
"Absorbs and eliminates GHzBand Multipath Reflection waves and noise
emissions"
Differential Signal Balancer/Commonmode Noise Absorber
CDLDType RSuffix
Multipath Reflection Remover
CDLDType ESuffix
Features
・New, Nonmagnetic CommonMode filter utilizing delay line operating at 4G～28Gbps.
・Restoring Eye Patterns closed due to multipath reflection using the Passive internal CTLE (Continuous Time Linear Equalizer) version. (Please See Technical Note 1)
・Prior Removal and elimination of commonmode noise prevents noise transmission. (Please See Technical Note 2)
・Differential signal interphase skew and uneven Rise/Fall are automatically adjusted, correcting balance. (Please See Technical Note 3)
[Application Examples]
・Semiconductor test device (Gbps) with commonmode noise transmission problems. (Please See Technical Note 4)
・Optical transmission system with an electrical/optical conversion board and highspeed networking device for EMI measure, eye pattern improvement.


This product is a 0805 size multilayered ceramic chiptype LTCC part and is RoHScompliant. Sparameter files (Touchstone format) and SPICE models can be provided for each component.
Care and Handling of LTCC Products

10Gbps Multipath Reflection Removal Example
(Please See Technical Note 1)


12.5Gbps Unbalanced
Stray LC 
28Gbps Unbalanced
Stray LC 
Thru



Thru with
Decision Feedback Equalizer
(DFE) 


6dB Attenuator with
DFE 


CDLD06E (Left)
CDLD03E (Right) 




Common Specifications （provisional）
Input/Output Impedance: 
Differential 100Ω±10%* 
Interval Skew AutoAdjust Time: 
1/4Pw (Pw Spec: 1Unit Interval pulse width <200ps) 
Waveform Distortion: 
Overshoot/Preshoot under ±20% 
Insulation Resistance: 
DC50V, over 100MΩ 
Durable Voltage: 
DC50V, 1 minute 
Rated Current: 
100mA 
Rated Voltage: 
5V 
Operating Temperature Range: 
－40°C to +85°C 
Storage Temperature Range: 
－40°C to +120°C 
* Singleended operation will not produce usable waveforms.


Multipath Reflection Remover
Part Number 
Transmission
Speed(1)* 
Insertion Loss
(2)* 
DC Insertion
Loss
(2)* 
Output Rise
Time
(20%80%) 
Delay Time 
CDLD03E(3)*

25G～28Gbps 
2dB Typ.
(at 13GHz) 
5.5dB Typ. 
25ps Typ. 
30ps Typ. 
CDLD04E(4)*

16Gbps 
2.5dB Typ. (at 8GHz) 
6.0dB Typ. 
30ps Typ. 
40ps Typ. 
CDLD06E(3)*

10G～12.5Gbps 
3dB Typ. (at 6GHz) 
6.0dB Typ. 
35ps Typ. 
60ps Typ. 

Differential Signal Balancer/Commonmode Noise Absorber
Part Number 
Transmission
Speed(1)* 
3dB Passband
(2)* 
Output Rise
Time
(20%80%) 
Delay Time 
DC
Resistance 
CDLD07R(3)*

16G～28Gbps 
DC～20GHz Typ. 
25ps Typ. 
70ps Typ. 
1.0ΩMax. 
CDLD10R

8G～16Gbps 
DC～15GHz Typ. 
30ps Typ. 
100ps Typ. 
1.5ΩMax. 
CDLD15R 
5G～12.5Gbps 
DC～12GHz Typ. 
35ps Typ. 
150ps Typ. 
1.5ΩMax. 
CDLD30R 
4G～8Gbps 
DC～7.5GHz Typ. 
45ps Typ. 
300ps Typ. 
2.5ΩMax. 
(1)* When using the recommended Land Pattern.The case where the passing waveform of 1 unit interval becomes sine wavelike is included. (Please See Technical Note 7)
(2)* When using the recommended Land Pattern.
(3)* Samples available.
(4)* Under development.

