X2Y
®
F
ilter
& D
ecoupling
c
apacitors
The X2Y
®
Design - A Capacitive Circuit
X2Y components share many common features with standard multi-layer ceramic capacitors (MLCC) for easy adoption by end-users.
• Same component sizes (0603, 0805, 1206, etc.)
• Same pick and place equipment
• Same dielectric, electrode and termination materials
• Same industry test standards for component reliability
®
A standard multi-layer ceramic capacitor (MLCC) consists of opposing electrode layers A & B. The X2Y
®
design adds another set of electrode layers (G) which
effectively surround each existing electrode of a two-terminal capacitor. The only external difference is two additional side terminations, creating a four-terminal
capacitive circuit, which allows circuit designers a multitude of attachment options.
G1
B
A
G2
X2Y
®
Circuit 1: Filtering
When used in circuit 1 configuration the X2Y
®
filter capacitor is connected across two signal lines. Differential mode noise is filtered to ground by the two Y
capacitors, A & B. Common mode noise is cancelled within the device.
Signal 1
Ground
Signal 2
G1
A
G2
B
Experts agree that balance is the key to a “quiet” circuit. X2Y® is a balanced circuit device with two equal
halves, tightly matched in both phase and magnitude with respect to ground. Several advantages are
gained by two balanced capacitors sharing a single ceramic component body.
• Exceptional common mode rejection
• Effects of aging & temperature are equal on both caps
• Effect of voltage variation eliminated
• Matched line-to-ground capacitance
InAmp Input Filter Example
In this example, a single Johanson X2Y
®
component was used to filter noise at the input of a DC
instrumentation amplifier. This reduced component count by 3-to-1 and costs by over 70% vs.
conventional filter components that included 1% film Y-capacitors.
Parameter
DC offset shift
Common mode rejection
X2Y
®
10nF
< 0.1 µV
91 dB
Discrete
10nF, 2 @ 220 pF
< 0.1 µV
92 dB
Comments
Referred to input
Source: Analog Devices, “A Designer’s Guide to Instrumentation Amplifiers (2nd Edition)” by Charles Kitchin and Lew Counts
Common Mode Choke Replacement
In this example, a 5 µH common mode choke is replaced by an 0805, 1000pF
X2Y
®
component acheiving superior EMI filtering by a component a fraction
of the size and cost.
No Filter
CMC 5uH
X2Y® 1000pF
Ambient
Common Mode Choke
9.0 x 6.0 x 5.0 mm
2.0 x 1.3 x 1.0 mm
DC Motor EMI Reduction: A Superior Solution
One X2Y
®
component has successfully replaced 7 discrete filter components
while achieving superior EMI filtering.
X2Y
®
2
www.johanson dielectrics.com
X2Y
®
F
ilter
& D
ecoupling
c
apacitors
X2Y
®
Circuit 2: Decoupling
When used in circuit 2 configuration, A & B capacitors are placed in parallel effectively doubling the apparent capacitance while maintaining an ultra-low
inductance. The low inductance advantages of the X2Y® Capacitor Circuit enables high-performance bypass networks at reduced system cost.
Power
G1
A
G2
B
• Low ESL (device only and mounted)
• Broadband performance
• Effective on PCB or package
• Lower via count, improves routing
• Reduces component count
• Lowers placement cost
Ground
Component Performance
The X2Y
®
has short, multiple and opposing current paths
resulting in lower device inductance.
Mounted Performance
Mutual coupling from
opposing polarity vias
lowers inductance when
mounted on a PCB.
SYSTEM PERFORMANCE
1:5 MLCC Replacement Example
X2Y’s
®
proven technology enables end-users to use one X2Y
capacitor to replace five conventional MLCCs in a typical high
performance IC bypass design. Vias are nearly cut in half, board
space is reduced and savings are in dollars per PCB.
104 MLCs
0402 47nF
20 X2Y
®
0603 100nF
Transfer Impedance
seen by FPGA
www.johanson dielectrics.com
3
X2Y
®
F
ilter
& D
ecoupling
c
apacitors
X2Y
®
filter capacitors employ a unique, patented low inductance design featuring two balanced
capacitors that are immune to temperature, voltage and aging performance differences.
These components offer superior decoupling and EMI filtering performance, virtually eliminate
parasitics, and can replace multiple capacitors and inductors saving board space and reducing
assembly costs.
A
dvAntAges
•
•
•
•
•
One device for EMI suppression or decoupling
Replace up to 7 components with one X2Y
Differential and common mode attenuation
Matched capacitance line to ground, both lines
Low inductance due to cancellation effect
A
pplicAtions
•
•
•
•
•
FPGA / ASIC / µ-P Decoupling
DDR Memory Decoupling
Amplifier FIlter & Decoupling
High Speed Data Filtering
Cellular Handsets
CB
Equivalent Circuits
A
G1
B
G2
Cross-sectional View
G
A
Dimensional View
CB
EB
W
B
G
W
L
T
EB
T
<10pF
10pF
22pF
27pF
33pF
47pF
100pF
220pF
470pF
1000pF
1500pF
2200pF
4700pF
.010µF
.022µF
.047µF
0.10µF
0.18µF
0.22µF
0.33µF
0.40µF
Circuit 1
(Y Cap.)
Circuit 2
(2*Y Cap.)
L
<20pF
20pF
44pF
54pF
66pF
94pF
200pF
440pF
940pF
2000pF
3000pF
4400pF
9400pF
0.47µF
474
16
1*
0.94µF
.020µF
.044µF
.094µF
0.20µF
0.36µF
0.44µF
0.68µF
SIZE
0402
CAP.
CODE
NPO
X7R
NPO
X7R
NPO
X7R
NPO
X7R
X7R
X7R
X7R
XRX
100
220
270
330
470
101
221
471
102
152
222
472
103
223
473
104
184
224
334
404
0.80µF
50
50
50
50
50
50
50
50
50
50
50
50
50
50
16
0603
1*
1*
1*
1*
1*
50
1*
50
1*
1*
50
1*
1*
1*
1*
1*
50
1*
1*
1*
1*
1*
50
50
25
16
1*
1*
1*
50
25
16
10
6
0805
1*
1*
1*
1*
1*
1206
1210
1410
1812
VOLTAGE
RATINGS
6 = 6.3 VDC
10 = 10 VDC
16 = 16 VDC
25 = 25 VDC
50 = 50 VDC
1* = 100 VDC
1*
1*
1*
1*
1*
1*
50
1*
25
50
1*
1*
1*
Circuit 1 Capacitance (Balanced Filtering) = A (or B) to G Circuit 2 Capacitance (Decoupling) = A + B to G
Rated voltage is for A or B to ground. Contact factory for part combinations not shown.
X2Y® technology patents and registered trademark under license from X2Y ATTENUATORS, LLC
4
www.johanson dielectrics.com
105
16
2.0µF
1.0µF
PCB设计
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