
BWR-5/700-D48A
–INPUT
+INPUT
+5V OUT
–5V OUT
COMMON
10F
–5V
LOAD
10F
+5V
LOAD
–INPUT
+INPUT
GND
FLT-100V10
OUTPUT
UWR-5/1800-D48A
–INPUT
+INPUT
+5V OUT
COMMON
OUTPUT
6.8F
+5V
LOAD
–INPUT
+INPUT
GND
FLT-100V10
Output Ripple and Noise of BWR-5/700-D48A
(Using single leg of FLT-100V10 and 10F capacitance.)
20mV/div, 20MHz Bandwidth
Output Ripple and Noise of BWR-5/700-D48A
(No external capacitance.)
20mV/div, 20MHz Bandwidth
Figure 5. Using FLT-100V10 as an output Filter for Bipolar DC/DC
Figure 4. Using FLT-100V10 as an output Filter for Unipolar DC/DC
operating Temperature
Both the FLT-100V10 and FLT-100V20 are guaranteed for operation up to
+100°C case temperature. Performance graphs (see typical performance
curves) are provided for both models that depict the case temperature rise
versus average current for various air flow conditions.
on/off Control and external Fusing
To eliminate any current-path bypassing of the filter, the on/off control
circuitry used to control the DC/DC converter should be referenced to the
–Input pin of the converter and not to the –Input of the filter. The FLT-100V
series filters do not provide internal fusing, therefore An external fuse of
appropriate DC/DC rating should be provided externally.
Using a Single Filter with Multiple Converters
A single FLT-100V series filter can be used with multiple DC/DC converters
provided that the maximum rated current is observed. The use of common-
mode chokes in the design of these filters, however, requires that the +Input
current and –Input current be equal. A small imbalance in these currents
may cause the inductor to saturate and degrade the filter’s performance.
input Capacitor
FLT-100V series fi lters incorporate an internal, multi-layer film polymer
capacitor between the input lines for differential-mode noise filtering. This
telecom/datacom preferred capacitor provides electrical stability under both
AC and DC current loads. The capacitors insulation resistance tends to
improve under the stresses of heat and voltage. A typical ESR of 6 milli-
OHMs @ 500kHz, provides the necessary low impedance for high frequency
input current handling.
Using FLT-100V as an output Filter
Although optimized for use an input conducted emissions filter, the FLT-100V
series can be used as an output filter for DC/DC converters to reduce output
ripple and attenuate high frequency noise. Figures 4 and 5 show the recom-
mended connections for both unipolar and bipolar applications. Depending
upon application and desired performance, the Gnd pin connection can be
made at the output return, case shield plane, or left fl oating.Output ripple
and noise improvements are shown in the following illustrations for a typical
DC/DC converter that is using the setup shown in Figure 5.
FLT Series
Filter Modules, 100Vdc, 10 Amp and 20 Amp
Differential/Common-Mode Filters
Technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000
www.murata-ps.com
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