Datasheet

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ULS 30-Watt Series
Sixteenth-brick DOSA-Compatible,
Isolated DC/DC Converters
MDC_ULS-30W_C07 Page 29 of 30
Emissions Performance
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
Rohde & Schwarz EMI Test Receiver (9KHz – 1000MHz) ESPC
Rohde & Schwarz Software ESPC-1 Ver. 2.20
HP11947A Transient Limiter (Agilent)
OHMITE 25W – Resistor combinations
DC Source Programmable DC Power Supply Model 62012P-100-50
[3] 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 GEAN-02 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.
[4] Conducted Emissions Test Results
Reference Part Number Description Vendor
L1 PE-62913 1mH, 6A Pulse
L2 NC 4.7uH, 3.6A Murata
C1, C2 VZ Series
Ceramic Capacitor
(3.2uf) = 2.2ufd/1ufd in
parallel, 100V
Panasonic
C3 VZ Series
Qty 2 - Electrolytic Capacitor
22ufd, 100V
Panasonic
C4, C5 Unknown 3.3nF, 1500V Unknown
C6 VZ Series
Electrolytic Capacitor 33ufd,
100V
Panasonic
C2
L1
C6C3C1
Vin+ Vout+
Vout-Vin-
Black
DC Source
Resistive Load
inside a metal
container
Test Card
UUT
Resistive Load
V-
V+
L2
C5
C4
Figure 9. Conducted Emissions Test Circuit
Graph 1. ULS-3.3/8-D48N-C conducted emissions performance, Peak Detection Mode,
CISPR/EN55022, Class B, full load at 48Vin
Graph 2. ULS-12/2.5-D48N-C conducted emissions performance, Peak Detection Mode,
CISPR/EN55022, Class B, full load at 48Vin
Graph 3. ULS-15/2-D48P-C conducted emissions performance, Peak Detection Mode,
CISPR/EN55022, Class B, full load at 48Vin