Data Sheet
October 2009
FLTR75V05 Filter Module
75 Vdc Input Maximum, 5 A Maximum
Features
RoHS Compliant
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Compatible with RoHS EU Directive 200295/EC
Compatible in Pb- free or SnPb reflow environment
Small size: 25.4 mm x 25.4 mm x 10.2 mm
(1.0 in. x 1.0 in. x 0.4 in.)
Optimized for use with high-frequency switching
dc-to-dc power modules
Printed-circuit board mountable
Operating case temperature range:
–40 °C to +100 °C
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Options
Applications
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Choice of pin lengths
Common-mode and differential-mode filtering of
power supply dc input and output lines
Distributed power architectures
Telecom
Datacom
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Description
The FLTR75V05 Filter Module is designed to reduce the conducted common-mode and differential-mode noise
on input or output lines of high-frequency switching power supplies. The module has a maximum current rating
of 5 A. It provides high insertion loss throughout the frequency range regulated by the U.S. Federal Communi-
cations Commission (FCC) and the International Special Committee on Radio Interference (CISPR) for con-
ducted emissions.
The module is 25.4 mm long, 25.4 mm wide, and 10.2 mm high (1.0 in. x 1.0 in. x 0.4 in.) and mounts on a PC
board in a natural convection or forced-air environment.
FLTR75V05 Filter Module
75 Vdc Input Maximum, 5 A Maximum
Data Sheet
October 2009
Introduction
High-density power modules are usually designed to operate at a high switching frequency to reduce the size of
the internal filter components. The small EMI filters internal to the modules are often inadequate to meet stringent
international EMI requirements. Many high-density electronic packaging techniques can increase the noise con-
ducted onto the modules’ input and output lines. For example, the close proximity of switching components to the
input pins increases internal noise coupling; and planar transformers, designed to handle high-power levels in low-
profile packages, have high interwinding capacitance that can increase common-mode current levels. Also, metal
substrates used to facilitate heat transfer from the power train components to an external heat sink add to com-
mon-mode noise because of the large capacitance between switching components and the metal substrate.
Many international agencies specify conducted and radiated emissions limits for electronic products. Included
among these are CISPR, FCC, VCCI, and the new CE specifications. Most agency-conducted noise limits apply
only to noise currents induced onto the ac power lines in finished products. European Telecommunication Standard
Instructions (ETSI) are an exception, applying CE requirements to dc supplies with cables over three meters long.
Although not required to do so by agency standards, some system designers apply the conducted emissions
requirements to subassemblies within the product to reduce internal interference between subsystems and to
reduce the difficulty of meeting overall system requirements.
To meet these requirements, external filtering of the power module is often required. When used in conjunction with
the recommended external components and layout, the
Lineage Power
filter module will significantly reduce the
conducted differential and common-mode noise returned to the power source. CISPR and FCC class B require-
ments can be met by using the filter as described in the following sections.
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are abso-
lute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the operations sections of the data sheet. Exposure to absolute maximum ratings for extended
periods can adversely affect device reliability.
Parameter
Input Voltage:
Continuous
Transient (100 ms)
Voltage from GND to Either Input Lead
Operating Case Temperature
Storage Temperature
Symbol
V
I
V
I, trans
—
T
C
T
stg
Min
—
—
—
–40
–55
Max
75
100
1500
100
125
Unit
Vdc
V
Vdc
°C
°C
2
Lineage Power
Data Sheet
October 2
FLTR75V05 Filter Module
75 Vdc Input Maximum, 5 A Maximum
The GND pin of the filter module is attached to Y caps
within the module. This pin should be tied to a quiet
chassis ground point away from the power modules.
GND of the filter module should not be tied to the
CASE pin of the power module since this is a noisy
node and will inject noise into the filter, increasing the
input common-mode noise.
If no quiet grounding point is available, it is best to
leave the filter module GND pin unattached. Each
power system design will be different, and some exper-
imentation may be necessary to arrive at the best con-
figuration.
Figure 5 shows a typical schematic of a power module
with filter module and recommended external compo-
nents. Figure 6 is a proposed layout. More than one
power module may be attached to a single filter module
as long as input current does not exceed 5 A. Figure 7
shows the recommended schematic for two power
modules attached to a single filter.
In applications where the addition of input to output
capacitors is undesirable, do not use C3 and C4 shown
in Figures 5 and 6, and do not use C3, C4, C8, and C9
shown in Figure 7.
In –48 V applications where the shield plane and the
power module case must be tied to a signal, remove
C1 in Figures 5 and 6, remove C1 and C6 in Figure 7,
and connect the shield plane and CASE pin to the V
I
(+)
plane.
In +48 V applications where the shield plane and the
power module case must be tied to a signal, remove
C2 in Figures 5 and 6, remove C2 and C7 in Figure 7,
and connect the shield plane and CASE pin to the V
I
(–)
plane.
Application
Conducted noise on the input power lines can occur as
either differential-mode or common-mode noise cur-
rents. Differential-mode noise is measured between the
two input lines, and is found mostly at the low-
frequency end of the spectrum. This noise shows up as
noise at the fundamental switching frequency and its
harmonics. Common-mode noise is measured
between the input lines and ground and is mostly
broadband noise above 10 MHz. The high-frequency
nature of common-mode noise is mostly due to the
high-speed switching transitions of power train compo-
nents. Either or both types of noise may be covered in
a specification, as well as a combination of the two. An
approved measurement technique is often described,
as well.
Differential-mode noise is best attenuated using a filter
composed of line-to-line capacitors (X caps) and series
inductance, provided by either a discrete inductor or
the leakage inductance of a common-mode choke. In
addition to the differential filtering provided by the filter
module, it is recommended that an electrolytic capaci-
tor be located at the converter side of the filter to pro-
vide additional attenuation of low-frequency differential
noise and to provide a low source impedance for the
converter, preventing input filter oscillations and load-
transient induced input voltage dips.
Common-mode noise is best attenuated by capacitors
from power module input to power module output,
capacitors from each input line to a shield plane
(Y caps), and common-mode chokes. It is recom-
mended that ceramic capacitors be added around each
power module from each input and output pin to a
shield plane under the module. The shield plane should
be connected to the CASE pin.
Lineage Power
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