A KYOCERA GROUP COMPANY
AVX
Multilayer Ceramic Feedthru
Chip Capacitors And Arrays
Feedthru 0805/1206 Capacitors
Table of Contents
W2F/W3F Series - 0805 & 1206 Feedthru Chips . . . . . . . . . . . . . . . . . . . . . . . . . . 1
W2H/W3H Series - High Current Feedthru Capacitors . . . . . . . . . . . . . . . . . . . . 5
W3F4 Series - 4 Element 1206 Feedthru Array . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
W2F/W3F/W3F4 Series - Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
W2H/W3H Series - Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
W2F/W3F/W3F4 Series - Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1
Feedthru 0805/1206 Capacitors
W2F/W3F Series
W3 F 1 5 C 223 8 A T 3 A
Style Size Feedthru Number Voltage* Dielectric Capacitance Capacitance Failure Terminations Packaging Code Quantity Code
2=0805 of 1=100v A=NP0 Code Tolerance Rate T=Plated (Reel Size) (Pcs./Reel)
3=1206 Elements 5=50v C=X7R 8=+50/-20% A=Not 1=7" Reel F=1,000
Applicable Embossed Tape A=2,000,
3=13" Reel 4,000 or
Embossed Tape 10,000
*Note: NP0 available in 100V only and X7R available in 50V only.
GENERAL DESCRIPTION
Available in both a standard 0805 and 1206 size, AVX’s line
of feedthru capacitors are ideal choices for EMI suppres-
sion, broadband I/O filtering, or Vcc power line condition-
ing. The unique construction of a feedthru capacitor pro-
vides low parallel inductance and offers excellent decou-
pling capability for all high di/dt environments and provides
significant noise reduction in digital circuits to <5 GHz. A
large range of capacitor values are available in either NP0
or X7R ceramic dielectrics.
PERFORMANCE CHARACTERISTICS
CAPACITOR VALUES
NP0 X7R
Capacitance Tolerance
+50%, -20% +50%, -20%
Voltage Rating 100V 50V
Current Rating 300mA 300mA
Insulation Resistance 1000MΩ1000MΩ
DC Resistance <0.6Ω<0.6Ω
Operating Temperature Range -55 to +125°C
SIGNAL LINE - INPUT OUTPUT
GROUND
W2F Series
0805
W3F Series
1206
Part Number Size Voltage Dielectric Capacitance
W2F11A 220 8ATxx 0805 100V NP0 22pF
W2F11A 470 8ATxx 0805 100V NP0 47pF
W2F11A 101 8ATxx 0805 100V NP0 100pF
W2F11A 221 8ATxx 0805 100V NP0 220pF
W2F11A 471 8ATxx 0805 100V NP0 470pF
W2F15C 102 8ATxx 0805 50V X7R 1000pF
W2F15C 222 8ATxx 0805 50V X7R 2200pF
W2F15C 472 8ATxx 0805 50V X7R 4700pF
W2F15C 103 8ATxx 0805 50V X7R 10000pF
W2F15C 223 8ATxx 0805 50V X7R 22000pF
W2F15C 473 8ATxx 0805 50V X7R 47000pF
W3F11A 220 8ATxx 1206 100V NP0 22pF
W3F11A 470 8ATxx 1206 100V NP0 47pF
W3F11A 101 8ATxx 1206 100V NP0 100pF
W3F11A 221 8ATxx 1206 100V NP0 220pF
W3F11A 471 8ATxx 1206 100V NP0 470pF
W3F15C 102 8ATxx 1206 50V X7R 1000pF
W3F15C 222 8ATxx 1206 50V X7R 2200pF
W3F15C 472 8ATxx 1206 50V X7R 4700pF
W3F15C 103 8ATxx 1206 50V X7R 10000pF
W3F15C 223 8ATxx 1206 50V X7R 22000pF
W3F15C 473 8ATxx 1206 50V X7R 47000pF
HOW TO ORDER
2
Feedthru 0805/1206 Capacitors
W2F/W3F Series
T
P
LC
P
SW
BW
T
SX
L
C
L
EW
W
BL
Feedthru Pad Feedthru Pad
Common Ground
