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
• Effect of voltage variation eliminated
• Matched line-to-ground capacitance
• Effects of aging & temperature are equal on both caps
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
X2Y®
10nF
Discrete
10nF, 2 @ 220 pF
Comments
DC offset shift
< 0.1 µV
91 dB
< 0.1 µV
92 dB
Referred to input
Common mode rejection
Source: Analog Devices, “A Designer’s Guide to Instrumentation Amplifiers (2nd Edition)” by Charles Kitchin and Lew Counts
Common Mode Choke Replacement
DC Motor EMI Reduction: A Superior Solution
One X2Y component has successfully replaced 7 discrete filter
®
In this example, a 5 µH common mode choke is replaced by an
®
0805, 1000pF X2Y component acheiving superior EMI filtering by a
components while achieving superior EMI filtering.
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
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.
Signal lines filtered with X2Y®
Signal lines filtered with LC Filter Chip
Other X2Y® Filter Applications
DC-DC converters, power I/O, connectors (RJ45, D-sub), audio/voice/data, CAN, high-speed differential.
Effectively replaces common mode chokes, inductors, ferrites and feedthru capacitors.
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JOHANSON [ JOHANSON TECHNOLOGY INC. ]