［Jumper Features］
After attaching the pads to the printed circuit board, assuming the possibility that this component might not load properly, we have prepared the CDLD00R jumper between the pads.
The CDLD00R is utilized for a minimal time between the input and output terminals and has no effect on the reduction of common mode noise or differential signal balance.
Part Number 
3dB Passband(5)* 
Output Rise Time
(20%80%) 
Delay Time 
DC Resistance 
CDLD00R

DC～20GHz Min. 
25ps Typ. 
10ps Typ. 
1.0ΩMax. 
(5)* When using the recommended Land Pattern. 
Unit:mm(inch) Tolerance:±0.2(±0.008) 

CDLD00R
・No Direction mark
・No connection between 2pin and 5pin


Unit:mm(inch)
Tolerance:±0.1(±0.004) 



1. Specific Land Pattern 


Example for Dielectric Layer 



Characteristics Examples
Pulse response waveform
Transient analysis based on actual Sparameter measurements
(Actual data only extends to 20GHz. Due to lack of bandwidth, Sparameter was used for the
electromagnetic field analysis at 28Gbps and 16Gbps.)
Skew of Input PseudoRandom Bit Sequence: 0ps 
CDLD07R 


28Gbps


16Gbps




[Xaxis: 10ps/div, Yaxis: 200mV/div] 

[Xaxis: 20ps/div, Yaxis: 200mV/div] 



CDLD10R 


16Gbps


10Gbps




[Xaxis: 20ps/div, Yaxis: 200mV/div] 

[Xaxis: 20ps/div, Yaxis: 200mV/div] 



CDLD15R 


10Gbps


5Gbps




[Xaxis: 20ps/div, Yaxis: 200mV/div] 

[Xaxis: 50ps/div, Yaxis: 200mV/div] 



CDLD30R 


8Gbps


5Gbps




[Xaxis: 50ps/div, Yaxis: 200mV/div] 

[Xaxis: 50ps/div, Yaxis: 200mV/div] 



Frequency Characteristics 
CDLD03E (Actual Measurement) 
Sdd21 Differential Transmission


Differential Group Delay




Scc21 Commonmode Transmission


Commonmode power ratio







CDLD04E (Electromagnetic Field Analysis) 
Sdd21 Differential Transmission


Differential Group Delay




Scc21 Commonmode Transmission


Commonmode power ratio







CDLD06E (Actual Measurement ) 
Sdd21 Differential Transmission


Differential Group Delay




Scc21 Commonmode Transmission


Commonmode power ratio







CDLD07R (Actual Measurement) 
Sdd21 Differential Transmission


Differential Group Delay




Scc21 Commonmode Transmission


Commonmode power ratio







CDLD10R (Actual Measurement) 
Sdd21 Differential Transmission


Differential Group Delay




Scc21 Commonmode Transmission


Commonmode power ratio







CDLD15R (Actual Measurement) 
Sdd21 Differential Transmission


Differential Group Delay




Scc21 Commonmode Transmission


Commonmode power ratio







CDLD30R (Actual Measurement) 
Sdd21 Differential Transmission


Differential Group Delay




Scc21 Commonmode Transmission


Commonmode power ratio







Technical Note 2:
Example of CommonMode Noise Elimination
For transmission speeds in excess of 10Gbps, even a minor skew will cause commonmode noise. Below is the circuit used to produce the commonmode noise wave form.
A CDLDtype is inserted directly after the IC, the GHz band commonmode noise is eliminated and transmission noise is prevented from returning to the original level.


(＊) ESD Protection Diode etc. 
(A) 28Gbps PseudoRandom Bit Sequence, Skew:10ps, CL:0.5pF, Channel Length:30mm 
Thru 

CDLD03E (1)* 
CDLD07R (1)* 




Noise amplitude[Xaxis:500ps/div,Yaxis:500mV/div]
Spectrum[Xaxis:2GHz/div,Yaxis:10mV/div] 




(B) 16Gbps PseudoRandom Bit Sequence, Skew:20ps, CL:1.0pF, Channel Length:100mm 
Thru 

CDLD04E (2)* 
CDLD10R (1)* 




Noise amplitude[Xaxis:500ps/div,Yaxis:500mV/div]
Spectrum[Xaxis:2GHz/div,Yaxis:10mV/div] 