Common Ground
DIMENSIONS
RECOMMENDED SOLDER PAD LAYOUT (TYPICAL DIMENSIONS)
LWTBWBL EWXS
0805 MM 2.01 ± 0.20 1.25 ± 0.20 1.14 Max. 0.46 ± 0.10 0.18 + 0.25 -0.08 0.25 ± 0.13 1.02 ± 0.10 0.23 ± 0.15
(in.) (0.079 ± 0.008) (0.049 ± 0.008) (0.045 Max.) (0.018 ±0.004) (0.007 + 0.010 -0.003) (0.010 ± 0.005) (0.040 ± 0.004) (0.009 ± 0.006)
1206 MM 3.20 ± 0.20 1.60 ± 0.20 1.27 Max. 0.89 ± 0.10 0.18 + 0.25 -0.08 0.38 ± 0.18 1.60 ± 0.10 0.46 ± 0.15
(in.) (0.126 ± 0.008) (0.063 ± 0.008) (0.050 Max.) (0.035 ± 0.004) (0.007 + 0.010 -0.003) (0.015 ± 0.007) (0.063 ± 0.004) (0.018 ± 0.006)
TPSWLC
0805 MM 3.45 0.51 0.76 1.27 1.02 0.46
(in.) (0.136) (0.020) (0.030) (0.050) (0.040) (0.018)
1206 MM 4.54 0.94 1.02 1.65 1.09 0.71
(in.) (0.179) (0.037) (0.040) (0.065) (0.043) (0.028)
TYPICAL FEEDTHRU CHIP CAP CONNECTION
Feedthru Chip Component Model Physical Layout - A
Physical Layout - B
Vcc or
Signal In
Signal In
The terminals are connected internally side to side.
Left side and right side are connected and front and
back are connected internally.
For Decoupling, the chip is usually surrounded by
four vias, two for Vcc and two for GND.
For Signal Filtering, the in and out lines need to be
separated on the circuit board.
Vcc or
Signal Out
Signal Out
Ground
Ground
Ground
Vcc Vcc
Ground
Ground
3
Feedthru 0805/1206 Capacitors
W2F/W3F Series
20
10
0
-10
470pF
100pF
47pF
22pF
220pF
-20
-30
-40
-50
-60110
dB
100
Frequency, MHz
1000 10000
-70
10
0
-10
-20
-30
-40
-50
-60
110
dB
100
Frequency, MHz
1000 10000
1000pF
4700pF
10000pF
2200pF
22000pF
47000pF
1000pf
22,000pf
2200pf
0
-20
-40
-60
dB
10 100 1000
Frequency, MHz
22pf
470pf
100pf
220pf
47pf
0
-20
-40
-60
dB
10 100 1000
Frequency, MHz
PERFORMANCE CHARACTERISTICS
0805 - dB vs. Frequency
NP0
1206 - dB vs. Frequency
NP0 X7R
X7R
4
Feedthru 0805/1206 Capacitors
W2F/W3F Series
PERFORMANCE CHARACTERISTICS
30.00
35.00
40.00
25.00
20.00
0.3 0.5 0.7
Current (A)
Component Temperature (°C)
0.8 1.00 1.20
100pf 220pf
47pf
470pf
30.00
35.00
40.00
25.00
20.00
0.3 0.5 0.7
Current (A)
Component Temperature (°C)
0.8 1.00 1.20
1000pf 2200pf 4700pf
10nf
47nf
22nf
100pf 22pf 47pf 470pf 220pf
40.00
20.00
0.00
0.3 0.5 0.75
Current (A)
0.87 1.00 1.20
Component Temperature (°C)
2200pf
40.00
20.00
0.00
0.3 0.5 0.75
Current (A)
Component Temperature (°C)
0.87 1.00 1.20
22,000pf 1000pf
0805 NP0
Current vs. Temperature
0805 X7R
Current vs. Temperature
1206 NP0
Current vs. Temperature
1206 X7R
Current vs. Temperature
5
High Current Feedthru Capacitors
W2H/W3H Series
HOW TO ORDER
PINOUT CONFIGURATION
GENERAL DESCRIPTION
High current feedthru capacitors are designed as a broad-
band EMI filter that is specially designed to have high current
handling capability. These SMT feedthru filters offer an
optimized frequency response with high attenuation across
a wide RF spectrum due to optimized parallel and series
inductances. These W2H/W3H feedthru filters can actually
replace discrete L/C filter networks.
