Datasheet

cui.com
date 11/07/2014 │ page 24 of 36CUI Inc │ SERIES: NQB-D │ DESCRIPTION: FULLY REGULATED ADVANCED BUS CONVERTERS
The NQB products are designed to be fully regulated
within the plotted area. Operating outside this area is not
recommended.
Output Voltage Regulation
12.0
12.2
12.4
12.6
12.8
13.0
13.2
13.4
35 45 55 65 75
Vin [V]
Vout [V]
Vin range: 36-75Vdc
12.0
12.2
12.4
12.6
12.8
13.0
13.2
13.4
35 40 45 50 55 60
65
Vin [V]
Vout [V]
Vin range:40-60Vdc
Thermal Consideration
The product is designed to operate in different thermal
environments and sufcient cooling must be provided
to ensure reliable operation. For products mounted on
a PWB without a heat sink attached, cooling is achieved
mainly by conduction, from the pins to the host board,
and convection, which is dependant on the airow across
the product. Increased airow enhances the cooling of
the product. The Output Current Derating graph found in
the output section for each model provides the available
output current vs. ambient air temperature and air velocity
at V
I
=53 V.
The product is tested on a 254 x 254 mm, 35 µm (1 oz),
16-layer test board mounted vertically in a wind tunnel
with a cross-section of 608 x 203 mm.
General
For products with base plate used in a sealed box/cold
wall application, cooling is achieved mainly by conduction
through the cold wall. The Output Current Derating graphs
are found in the output section for each model. The
product is tested in a sealed box test set up with ambient
temperatures 85, 55 and 25°C.
The product operating temperature is used to monitor the
temperature of the product, and proper thermal conditions
can be veried by measuring the temperature at positions
P1, P2, P3 and P4. The temperature at these positions (T
P1
,
T
P2
, T
P3
, T
P4
) should not exceed the maximum temperatures
in the table below. The number of measurement points
may vary with different thermal design and topology.
Temperatures above maximum T
P1
, measured at the
reference point P1 (T
P3
/
P3
for base plate versions) are not
allowed and may cause permanent damage.
Denition of product operating temperature
Position Description Max temperature
P1
PWB (reference point, open
frame)
T
P1
=125º C
P2 Opto-coupler T
P2
=105º C
P3
PWB (reference point for
base-plate version)
T
P3
=125º C
P4 Primary MOSFET T
P4
=125º C
For more information, please visit the product page.