PQ48033QGA25NNS [SYNQOR]
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, QUARTER BRICK PACKAGE-8;
| 型号： | PQ48033QGA25NNS |
| 厂家： | 
SYNQOR WORLDWIDE HEADQUARTERS |
| 描述： | DC-DC Regulated Power Supply Module, 1 Output, Hybrid, QUARTER BRICK PACKAGE-8 |
| 文件： | 总14页 (文件大小：560K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EMI Characteristics
Application Note 00-08-02 Rev. 04 - 6/25/02
Summary:
This application note will give an overview of electromagnetic interfer-
ence (EMI), the appropriate standards and regulations, how these stan-
dards and regulations relate to dc/dc power modules, suggestions for
external filtering solutions, and suggested layout and grounding prac-
tices.
1.0 Introduction
Designing for electromagnetic compatibility (EMC) is one of the most difficult challenges for electronic system
designers. Almost all-electronic equipment is required to meet one or more EMC standards at the system or
product level. One of the most challenging subsystems when speaking about EMC is the power supply or in this
case the dc/dc power module. All modern dc/dc converters are composed of one or more switching stages
containing both pulsed voltages and currents, which generate a broad noise spectrum resulting in electromag-
netic interference (EMI).
This application note will give an overview of electromagnetic interference (EMI), the different standards and reg-
ulations, how these standards and regulations relate to dc/dc power modules, suggestions for external filtering
solutions, and suggested layout and grounding practices.
The first step in designing systems for EMI compliance is to understand that the different standards and regula-
tions do not directly apply to the dc/dc power module but to the overall system. Regardless, understanding and
minimizing the emissions emanating from the power module is a good beginning to EMI system compliance.
2.0 General Overview
Electromagnetic interference (more commonly known as EMI) refers to how different sets of electronic equipment
interact with each other, usually in a negative manner. The recent advances in semiconductor devices and large-
scale integration has dramatically reduced the size of electronic equipment while increasing the probability for
electromagnetic interference between the different systems and subsystems. Today's electronic designers must
make sure their solutions work in an environment of high EMI. It is not practical to ask new product designers
to test their equipment under all conditions and possible end-user configurations, therefore strict emissions regu-
lations have been established. In the United States the Federal Communications Commission (FCC) regulates the
use of radio and wire communications. Part of its responsibility concerns the control of electromagnetic inter-
ference. The standards for the allowed levels of electromagnetic emissions are outlined in part 15 of the FCC
rules and regulations. These rules apply to almost all-electronic equipment. Under these rules, limits are placed
on the maximum allowable radiated emissions in the frequency range between 30 to 1000 MHz and on the
maximum allowable conducted emissions on the AC power line in the frequency range of 0.450 to 30 MHz.
Radiated Emissions
Radiated emissions refer to interference that is coupled through the air. It is the belief of the FCC that at fre-
quencies below 30 MHz the primary cause of EMI occurs by allowing RF to flow through the AC power lines
where it subsequently radiates into neighboring equipment (conducted emissions).
Page 1
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
All electronic equipment that generates pulses of any kind in excess of 10,000 pulses per second (> 10 kHz)
is subjected to these regulations. Electronic equipment is divided into two classes according to the FCC:
•
Class A: Electronic equipment that is marked for use in a commercial, industrial, or
business environment [2].
•
Class B: Electronic equipment that is marketed for use in a residential environment,
notwithstanding its use in a commercial, industrial, or business environment [2].
Class B equipment is more likely to be located in close proximity to radio and television receivers, therefore,
the emissions limits for these devices is more restrictive relative to Class A. As it was stated before, compli-
ance is the responsibility of the end-product manufacturer.
Tables 1 and 2 show the different radiated emissions limits for both Class A and Class B. A true compari-
son of these limits cannot be made unless they are compared at the same distance. The Class A limits can
be extrapolated to a distance of 3-m by using a 1/r extrapolation where r is the distance between the source
and the receiving equipment. In general, Class B limits are more restrictive by a factor of 3 (~ 10 dB) as
shown in Figure 1.
Measuring
Distance (m)
Field Strength
(µV/m)
Frequency
(MHz)
30 - 88
88 - 216
30
30
30
30
50
70
216 - 1000
Table 1: FCC Class A Radiated Emmissions Limits [2].
Measuring
Distance (m)
Field Strength
(µV/m)
Frequency
(MHz)
30 - 88
88 - 216
3
3
3
100
150
200
216 - 1000
Table 2: FCC Class B Radiated Emmissions Limits [2].
