for further information). It is
the responsibility of the installer to ensure that the nal
product housing these components complies with
the requirements of all applicable safety standards and
regulations for the nal product.
Component power supplies for general use should comply
with the requirements in IEC/EN/UL 60950 1 Safety
of Information Technology Equipment. Product related
standards, e.g. IEEE 802.3af Power over Ethernet, and
ETS 300132 2 Power interface at the input to telecom
equipment, operated by direct current (dc) are based on
IEC/EN/UL 60950 1 with regards to safety.
CUI Power Modules DC/DC converters and DC/DC
regulators are UL 60950 1 recognized and certied in
accordance with EN 60950 1. The ammability rating for
all construction parts of the products meet requirements
for V 0 class material according to IEC 60695 11 10, Fire
hazard testing, test ames – 50 W horizontal and vertical
ame test methods.
Isolated DC/DC converters
Galvanic isolation between input and output is veried
in an electric strength test and the isolation voltage
(V
iso
) meets the voltage strength requirement for basic
insulation according to IEC/EN/UL 60950-1.
It is recommended to use a slow blow fuse at the input
of each DC/DC converter. If an input lter is used in the
circuit the fuse should be placed in front of the input lter.
In the rare event of a component problem that imposes a
short circuit on the input source, this fuse will provide the
following functions:
• Isolate the fault from the input power source so as
not to affect the operation of other parts of
the system
• Protect the distribution wiring from excessive
current and power loss thus preventing hazardous
overheating
The DC/DC converter output is considered as safety extra
low voltage (SELV) if one of the following conditions is
met:
• The input source has double or reinforced
insulation from the AC mains according to IEC/EN/
UL 60950-1
• The input source has basic or supplementary
insulation from the AC mains and the input
of the DC/DC converter is maximum 60
Vdc and connected to protective earth according to
IEC/EN/UL 60950-1
• The input source has basic or supplementary
insulation from the AC mains and the DC/DC
converter output is connected to protective earth
according to IEC/EN/UL 60950-1
Non - isolated DC/DC regulators
The DC/DC regulator output is SELV if the input source
meets the requirements for SELV circuits according to IEC/
EN/UL 60950-1.
For more information, please visit the product page.