Datasheet
ULS 100-Watt Series
Sixteenth-brick DOSA-Compatible,
Isolated DC-DC Converters
MDC_ULS-100 Series.A09 Page 13 of 28
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Emissions Performance, Model ULS-5/20-D48
Murata Power Solutions measures its products for radio frequency emissions
against the EN 55022 and CISPR 22 standards. Passive resistance loads are
employed and the output is set to the maximum voltage. If you set up your
own emissions testing, make sure the output load is rated at continuous power
while doing the tests.
The recommended external input and output capacitors (if required) are
included. Please refer to the fundamental switching frequency. All of this
information is listed in the Product Specifi cations. An external discrete fi lter is
installed and the circuit diagram is shown below.
[1] Conducted Emissions Parts List
[2] Conducted Emissions Test Equipment Used
Hewlett Packard HP8594L Spectrum Analyzer –S/N 3827A00153
2Line V-networks LS1-15V 50/50Uh Line Impedance Stabilization Network
[3] Conducted Emissions Test Results
[4] Layout Recommendations
Most applications can use the fi ltering which is already installed inside the
converter or with the addition of the recommended external capacitors. For
greater emissions suppression, consider additional fi lter components and/or
shielding. Emissions performance will depend on the user’s PC board layout,
the chassis shielding environment and choice of external components. Please
refer to Application Note GEAN02 for further discussion.
Since many factors affect both the amplitude and spectra of emissions, we
recommend using an engineer who is experienced at emissions suppression.
Contact Murata Power Solutions for Class B Emissions test circuit and con-
ducted emissions performance test results.
Reference
Reference
Part Number
Part Number
Description
Description
Vendor
Vendor
C1
GRM32ER-
72A105KA01L
SMD CERAMIC-100V-
1000nF-X7R-1210
Murata
C2
GRM-
319R72A104KA01D
SMD CERAMIC
100V-100nF-±10%-
X7R-1206
Murata
L1
LB16H1324
COMMON MODE-
1320uH-±25%-4A-R5K-
21*21*12.5mm
High
Light
C4, C5
GRM-
32DR73A223KW01L
SMD CERAMIC
1000V-0.022uF-±10%-
X7R-1210
Murata
C3
UHE2A221MHD
Aluminum 100V-320Uf-
±10%-long lead
Nichicon
C6
NA
Graph 3. Conducted emissions performance, Positive Line,
CISPR 22, Class A, 48Vin, full load
Graph 4. Conducted emissions performance, Negative Line,
CISPR 22, Class A, 48Vin, full load
C1
L1
C2 C3
C4 C5
DC/DC
C6
++
-48V
RTN
GND
VCC
GND
Load
Figure 4. Conducted Emissions Test Circuit