EMI® 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.

Automotive version (AEC-Q200) available on request.

X2Y Filter and Decoupling Capacitors
General Information
  • Amplifier FIlter & Decoupling
  • High Speed Data Filtering
  • EMC I/O Filtering
  • FPGA / ASIC / μ-P Decoupling
  • DDR Memory Decoupling
  • 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
Key Features:
  • AEC-Q200 Automotive Qualification (as required)
Common Traits with Conventional MLCC:
  • 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
X2Y Filter and an MLC Capacitor
X2Y® components share many common traits with conventional multi-layer ceramic capacitors (MLCC) to facilitate adoption by end-users into their manufacturing processes.
The X2Y® Design - A Balanced, Low ESL, "Capacitor Circuit"

The X2Y® capacitor design starts with standard 2 terminal MLC capacitor’s opposing electrode sets, A & B, and adds a third electrode set (G) which surround each A & B electrode. The result is a highly vesatile three node capacitive circuit containing two tightly matched, low inductance capacitors in a compact, four-terminal SMT chip.

X2Y capacitor design starts with standard 2 terminal MLC capacitor’s opposing electrode sets

X2Y Filtering schematic

EMI Filtering:
The X2Y® component contains two shunt or “line-to-ground” Y capacitors. Ultra-low ESL (equivalent series inductance) and tightly matched inductance of these capacitors provides unequaled high frequency Common-Mode noise filtering with low noise mode conversion. X2Y® components reduce EMI emissions far better than unbalanced discrete shunt capacitors or series inductive filters. Differential signal loss is determined by the cut off frequency of the single line-to-ground (Y) capacitor value of an X2Y®.

X2Y decoupling schematic

Power Bypass / Decoupling
For Power Bypass applications, X2Ys® two “Y” capacitors are connected in parallel. This doubles the total capacitance and reduces their mounted inductance by 80% or 1/5th the mounted inductance of similar sized MLC capacitors enabling high-performance bypass networks with far fewer components and vias. Low ESL delivers improved High Frequency performance into the GHz range.

GSM RFI Attenuation in Audio & Analog

GSM handsets transmit in the 850 and 1850 MHz bands using a TDMA pulse rate of 217Hz. These signals cause the GSM buzz heard in a wide range of audio products from headphones to concert hall PA systems or “silent” signal errors created in medical, industrial process control, and security applications. Testing was conducted where an 840MHz GSM handset signal was delivered to the inputs of three different amplifier test circuit configurations shown below whose outputs were measured on a HF spectrum analyzer.

  • No input filter, 2 discrete MLC 100nF power bypass caps.
  • 2 discrete MLC 1nF input filter, 2 discrete MLC 100nF power bypass caps.
  • A single X2Y 1nF input filter, a single X2Y 100nF power bypass cap.

X2Y configuration provided a nearly flat response above the ambient and up to 10 dB imrpoved rejection than the conventional MLCC configuration.

X2Y GSM RFI Attenuation in Audio and Analog frequency chart
Capacitance Values X2Y Capacitance selection chart
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.

X2Y EMI Filtering Circuit diagram

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
Amplifier 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.

ParameterX2Y® 10nFDiscrete 10nF, 2@220 pFComments
DC offset shift< 0.1 µV< 0.1 µVReferred to input
Common mode rejection91 dB92 dB 

Source: Analog Devices, “A Designer’s Guide to Instrumentation Amplifiers (2nd Edition)” by Charles Kitchin and Lew Counts

X2Y Amplifier Input Filter diagram
Common Mode Choke Replacement
  • Superior High Frequency Emissions Reduction
  • Smaller Sizes, Lighter Weight
  • No Current Limitation
  • Vibration Resistant
  • No Saturation Concerns
x2y common mode choke replacement
X2Y Measured Common Mode Rejection
DC Motor EMI Reduction: A Superior Solution

One X2Y® component has successfully replaced 7 discrete filter components while achieving superior EMI filtering.

DC Motor EMI Reduction graph Parallel Capacitor Solution

A common design practice is to parallel decade capacitance values to extend the high frequency performance of the filter network. This causes an unintended and often over-looked effect of anti-resonant peaks in the filter networks combined impedance. X2Y’s very low mounted inductance allows designers to use a single, higher value part and completely avoid the anti-resonance problem. The impedance graph on right shows the combined mounted impedance of a 1nF, 10nF & 100nF 0402 MLC in parrallel in RED. The MLC networks anti-resonance peaks are nearly 10 times the desired impedance. A 100nF and 47nF X2Y are plotted in BLUE and GREEN. (The total capacitance of X2Y (Circuit 2) is twice the value, or 200nF and 98nF in this example.) The sigle X2Y is clearly superior to the three paralleled MLCs.

