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EN/LZT 146 035 R3D Ericsson Power Modules, June 2005
PKM 4000C Datasheet
EMC Specication
The conducted EMI measurement was performed using a
module placed directly on the test bench.
The fundamental switching frequency is 150kHz.
Conducted EMI Input termonal value (typ) .
External lter (class B)
Required external input lter in order to meet class B in
EN 55022, CISPR 22 and FCC part 15J.
The capacitors are ceramic type. Low ESR is critical for
achieveing these results.
Test set-up.
Layout Recommendation
The radiated EMI performance of the DC/DC converter will
be optimised by including a ground plane in the Pcb area
under the DC/DC converter.
This approach will return switching noise to ground as di-
rectly as possible, with improvements to both emissions and
susceptibility.
If one ground trace is used, it should be connected to the
input return. Alternatively, two ground traces may be used,
with the trace under the input side of the DC/DC converter
connected to the input return and the trace under the output
side of the DC/DC converter connected to the output return.
Make sure to use appropriate safety isolation spacing be-
tween these two return traces. The use of two traces as de-
scribed will provide the capability of routing the input noise
and output noise back to their respective returns.
PKM 4118GC without lter.
PKM 4118GC with lter.
Output ripple and noise test setup
Output ripple and noise
The circuit below has been used for the ripple and noise
measurements on the PKM 4000C Series DC/DC converters.
DC
Power
Source
+
-
5H 50
5H 50
LISN
in
out
rcvr
50 ohm input
1 m Twisted Pair
50 ohm temination
Optional Connection
to Earth Ground
Filter
(if used)
Power Module
Resistive
Load
Printed Circuit Board
EMC
Reciver
Computer
BNC
Connector
to Scope
Ceramic
Capacitor
+Vout
+Sense
Trim
-Sense
-Vout
Load
Tantalum
Capacitor
* Conductor from Vout to capacitors = 50mm [1.97in]
+
0.1uF
10uF