Page 2
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
FCC Part 15, Subpart J radited emissions limits measured at
a distanace of 3-m
800
700
600
500
400
300
200
100
0
10
100
1000
Frequency (MHz)
Class B
Class A
Figure 1: Radiated emissions limits measured at a distance of 3.0m [1].
Conducted Emissions
Table 3 shows the conducted emission limits for both Class A and Class B type equipment. Conducted emissions
are measured as the voltage measured common-mode (+Vin to ground and -Vin to ground) on the power line
using a 50-ohm/50-µH line impedance stabilization network (LISN).
Frequency
(MHz)
Class A
Class B
(µV)
(µV)
0.45 – 1.6
1.6 - 30
1000
3000
250
250
Table 3: FCC Conducted Emmission Limits [2].
Standards
The International Special Committee on Radio Interference (CISPR) regulates the international community. CISPR
has no regulator authority, but its standards have been adopted by most European nations. Figure 2 shows a
comparison between the CISPR recommended radiated emission standard and the FCC limits. The FCC limits
have been scaled to a 10 m measuring distance for this comparison [1]. Figure 3 shows a similar comparison
for the conducted emission standards. The limits in Figures 2 and 3 are displayed in decibels relative to 1 µV.
The emission levels in decibels can be easily calculated using the following expression: emissions in decibels =
20 log (noise level voltage/1µV).
Page 3
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
FCC and CISPR Radiated Emission Limits
50
45
40
35
30
25
10
100
1000
Frequency (MHz)
FCC Class A
CISPR Class A
FCC Class B
CISPR Class B
Figure 2: Radiated emission limits measured at a distance of 10 m [1].
FCC and CISPR Conducted Emission Limits
75
70
65
60
55
50
45
40
0.1
1
10
100
Frequency (MHz)
FCC Class A
CISPR Class A
FCC Class B
CISPR Class B
Figure 3: Conducted emission limits [1].
FCC and CISPR also specify susceptibility emission limits of home electronics equipment and systems. To date,
the FCC does not regulate the susceptibility of electronic equipment; the FCC relies on self-regulation by the
industry. European nations are governed by the standards suggested by CISPR. Any product sold in Europe
must meet these requirements. All SynQor power modules are tested and meet IEC PUBL. 1000-4-3 limits. IEC
1000-4-3 test at field strengths of 3 V/m (normal performance) and 10 V/m (reduced performance). It has been
shown that field strength greater than 2 V/m occurs for approximately 1 % of the time [1].
Page 4
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
Another standard that is sometimes relevant is the EN300 386-2. This standard is relevant only for telecommu-
nications equipment and it applies to equipment with either AC or DC power mains. For systems with DC input
mains the EN300 386-2 standard specifies levels identical to the one specified by CISPR Class A limits.
However, the EN300 386-2 standard extends to lower frequencies (20 kHz - 150 kHz). All of the SynQor
power modules operate with switching frequencies in excess of 150 kHz. Therefore, typical power modules do
not affect the low frequency emission levels of the system.
3.0 EMC For Power Modules
The first step in tackling the EMI problem is a thorough understanding of the requirements and how it relates to
your system. Remember, there are no conducted or radiated emission restrictions that apply to power modules
as a stand-alone product. Power modules are considered one of many components of modern telecom or com-
puter equipment. The requirements apply to the system. The end product must meet a set of conducted and radi-
ated emission levels that depends on the equipment usage and country into which it is being sold. Due to the
fact that EMI is a system level requirement, it is not practical nor economical for high-power modules to meet
either the conducted and radiated limits as a stand-alone component. Most high-power modules supplied by
SynQor or any other manufacturer will probably not comply with the conducted and radiated limits specified by
the different standards without some effort in the design of the system to limit noise.
3.1 Conducted EMI
Most electronic equipment has only one interface with the power source. It is at this interface that the conduct-
ed emission standards apply. In most applications, power modules are usually isolated from the main power
source by EMI filters, circuit breakers, fuses, transient protection devices, DC/DC converters, and/or AC/DC
power converters. Therefore, in most applications the conducted emissions radiating from the power-module do
not appear directly at the power mains. It is very possible that the system will meet the conducted EMI limits
without any of the power modules meeting the EMC standard as a stand-alone component. Many systems will
meet all EMI standards by simply using a single EMI filter at the input of the power mains.
AC/DC and DC/DC converters by nature generate significant levels of both conducted and radiated noise.