FEATURES
• Low parallel inductance provides significant noise
reduction in circuits with operating frequencies up to 5GHz
• Broad frequency response with high attenuation
• High rated current – up to 2A for 0805 and up to 5A
for 0612
• Small size – 0805 and 0612 case size
• Reeling in accordance with EIA-481
MECHANICAL CHARACTERISTICS
• Available in EIA 0805 and 0612 cases
• Plated Tin over Nickel Barrier
• Packaged in Tape & Reel
TYPICAL APPLICATIONS
• High current power (Vcc) lines
• PA decoupling
• DC:DC converters
• Regulators
• Power supervisory circuits
W2H1
Size & Style
W2H1=0805
W3H1=0612
5
Voltage
3=25v
5=50v
1=100v
C
Dielectric
A=NP0
C=X7R
473
Capacitance
Code
8
Capacitance
Tolerance
8=+50/-20%
M=±20%
A
Failure
Rate
A=Not
Applicable
T
Terminations
T=Plated Ni
And Sn
1A
Packaging
1A=7" Reel
4000 pcs
3A=13" Reel
4000 pcs
Signal/Vcc Signal/Vcc
Ground
Ground
W2H1 – 0805 Style
Signal/Vcc
Si
g
nal/Vcc
Ground
Ground
W3H1 – 0612 Style
6
High Current Feedthru Capacitors
W2H/W3H Series
ELECTRICAL PARAMETERS
Insulation Resistance 1000 mOhms Minimum
DC Resistance <150 mOhms
Operating Temperature -55C to +125C
CAPACITOR VALUES
Part Number Size Dielectric Capacitance Tolerance Voltage Current
W2H13C 104 8AT 0805 X7R 100,000pF +50%, -20% 25V 2A
W2H15C 473 8AT 0805 X7R 47,000pF +50%, -20% 50V 2A
W2H15C 223 8AT 0805 X7R 22,000pF +50%, -20% 50V 1A
W2H15C 103 8AT 0805 X7R 10,000pF +50%, -20% 50V 1A
W2H15C 102 8AT 0805 X7R 1,000pF +50%, -20% 50V 1A
W2H11A 471 8AT 0805 NP0 470pF +50%, -20% 100V 0.5A
W2H11A 221 8AT 0805 NP0 220pF +50%, -20% 100V 0.5A
W2H11A 101 8AT 0805 NP0 100pF +50%, -20% 100V 0.5A
W2H11A 470 8AT 0805 NP0 47pF +50%, -20% 100V 0.5A
W2H11A 220 8AT 0805 NP0 22pF +50%, -20% 100V 0.5A
W3H13C 104 8AT 0612 X7R 100,000pF +50%, -20% 25V up to 5A
W3H15C 473 8AT 0612 X7R 47,000pF +50%, -20% 50V up to 5A
W3H15C 223 8AT 0612 X7R 22,000pF +50%, -20% 50V up to 4A
W3H15C 103 8AT 0612 X7R 10,000pF +50%, -20% 50V up to 3A
W3H11A 471 8AT 0612 NP0 470pF +50%, -20% 100V up to 4A
W3H11A 221 8AT 0612 NP0 220pF +50%, -20% 100V up to 4A
W3H11A 101 8AT 0612 NP0 100pF +50%, -20% 100V up to 4A
W3H11A 470 8AT 0612 NP0 47pF +50%, -20% 100V up to 3A
W3H11A 220 8AT 0612 NP0 22pF +50%, -20% 100V up to 3A
7
High Current Feedthru Capacitors
W2H/W3H Series
PHYSICAL DIMENSIONS
PAD DIMENSIONS
LWTBW BL ES EW X S
W2H1– 0805 MM 2.01 ± 0.20 1.25 ± 0.20 1.14 Max. 0.46 ± 0.10 0.18 + 0.25 -0.08 NA 0.25 ± 0.13 1.02 ± 0.10 0.23 ± 0.05
