Datasheet

cui.com
date 11/07/2014 │ page 20 of 36CUI Inc │ SERIES: NQB-D │ DESCRIPTION: FULLY REGULATED ADVANCED BUS CONVERTERS
EMC Specification
Conducted EMI Input terminal value (typ)
Conducted EMI measured according to EN55022, CISPR
22 and FCC part 15J (see test set-up). The fundamental
switching frequency is 140 kHz for NQB at V
I
= 53 V, max
I
O
.
EMI without filter
Suggested external input lter in order to meet class B
in EN 55022, CISPR 22 and FCC part 15J.
Optional external lter for class B
L1
C1 C2 C3
C4
C5
R
-
+
Module
+
-
0
0
L2
Filter components:
C1 = 1 μF
C2 = 1 μF+220 μF
C3 = 1 μF+220 μF
C4,C5 = 2.2 nF
L1 = 810 μH
L2 = 810 μH
EMI with filter
Test set-up
The radiated EMI performance of the product will
depend on the PWB layout and ground layer design.
It is also important to consider the stand-off of
the product. If a ground layer is used, it should
be connected to the output of the product and the
equipment ground or chassis.
A ground layer will increase the stray capacitance
in the PWB and improve the high frequency EMC
performance.
Layout recommendations
Output ripple and noise measured according to gure
below.
Output ripple and noise
Output ripple and noise test setup
For more information, please visit the product page.