Furthermore, if these noises are not suppressed close to the source, they can very easily couple to other areas
of the system, greatly
increasing the complexity
of
the
problem.
Vd = V1 - V2 = differential mode voltage component
Id = (I1 - I2) / 2 = differential mode current component
Vc = (V1 + V2) / 2 = common mode voltage component
Ic = I1 + I2 = common mode current component
Cs = effective parasitic capacitance between the dc/dc/ module
and the chassis ground
Therefore, it is recom-
mended to have some
level of EMI suppression
local to each power mod-
ule.
In order to better under-
stand the source of con-
ducted emissions, emis-
sions are generally classi-
fied as differential (sym-
metrical) or common
I1
Id
+
Ic/2
Vd
-
DC-DC
Module
I2
Ic/2
+
+
V1
Id
(asymmetrical)
mode
-
V2
noise. The definition of
common mode (CM) and
differential mode (DM)
voltages and currents is
illustrated in Figure 3.
Cs
-
Ic
Figure 3: Definition of differential and common mode currents and voltages.
Page 5
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
The natural operation of dc/dc converters results in differential mode type currents and voltages. SynQor has
added an input filter to all of its power modules to decrease the DM noise emitted by the converter. The com-
mon mode noise emitted by the module cannot be directly determined since there is no direct coupling mecha-
nism. The common mode current level is directly related to the effective parasitic capacitance between the power
module and chassis ground. SynQor's power modules utilize an open frame design with no baseplate and no
chassis ground connection. Not having a baseplate greatly reduces the effective capacitance between the mod-
ule and chassis ground. Therefore, common mode currents are greatly reduced relative to typical power mod-
ules.
Figures 4 and 5 show a comparison of how the SynQor power modules differ from the traditional dc/dc mod-
ule relative to their coupling mechanism for common mode emissions. Both of these figures present a simplified
version of the common mode emissions problem in dc/dc modules. It is well known that there are many differ-
ent coupling mechanisms between the power module and chassis ground. But at the same time as power sup-
ply designers, we recognize that the semiconductor devices in conjunction with the power transformer represent
the major sources of common mode voltages and currents. Figure 4 shows the traditional implementation of
high-power dc/dc modules. Capacitance Cs1 represents the effective parasitic capacitance between the base-
plate and chassis ground. Capacitance Cs1 is usually very small, its value is directly related to the size of the
baseplate, the proximity of the baseplate to chassis ground, and the size and shape of the chassis ground. In
many high-power modules the baseplate is directly connected to chassis ground shorting capacitance Cs1.
Capacitance Cs2 is the parasitic capacitance between the semiconductor devices and the baseplate. In order
to maximize the thermal performance of the module, in the traditional solution, a very thin thermal pad sepa-
rates the "tab" of the semiconductor devices and the baseplate. This type of construction results in significant
parasitic capacitance between the semiconductors and the baseplate. Capacitance Cs2 provides an easy cou-
pling mechanism for common mode currents to flow into the chassis ground, especially when the baseplate is
connected to chassis ground.
Baseplate
Cs1
Baseplate
Cs2
Thermal Pad
Semiconductor
Devices
Cs1 - parasitic capacitance between baseplate and chassis
Cs2 - parasitic capacitance between semiconductor and baseplate
Figure 4: Traditional physical design for high power dc/dc modules.
Page 6
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
Figure 5 shows the physical solution of the SynQor power module. The preferred solution does not have a base-
plate (Cs1 = 0). Capacitance Cs2 is the effective parasitic capacitance between the semiconductors and chas-
sis ground. This capacitance is small relative to the traditional physical implementation, resulting in reduced
common mode emissions.
Semiconductor
Devices
Cs2
FR4 Multilayer Board
Integrated
Magnetics
Cs2 - parasitic capacitance between semiconductor(s) and chassis ground
Figure 5: Physical design of a typical SynQor dc/dc module.
SynQor offers a baseplate option on all of their modules (Figure 6). In this implementation, capacitance Cs2,
which represents the effective capacitance between the semiconductor devices and the baseplate, again, is sig-
nificantly smaller when compared to the traditional design. It is the proximity of the metal "tab" of the semi-
conductor devices to the base plate that contributes to increased coupling (increased Cs2) and increased com-
mon mode currents in the traditional arrangement. Therefore, SynQor's dc/dc power modules generate reduced
levels of common mode emissions.