(in.) (0.079 ± 0.008) (0.049 ± 0.008) (0.045 Max.) (0.018 ±0.004) (0.007 + 0.010 -0.003) (0.010 ± 0.005) (0.040 ± 0.004) (0.009 ± 0.002)
W3H1– 0612 MM 1.60 ± 0.20 3.20 ± 0.20 1.22 Max. 2.80 ± .127 0.18 + 0.25 -0.08 0.41 ± 0.10 0.41 ± 0.10 1.60 ± 0.10 1.40 ± 0.07
(in.) (0.063 ± 0.008) (0.126 ± 0.008) (0.048 Max.) (0.110 ± 0.005) (0.007 + 0.010 -0.003) (0.016 ± 0.004) (0.016 ± 0.004) (0.063 ± 0.004) (0.055 ± 0.003)
TP SWL CX
W2H1– 0805 MM 3.45 0.51 0.76 1.27 1.02 0.46 NA
(in.) (0.136) (0.020) (0.030) (0.050) (0.040) (0.018)
W3H1– 0612 MM 2.54 3.05 1.12 .460 .610 .330 .710
(in.) (0.100) (0.120) (0.044) (0.018) (0.024) (0.013) (0.028)
EW
W
WS
P
PL
S
BL
BW
T
X
L
T
C
EW
L
S
X
W
C
L
S
BL
BW
T
X
W
ES
P
T
W2H1 – 0805 Style
W3H1 – 0612 Style
PHYSICAL DIMENSIONS AND PAD LAYOUT
8
High Current Feedthru Capacitors
W2H/W3H Series
TYPICAL S21 PEFORMANCE
20
10
0
-10
470pF
100pF
47pF
22pF
220pF
-20
-30
-40
-50
-60110
dB
100
Frequency, MHz
1000 10000
-70
10
0
-10
-20
-30
-40
-50
-60
110
dB
100
Frequency, MHz
1000 10000
1000pF
4700pF
10000pF
2200pF
22000pF
47000pF
0805 NP0
0
-5
-10
-15
-20
-25
-30
-35
-40
-45110
dB
100
Frequency, MHz
1000 10000
47pF
100pF
22pF
220pF
470pF
0612 NP0
0805 X7R
0
-10
-20
-30
-40
-50
-60 110
dB
100
Frequency, MHz
1000 10000
10000pF
47000pF
22000pF
100000pF
0612 X7R
9
Feedthru 0805/1206 Capacitors
W3F4 Series - 4 Element 1206 Feedthru Array
W3 F 4 5 C 223 8 A T 3 A
Style Size Feedthru Number Voltage* Dielectric Capacitance Capacitance Failure Terminations Packaging Code Quantity Code
2=0805 of 1=100v A=NP0 Code Tolerance Rate T=Plated (Reel Size) (Pcs./Reel)
3=1206 Elements 5=50v C=X7R 8=+50/-20% A=Not 1=7" Reel F=1,000
Applicable Embossed Tape A=2,000,
3=13" Reel 4,000 or
Embossed Tape 10,000
*Note: NP0 available in 100V only and X7R available in 50V only.
GENERAL DESCRIPTION
The Feedthru Capacitor Array contains four elements with
a common ground connection. This makes them an ideal
choice for Multi-line designs needing EMI suppression,
broadband I/O filtering or Vcc power line conditioning.
Additional benefits are reduced component count and PCB
space savings. The unique construction provides low par-
allel inductance and offers excellent decoupling capability
for all high di/dt environments. It provides significant noise
reduction in digital circuits to <5 GHz. A number of capac-
itor values are available in NP0 and X7R ceramic dielectrics.
