Circuit designers today are challenged with maintaining Signal and Power Integrity amid increasing Electro-Magnetic Compliance (EMC) requirements,
while at the same time lowering system costs. X2Y
®
Technology is an enabler to this end, providing a quantum leap in circuit performance. X2Y
®
replaces multiple standard passives and Integrated Passive Components with a single device, freeing precious board space for additional active
components or design miniaturization. In short, X2Y
®
gives end-users the cost advantage they need to compete in today’s market.
X2Y
®
Technology Overview
X2Y
®
components share many common traits with conventional multi-layer ceramic capacitors (MLCC) to facilitate adoption by end-users into their
manufacturing processes
• Same component sizes (0603, 0805, 1206, etc.)
• Same pick and place equipment
• Same voltage ratings
• Same dielectric, electrode and termination materials
• Same industry test standards for component reliability
The X2Y
®
design - A Capacitive Circuit
A standard bypass capacitor has opposing electrode layers stacked inside. An X2Y
®
adds another set of electrode layers to effectively surround each
existing electrode within the stack 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.
A
G1
G2
B
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
(Pwr 1)
G1
Return
(Pwr 2)
B
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.
A
G2
Signal
(Power)
G1
Return
(Ground)
A
G2
B
2
www.johanson dielectrics.com
EMI Filtering with X2Y
®
Many 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. This effectively eliminates the need for a common mode choke*. 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
DC Motor EMI Reduction: A Superior Solution
One X2Y
®
component has successfully replaced 7 discrete filter
components while achieving superior EMI filtering.
X2Y
®
2.0 x 1.3 x 1.0 mm
Signal Line Filter for USB & RJ45
One X2Y
®
component can effectively filter high speed signal lines
replacing replacing multiple inductive and ferrite components.