Baseplate
Semiconductor
Devices
Thermal
Compound
Cs1
Baseplate
Cs2
FR4 Multilayer Board
Integrated
Magnetics
Cs1 - parasitic capacitance between baseplate and chassis
Cs2 - parasitic capacitance between semiconductor and baseplate
Figure 6: Physical design of a SynQor module with the baseplate option.
Page 7
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
Table 4 summarizes the EMC related characteristics of selected SynQor modules. Please consult the individual
datasheet for specific data on each module. The switching frequency is listed to help understand the noise spec-
trum and help in the design of an external filter. It is important to note that the switching frequency of the mod-
ules has a tolerance of +/- 17 % over temperature. The table summarizes the characteristics of the input filter.
Most modules have a Pi type filter at the input. C1 is the capacitance connected directly at the input pins. C2
is the second capacitor of the Pi filter. In all of the SynQor modules, the inductor is located in the +Vin lead.
Nominal
Input
Capacitance
C1, C2 (µF)
Input
Inductor
(µH)
Operating
Frequency
(kHz)
Module Type
Input Filter
PQ48150QGA06NNS
PQ48120QGA08NNS
PQ48060QGA17NNS
PQ48050QGA20NNS
PQ48033QGA25NNS
PQ48025QGA25NNS
PQ48020QGA25NNS
PQ48018QGA25NNS
PQ48015QGA25NNS
PQ48050HTA33NNS
PQ48033HTA50NNS
PQ48025HTA60NNS
PQ48020HTA60NNS
PQ48018HTA60NNS
PQ48015HTA60NNS
270
215
215
300
240
200
270
240
200
200
260
200
200
200
260
2nd order
2nd order
2nd order
2nd order
2nd order
2nd order
2nd order
2nd order
2nd order
Pi
0, 2.46
0, 2.46
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.1
4.1
4.1
4.1
4.1
4.1
0, 2.46
0, 2.46
0, 2.46
0, 2.46
0, 2.46
0, 2.46
0, 2.46
1.64, 3.28
1.64, 3.28
1.64, 3.28
1.64, 3.28
1.64, 3.28
1.64, 3.28
Pi
Pi
Pi
Pi
Pi
Table 4: EMC characteristics of the SynQor power modules. Refer to individual technical
datasheets for information on specific modules.
Figures 7, and 8 show the conducted emissions of the 25A quarter-brick and the 50A half-brick 3.3V modules
operating at full load with the aid of an external filter. The modules were tested in an independent Lab (KTL of
Dallas) in accordance with the accepted CISPR standards. The modules were loaded with a passive resistive
load to avoid any possible interaction between the "dynamic load" and the module. The units were mounted
on a four layer test board where the bottom layer was used for a chassis ground plane. The results show peak
measurements relative to the average Class B (CISPR) limits. The implementation of the two external filters used
is summarized in Figure 9. The suggested filters allow for the modules to meet CISPR Class B conducted emis-
sions limits. Capacitors CYS1 and CYS2 are added to minimize the electromagnetic interference emanating
from the output cables in the 5 to 30 MHz frequency range. These capacitors could be omitted if the output dis-
tribution bus is relatively short in length.
Page 8
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
Figure 7a: Conducted emission from 150 kHz to 600 kHz for the 25A quarter-brick using the
EMI filter shown in Figure 9a [6]. The data shown corresponds to the emission meas-
ured in the positive input lead. The 50-dBµV level is shown as a reference.
Figure 7b: Conducted emission from 500 kHz to 30 MHz for the 25A quarter-brick using the
EMI filter shown in Figure 9a [6]. The data shown corresponds to the emission meas-
ured in the positive input lead. The 50-dBµV level is shown as a reference.
Page 9
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
Figure 8a: Conducted emission from 150 kHz to 600 kHz for the 50A half-brick using the EMI
filter shown in Figure 9b [6]. The data shown corresponds to the emission measured
in the positive input lead. The 60-dBµV level is shown as a reference.
Figure 8b: Conducted emission from 500 kHz to 30 MHz for the 50A half-brick using the EMI
filter shown in Figure 9b [6]. The data shown corresponds to the emission measured
in the positive input lead. The 60-dBµV level is shown as a reference.
Page 10
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
Filter Mod. # 4
CYS2
CY2
PQ48033QGA25NNS
DC/DC Converter
C
CD2
CD1
L1
E
Rload
CY1
CYS1
CY1 = CY2 = CYS1 =CYS2 = 2700 pF /2000V ceramic capacitor from AVX
CD1 = CD2 = 3 x 1µF /100V ceramic capacitor from AVX
L1 = inductor (Pulse part# P0422)
C = 33µF /100V electrolytic capacitor, Refer to “Input System Instability” application note for details.