PERFORMANCE CHARACTERISTICS
CAPACITOR VALUES
NP0 X7R
Capacitance Tolerance
+50%, -20% +50%, -20%
Voltage Rating 100V 50V
Current Rating 300mA 300mA
Insulation Resistance 1000MΩ1000MΩ
DC Resistance <0.6Ω<0.6Ω
Operating Temperature Range -55 to +125°C
SIGNAL LINE - INPUT OUTPUT
GROUND
W3F4 Series
1206
Part Number Size Voltage Dielectric Capacitance
W3F41A 220 8ATxx 1206 100V NP0 22pF
W3F41A 470 8ATxx 1206 100V NP0 47pF
W3F41A 101 8ATxx 1206 100V NP0 100pF
W3F45C 221 8ATxx 1206 50V X7R 220pF
W3F45C 471 8ATxx 1206 50V X7R 470pF
HOW TO ORDER
10
Feedthru 0805/1206 Capacitors
W3F4 Series - 4 Element 1206 Feedthru Array
DIMENSIONS
PAD LAYOUT DIMENSIONS
LWTBWBLP X SES
3.25±0.15 1.60±0.20 1.22 max 0.41±0.10 0.18 0.76 ref. 1.14±0.10 0.38±0.10 0.41±0.10
(0.128±0.006) (0.063±0.008) (0.048 max) (0.016±0.004) (0.007 (0.030 ref.) (0.045±0.004) (0.015±0.004) (0.016±0.004)
AB C D E F
mm 0.6 1.6 2.2 0.35 0.76 2.6
Inches (0.024) (0.064) (0.088) (0.014) (0.030) (0.104)
L
ES
BW
W
P
S
Center Line
X
BL
W
= Feedthru Paths
= Common Ground
F
D
D
E
A
A
B
C
+0.25
-0.08
+0.010
-0.003
)
millimeters (inches)
11
22pF
100pF
47pF
0
-10
-20
-30
-40
dB
0.01 0.1 1.0 10
Frequency, GHz
Feedthru 0805/1206 Capacitors
W3F4 Series - 4 Element 1206 Feedthru Array
220pF
470pF
0
-20
-10
-30
-40
-50
dB
0.01 0.1 1.0 10
Frequency, GHz
S21 vs. Frequency
NP0 4 Element Feedthru
S21 vs. Frequency
X7R 4 Element Feedthru
PERFORMANCE CHARACTERISTICS
12
Feedthru 0805/1206 Capacitors
W2F/W3F/W3F4 Series
APPLICATIONS
EMI Suppression
Broadband I/O Filtering
Vcc Line Conditioning
FEATURES
Standard EIA Sizes
Broad Frequency Response
Low ESR
8 mm Tape and Reel
MARKET SEGMENTS
Computers
Automotive
Power Supplies
Multimedia Add-On Cards
Bar Code Scanners and Remote Terminals
PCMCIA Cards
Medical Instrumentation
Test Equipment
Transceivers/Cell Phones
Applications
Typical Circuits Requiring
EMI Filtering
THE FOLLOWING APPLICATIONS AND SCHEMATIC DIAGRAMS SHOW WHERE
FEEDTHRU CAPACITORS MIGHT BE USED FOR EMI SUPPRESSION
• Digital to RF Interface Filtering
• Voltage Conditioning in RF Amplifiers
• Power Decoupling GaAs FET Transistor Preamplifier
• Vcc Line Filtering on Frequency Control Circuit
• Clock, Data, Control Line High Frequency Decoupling (Frequency Synthesizer)
(SEE APPLICATION NOTES)
Audio
Digital
Block
RF
Block
= Feedthru
DIGITAL TO RF INTERFACE FILTERING
13
S.M. = SILVER MICA
RFC1
FB
L3
Q1
GD
S
L4
L5
R2
R1
R3
L6
1N914
D1
D2
L1 L2
J2
OUTPUT
J1
INPUT
C2
C3
C5
OUT IN
GND
U1
78L05
C4
C1 C8
C6
0.1 C7
0.1
1.5pF
TYPICAL
5.6
S.M.
62
1/4W
51
1/8W
16V
0.4W
1000
F. T.
15
S.M.
200
CHIP
500
POT
200
CHIP
200
CHIP
+12/14V
14mA
= Feedthru
OUT
C85
C87
2
0.022
C82
82 D25
1N914
2N5486
Q25
R136
1M
R141
100
R140
100
R139
100k
R138
100k
R137
47k
C84
50
C91
0.022
C89
0.022
C86
10
C88
0.022
C90
T14
C81
24pF
C80
82
L3
C83
24
VCC
IN
GND
To Bilateral
Mixer
U10
Reg
78L05
6-6.35 MHz VFO
FB1
Q26 40673
+
2.2µF
16V
= Feedthru
Feedthru 0805/1206 Capacitors
W2F/W3F Series
= Feedthru
Q1
Z1
Z3
Z2
Z4
Z5
+28V
+28V
RFC7
RFC8
RFC1
RFC5
RFC6
R6
D1
C9
C1
C5
C2 C3
C7 C8 C15
C26 C20
C14
C21
C22
C23
C24
C16C6
C4 C11 C12
C25 C18
C13
C10
R1
T1
RF in
RF Out
T2
R4
R2
R3
R5
L1
Filter
L2
L3
RFC2
RFC4
RFC3
+28V
Z7
Z6
Z8
Q2
Q4
Q3
VOLTAGE CONDITIONING IN RF AMPLIFIERS
POWER DECOUPLING GaAs FET TRANSISTOR PREAMPLIFIER
Vcc LINE FILTERING ON FREQUENCY CONTROL CIRCUIT
14
High Current Feedthru Capacitors
W2H/W3H Series
APPLICATIONS
W3H15C2238AT1A
VC121018J390 M
CONTROL
TransGuard
Vcc Filtering Dual Power Switch Filtering
PCMCI
Card
I/O Bus
Controller
3.3V 3VIN
5VIN
5V
W2H15C1048AT1A W2H15C1038AT1A
VC120630D650
RF OUT
TransGuard
PA Filtering Regulator Filtering
OU
T
IN
W3H15C4738AT1A
15
Feedthru 0805/1206 Capacitors
W2F/W3F/W3F4 Series
EMI REDUCTION THROUGH THE USE OF SMT FEEDTHRU CAPACITORS
ABSTRACT
Today’s high speed, miniaturized semiconductors have
made EMI issues a key design consideration. This paper
briefly defines EMI and illustrates the capability of SMT
feedthru capacitors.