Decade MLCs versus X2Y Impedance
Signal Line Filter for USB & RJ45

One X2Y® component can effectively filter high speed signal lines replacing replacing multiple inductive and ferrite components.

Signal Line Filter for USB and RJ45 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.

Electrical Specifications
X2Y Electrical Characteristics chart
Mechanical Specifications
Equivalent Circuits
X2Y Mechanical Drawing diagramX2Y Mechanical Drawing chip view
Cross Sectional View
X2Y Cross Section Mechanical Drawing
Dimensional View
X2Y Mechanical Schematic

X2Y Mechanical characteristics graph
Optimizing X2Y Performance with Proper Attachment Techniques Optimizing X2Y Performance with Proper Attachment Techniques

Use of solder mask beneath component is NOT recommended because of flux/contaminant entrapment.

Optimizing X2Y Performance on the PCB

X2Y capacitors deliver excellent performance in EMI/RFI filtering and Power Bypass applications. Physical and electrical placement on the PCB is critical in achieving good results. A low inductance, dual ground connection is mandatory.

For EMI Filter applications, low inductance PCB routing examples are shown in figures 1 and 2. Figures 3-5 show unbalanced and high inductance connections and should be avoided. For more information  see X2Y EMI Filter Evaluation and PCB Design Guidelines.

EMI Filter Applications: stray inductance must be minimized between signals and the A and B capacitor pads.G1 and G2 connections should be low inductance connections as well. Use star or daisy chain routes, rather than "T" to capacitor pads as show in Figure 1. Read: NEW - X2Y EMI Filter Evaluation & Design Guide for comprehensive information.

figure 1 star layout
Figure 1
figure 2 daisy chain layout
Figure 2
figure 3 T layout
Figure 3
figure 4 Single ground via
Figure 4
figure 5 High ESL GND Traces
Figure 5
PDN Bypass applications

For PDN / Bypass applications the figures on the right compare the X2Y recommended layout against a poor layout. Because of its long extents from device terminals to vias, and the wide via separation, the poor layout exhibits approximately 200% L1 inductance, and 150% L2 inductance compared to recommended X2Y layouts. For more information see X2Y Power Bypass Mounting.

recommended X2Y Bypass Layout
Lab Soldering Precautions

Ceramic capacitors (X2Y® and standard MLC types) can be easily damaged when hand soldered. Thermal cracking of the ceramic body is often invisible even under a microscope.  Factors that increase thermal cracking risk:

  1. 4 terminals to solder can increase hand-soldering time and temperature exposure
  2. Pb-free solders have higher reflow temperatures
  3. Low inductance connections to ground are inherently good heat-sinks

A damaged component may exhibit a short circuit immediately and not recover, or may operate with intermittent Insulation Resistance (IR) levels. If you are not achieving expected results and have followed the other guidelines carefully, check to see you are adhering to the soldering guidelines below:

  • Always pre-heat the PCB and component to within 50°C of solder reflow temperature at 2°C/sec. maximum.
  • Use contact-less hand solder tools such as a hot air pencil, IR lamp, etc.
  • Avoid over-heating of the ceramic component, temperature limit: 260°C for 20-30 seconds max.
  • Use a soldering iron as last resort; 20W max. tip, NO CONTACT with ceramic, limit solder time to 5 seconds max.

A reliable, cost effective prototype PCB reflow soldering process is possible using a household toaster oven. There are several good procedures available on-line by googling "Toaster Oven Soldering"

X2Y® Circuit 2: Decoupling

When used in circuit 2 configuration, A & B capacitors are placed in parallel effectively doubling the effective 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.

X2Y Circuit Decoupling diagram
  • Lower via count, improves routing
  • Reduces component count
  • Lowers placement cost
  • Low ESL (device only and mounted)
  • Broadband Performance
  • Effective on PCB or package
X2Y High Performance Power Bypass - Improve Performance, Reduce Space & Vias

Actual measured performance of two high performance SerDes FPGA designs demonstrate how a 13 component X2Y bypass network significantly out performs a 38 component MLC network.

X2Y High Performance Power Bypass using 38 MLC X2Y High Performance Power Bypass using 13 X2Y
Component Performance
X2Y Component performance X2Y MLC Component Performance graph

The X2Y® has short, multiple and opposing current paths resulting in lower device inductance

PCB Mounted Performance
PCB Mounted Performance coupling X2Y Impedance vs Frequency comparison
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.

System performance graph


Noise improvement 1:3 MLCC Replacement graph
How to Order
X2Y Capacitor Part Number Breakdown

* - Qualification required for automotive application. Not Available for all series - Call factory for info.