E
Iout = 25 Amps
Figure 9a: External filter used with the PQ48033QGA25NNS (quarter-brick 25A/3.3V)
power module.
Filter Mod. # 5
CYS2
CYS1
CY2
CY1
CD1
L1
PQ48033HTA50NNS
DC/DC Converter
CD3
Rload
L2
CD2
C
E
CY1 = CY2 = CYS1 =CYS2 = 2700 pF /2000V ceramic capacitor from AVX
CD1 = CD2 = CD3 = 2 x 1µF /100V ceramic capacitor from AVX
L1 = inductor (Pulse part# P0353)
C = 33µF /100V electrolytic capacitor
E
Iout = 50 Amps
Figure 9b: External filter used with the PQ48033HTA50NNS (half-brick 50A/3.3V)
power module.
Page 11
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
3.2 Radiated EMI
Again it is important to remember that only the system needs to meet the required standards. Radiated emis-
sions are of importance in the 30 MHz to 1000 MHz range. Metal enclosures in addition to power and ground
planes provide significant attenuation to electromagnetic emissions in the frequency range in question.
Therefore, most physical system solutions will provide enough attenuation and allow the system to meet radiat-
ed emission standards with relative ease. It is neither practical nor economical to demand the typical dc/dc
module to meet radiated EMC standards as a stand-alone product.
A one-piece metal "box" with no opening or cracks would be the ideal shield to radiated noise, but this is not
a practical solution. When designing for radiated emissions it is important to minimize the size of any opening
in the chassis box. The size of any opening in addition to its location relative to the source of radiated EMI is
of great importance as it concerns radiated EMI. Furthermore, any location where two or more metal pieces of
the chassis box meet needs to make electrical contact to maintain the integrity of the shield.
Again, radiated emissions are classified into differential and common mode depending on the source.
Differential-mode noise radiates from small loop antennas. Loop antennas can be defined as the area enclosed
by a current carrying loop. The magnitude of the field is proportional to the magnitude of the current, the
enclosed area, and the square of the oscillating frequency. Reducing the area enclosed by any current loop can
easily minimize differential-mode noise. Great care has been taken in the layout of all SynQor power modules
to reduce differential mode radiation.
On the other hand, common-mode radiation is harder to control and usually determines the overall radiated emis-
sion performance of the product. Common-mode radiation usually emanates from the input and output cables.
Due to their relatively long length, input and output mains are good transmitters of EMI noise. Input and output
cables behave as monopole antennas driven by a voltage. Decoupling both input and output mains with ceram-
ic capacitors to chassis ground close to the power module suppresses the excitation voltage. Great care has to
be taken not to exceed the leakage current requirement (this is a safety requirement) when adding capacitors
from any point to chassis ground in systems powered by an AC distribution.
For reference, Table 5 shows radiated emissions levels for a 25A quarter-brick 3.3Vout module operating at full
load. The module was tested with the external filter suggested in Figure 9a in place. Again, a resistive load
bank was used to obtain these results. The tables show peak measurements of the radiated emissions levels rel-
ative to the average Class B limits as suggested by CISPR. The data shows that the module and filter combina-
tion fails CISPR Class B emissions standards by only a few dBs. The module was tested in an outdoor inde-
pendent test facility at KTL of Dallas.
The conducted and radiated emissions levels reported for the different modules should be used as a reference
only. The emissions levels are very dependent on the physical configuration and grounding practices of the sys-
tem under test.
Page 12
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
Antenna
Polarization (dBµV/m)
Reading
Class B limit
(dBµV/m)
Diff.