WHAT IS EMI?
The term EMI stands for Electromagnetic Interference and
refers to signals/energy interfering with a circuit or systems
functions.
In an electronic system, two classes of energy are generated
- wanted and unwanted. Both are potential sources of EMI(1).
Wanted signals such as clocks and bus lines could cause
EMI if they were not decoupled, terminated or filtered prop-
erly. Unwanted signals (cell phones, police radios, power
supply noise, etc.) could be conducted or radiated into the
circuit due to poor circuit layout, improper decoupling or a
lack of high frequency filtering.
In either type of EMI signal interference, the system could be
rendered useless or put into a state which would cause early
failure of its semiconductors. Even worse, the unwanted
energy could cause an incorrect answer to be generated
from a computer by randomly powering a gate up or down.
From all of this we can gather that EMI is a complex prob-
lem, usually with no one solution. EMI interference can be a
random single shot noise (like a SCR firing) or repetitive in
nature (stepper motor or relay noise). The interference can
enter into our designs either by being induced by E/B fields,
or it can be conducted through control lines or a communi-
cation bus. EMI can even be self generated by internal com-
ponents that generate steep risetime waveforms of voltage
or current.
HOW CAN EMI BE CONTROLLED?
EMI is most efficiently controlled by realizing it to be a design
parameter in the earliest stages of the design. This way, the
board layout can be optimized with large power and ground
planes which will be low impedance in nature. The use of
SMT feedthru filters will yield optimal results.
SMT FEEDTHRU CAPACITORS
AVXintroduced feedthru capacitors to supply a broadband
EMI filter capacitor for source suppression and receiver noise
reduction.
SMT feedthru capacitors use the same material systems as
standard ceramic capacitors. They exhibit the same reliabili-
ty and can be processed in the same end user production
methods as standard capacitors. What feedthru capacitors
offer is an optimized frequency response across a wide RF
spectrum due to a modified internal electrode design.
An application comparison between an SMT feedthru and a
discrete capacitor is shown in Figure 1.
The key difference between the two filtering methods is that
the feedthru has a much lower inductance between the sig-
nal line and ground than the capacitor. The difference in
inductances can be in the range of roughly one order mag-
nitude with a feedthru capacitor. This inductance can be
shown in an electrical sense through the model for a feedthru
and a capacitor (Figure 2).
The feedthru capacitor has a minimized parallel inductance
and an optimal series inductance (which broadens the
frequency response curve). Typical attenuation graphs are
shown in Figure 3A.
These curves demonstrate feedthru capacitors advantage of
a broad frequency response with high attenuation. They also
serve as a comparison to the inductance of even lower
inductance devices (primarily used in extreme decoupling
cases and switch mode power supplies) - see Figure 3B.
(1)Practical Design for Electromagnetic Compatibility edited by Rocco F. Ficchi
Hayden Book Company 1978
INPUT
FEEDTHRU FILTER
OUTPUT
Signal Trace Signal Trace
INPUT
SMT CAPACITOR
OUTPUT
Signal Trace Signal Trace
Figure 1. Comparison of Feedthru Capacitors
to Discrete Capacitors
Figure 2. Comparison of Feedthru Capacitors
to Discrete Capacitors
FEEDTHRU FILTER
OUTPUT
INPUT OUTPUT
INPUT
SMT CAPACITOR
16
Feedthru 0805/1206 Capacitors
W2F/W3F/W3F4 Series
SMT FEEDTHRU CAPACITOR
TERMINOLOGY
AVX’s feedthru capacitors have additional technical termi-
nologies relative to standard ceramic capacitors. The reason
for this is due to the series manner in which the feedthru
element is connected to the circuit.