(dB)
Type of
Measurement
Frequency
(MHz)
30.17
30.66
36.20
37.71
48.76
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
30.9
1.929.7
1.637.1
37.8
28.7
31.2
23.4
27.5
43.5
43.5
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
0.9
-0.3
7.1
7.8
-1.3
1.2
-6.6
-2.5
13.5
13.5
2.8
Peak
Peak
Peak
Peak
Peak
Peak
Peak
Peak
Peak
Peak
Peak
Peak
Peak
Peak
Peak
52.03
86.46
108.80
141.28
142.80
160.38
165.13
208.90
221.90
228.48
32.8
32.5
29.2
27.4
2.5
-0.8
-2.6
-1.9
28.1
36.20
36.20
37.75
37.75
50.30
50.30
52.03
62.84
74.60
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
48.2
32.4
48.0
32.4
40.5
25.5
36.3
33.8
28.2
31.1
35.5
36.1
41.8
32.3
42.4
32.4
30.1
28.1
26.3
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
30.0
18.2
2.4
18.0
2.4
10.5
-4.4
6.3
3.8
-1.8
1.1
5.5
6.1
11.8
2.3
12.4
2.4
0.1
-1.9
-3.7
Peak
Quasi-Peak
Peak
Quasi-Peak
Peak
Quasi-Peak
Peak
Peak
Peak
Peak
Peak
Peak
Peak
85.96
119.13
125.40
142.50
142.50
144.00
144.00
165.10
208.80
224.90
Quasi-Peak
Peak
Quasi-Peak
Peak
Peak
Peak
302.57
343.57
377.50
H
H
H
26.0
27.8
25.1
37.0
37.0
37.0
-11.0
-9.2
-11.9
Peak
Peak
Peak
301.87
334.08
438.00
V
V
V
23.0
19.9
22.6
37.0
37.0
37.0
-14.0
-17.1
-14.4
Peak
Peak
Peak
Table 5: Radiated emissions of a 25A Quarter-brick 3.3V module with the external filter
shown in Figure 9a.
Page 13
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
Application Note 00-08-02 Rev. 04
EMI Characteristics
4.0 Layout and Grounding Practices
Great care should be taken in the layout and grounding practices used for the module and system in general.
A list of suggestions that will minimize conducted and radiated emissions include:
1. Add both, low frequency tantalum and high frequency ceramic capacitors to the dc/dc
module output bus. Place at least one of each as close as possible to the output termi-
nals of the module.
2. Add both, low frequency electrolytic and high frequency ceramic capacitor to the dc
input distribution bus. Place at least one of each as close as possible to the input ter-
minals of the module.
3. Use short leads on all filter and decoupling components. Minimize all circuit loops that
carry significant current.
4. Minimize parasitic inductances by using wide distribution traces over ground planes.
5. Place a Y-capacitor between input and output ground planes. Return all common mode
noise to the input ground.
Additional details about all of these topics can be found in [1,4].
5.0 References
[1] Ott, Henry, W., Noise Reduction Techniques in Electronic Systems, Second Edition, John Wiley & Sons, New
York, 1988.
[2] Code of Federal Regulations, Title 47 (47CFR). Part 15, Subpart J. "Computing Devices."
[3] CISPR, Publication 22. "Limits and Methods of Measurements of Radio Interference Characteristics of
Information Technology Equipment," 1985.
[4] Thihanyi, Laszlo, Electromagnetic Compatibility in Power Electronics, 10th edition, J. K. Eckert & Company,
Inc., Sarasota, Florida, 1995.
[5] Ferreira, J.A., Winlock, P.R., and Holm, S.R., "Sources, Paths and Traps of Conducted EMI in Switch Mode
Circuits,"
[6] KTL Engineering test report # 0L0073EUS
155 Swanson Rd., Boxboro, MA 01719
Phone: 978-849-0600
Toll Free: 888-567-9596
Fax: 978-849-0602
Web: www.synqor.com
e-mail: sales@synqor.com
Author: Richard Farrington
Page 14
SynQor - Advancing the Power Curve
• 888-567-9596 • www.synqor.com
相关型号：
PQ48033QGA25NNS-G
DC-DC Regulated Power Supply Module, 1 Output, 82.5W, Hybrid, ROHS COMPLIANT PACKAGE-8
SYNQOR
PQ48033QGA25NRS
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, QUARTER BRICK PACKAGE-8
SYNQOR
PQ48033QGA25NRS-G
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, ROHS COMPLIANT PACKAGE-8
SYNQOR
PQ48033QGA25NYA
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, QUARTER BRICK PACKAGE-8
SYNQOR
PQ48033QGA25PKA
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, QUARTER BRICK PACKAGE-8
SYNQOR
PQ48033QGA25PNS
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, QUARTER BRICK PACKAGE-8
SYNQOR
PQ48033QGA25PRA
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, QUARTER BRICK PACKAGE-8
SYNQOR
PQ48033QGA25PRS
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, QUARTER BRICK PACKAGE-8
SYNQOR
PQ48033QGA25PYA
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, QUARTER BRICK PACKAGE-8
SYNQOR
PQ48033QGA25PYS
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, QUARTER BRICK PACKAGE-8
SYNQOR
©2020 ICPDF网 联系我们和版权申明