The most important term is DC Resistance. The DC resis-
tance of the feedthru is specified since it causes a minor sig-
nal attenuation which designers can calculate by knowing
the maximum resistance of the part.
The maximum current capability of the part is also of interest
to designers since the feedthru may be placed in series with
the voltage line.
APPLICATION AND SELECTION OF
SMT FEEDTHRU CAPACITOR FILTERS
EMI suppression and receiver noise reduction can be
achieved most effectively with efficient filtering methods.
Attenuations of over 100 dB are achievable depending on
the complexity and size of the filters involved.
However, before filtering is discussed, another EMI reduction
method is noise limiting, using a series element (inductors or
resistors). This method is easy to implement and inexpen-
sive. The problem it poses is that it can only reduce noise by
-3 to -10 dB. Because of that, series element EMI reduction
is primarily used where there is a poor ground.
SMT feedthru filter capacitors can actually replace discrete
L/C filter networks (depending on the frequency response
needed). The SMT filter capacitors should first be chosen for
its specific frequency response. Then the voltage rating,
DCR, and current capability must be evaluated for circuit
suitability. If there is not a match on voltage, current and DC
resistance ratings, the designer must select the closest avail-
able frequency response available on parts that will meet the
design’s power spec.
The top 5 applications for SMT feedthru filter capacitors are:
20
10
0
-10
470pF
100pF
47pF
22pF
220pF
-20
-30
-40
-50
-60110
dB
100
Frequency, MHz
1000 10000
1000pf
22,000pf
2200pf
0
-20
-40
-60
dB
10 100 1000
Frequency, MHz
Figure 3A. Feedthru Capacitor Attenuation Graphs
(Forward Transmission Characteristic - S21)
1206
0612
Feedthru
IDC
0.03
0.1
0.3
1
3
10
30
Impedance
Frequency, MHz
10001001010.10.01
Figure 3B. Comparison of SMT Capacitor
Frequency Response to Feedthru Filters
0805 - dB vs. Frequency
NP0
1206 - dB vs. Frequency
X7R
1. Digital to RF interface filtering.
2. Control line high frequency decoupling.
3. Data and clock high frequency decoupling.
4. Power line high frequency decoupling.
5. High gain and RF amplifier filtering.
Feedthru 0805/1206 Capacitors
W2F/W3F/W3F4 Series
A typical example of data, clock control line and power line
filtering is shown below:
Clock, Data, Control Line High Frequency Decoupling
(Frequency Synthesizer)
= Feedthru
CLOCK
DATA
ENABLE
REFERENCE
INPUT
Vcc
+5V
LOCK
DETECTOR
1T1091615
10K
10K
10K
51 1000pF 1000pF
1000pF* 1000pF*
10K*
22K*
Cbypass
Cout
VLine
VCC
VCC
FOR OP AMP
VCC
FOR VCO
RF
OUTPUT
Cbypass
10K*
18 18
18
51
100pF* 100pF*
100pF*
100pF
1000pF
LMX2314
VCOIC2
IC1
12345678
2
3
4
7
-
+
6
CONCLUSION
EMI problems will continue to play a large role in designers
priorities. AVX SMT feedthru filters are an easy way to
achieve broad band EMI reduction in a small SMT package.
SMT feddthru filters can help reduce cost designs by elimi-
nating some types of L/C filters, increasing system reliability
and saving valuable PCB area. SMT feedthru filters are
offered in both 0805, 1206 single element packages or in
1206 four element packages.
NOTICE: Specifications are subject to change without notice. Contact your nearest AVX Sales Office for the latest specifications. All statements, information and
data given herein are believed to be accurate and reliable, but are presented without guarantee, warranty, or responsibility of any kind, expressed or implied.
Statements or suggestions concerning possible use of our products are made without representation or warranty that any such use is free of patent infringement and
are not recommendations to infringe any patent. The user should not assume that all safety measures are indicated or that other measures may not be required.
Specifications are typical and may not apply to all applications.
S-FTCA00M703-C
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