(C) 10Gbps PseudoRandom Bit Sequence, Skew:25ps, CL:1.5pF, Channel Length:100mm 
Thru 

CDLD06E (1)* 
CDLD10R (1)* 




Noise amplitude[Xaxis:500ps/div,Yaxis:500mV/div]
Spectrum[Xaxis:2GHz/div,Yaxis:10mV/div] 




(1)* Sparameter Actual Measurement
(2)* Sparameter Electromagnetic Field Analysis

Technical Note 3:
Example of Differential Signal Balance Improvement
The wave form at the receiver will degrade due to skew or a connector GND discontinuity. The positive/negative differential signal wave forms of such a case are shown using the circuit below.
By using the CDLD with a passive internal CTLE, in addition to skew cancelation and improvement of the phase balance, it is also possible to cancel amplitude differences.


(＊) ESD Protection Diode etc.

(A) 25Gbps PseudoRandom Bit Sequence, Skew:10ps, CL:0.5pF, Channel Length:30mm 

Thru 

CDLD03E(1)* 






[Xaxis:100ps/div, Yaxis:500mV/div] 
(B) 16Gbps PseudoRandom Bit Sequence, Skew:15ps, CL:1.0pF, Channel Length:100mm 

Thru 

CDLD04E(2)* 






[Xaxis:200ps/div, Yaxis:500mV/div] 
(C) 10Gbps PseudoRandom Bit Sequence, Skew:25ps, CL:1.5pF, Channel Length:100mm 

Thru 

CDLD06E(1)* 






[Xaxis:200ps/div, Yaxis:500mV/div]

(1)* Sparameter Actual Measurement
(2)* Sparameter Electromagnetic Field Analysis

Technical Note4:
Comparison of Common Mode Noise Input Reflection 
For transmission speeds under 10Gbps, Commonmode Choke Coils are available; however, the reflection from the Commonmode Noise which is blocked by the Commonmode Choke Coil is quite large, the spike on the input wave form from the reflected Commonmode Noise will be superimposed. Using a comparator to compare the input and output wave forms, this superimposed noise can be quite detrimental. The positive/negative input wave forms of such a case are shown using the circuit below.
The CDLDtype’s ability to absorb the Commonmode Noise in the GHz band is quite high which prevents the superimposition of Commonmode Noise reflections on the input wave form.







(A) 10Gbps PseudoRandom Bit Sequence, Skew:20ps 

Common mode choke coil (1)* 

CDLD10R (2)* 






[Xaxis:200ps/div, Yaxis:500mV/div] 





(B) 5Gbps PseudoRandom Bit Sequence, Skew:30ps 

Common mode choke coil (1)* 

CDLD30R (2)* 






[Xaxis:500ps/div, Yaxis:500mV/div] 





(C) 2.5Gbps PseudoRandom Bit Sequence (3)*, Skew:50ps 

Common mode choke coil (1)* 

CDLD30R (2)* 






[Xaxis:1ns/div, Yaxis:500mV/div] 
(1)* Equivalent circuit created by a circuit simulator.
(2)* Sparameter Actual Measurement.
(3)* CDLD30R corresponding transmission speed is 4G～8Gbps; however, when used to prevent Common Mode Noise reflection, depending on the frequency of the noise, effectiveness at lower transmission speeds is also shown.






Technical Note5:
Step Response Skew Improvement Example

Using a TDR Sampling Oscilloscope, we constructed and measured the test circuits shown below, positive/Negative（In(+)／In()／Out(+)／Out()), output commonmode noise（Comm）and the output differential signal（Diff）step response wave forms are shown. The CDLDtype, which contains a delay mechanism, delays the noise from the output waveform and avoids affecting the rise/fall edge. 

Skew of signal source: 60ps





CDLD00R (Jumper)









In/Out/Comm[Yaxis:100mV/Div]
Diff[Yaxis:200mV/Div] 
CDLD30R 








In/Out/Comm[Yaxis:100mV/Div]
Diff[Yaxis:200mV/Div] 





(C) Commonmode choke coil 








In/Out/Comm[Yaxis:100mV/Div]
Diff[Yaxis:200mV/Div] 



Technical Note 6:
Frequency Characteristics of CommonMode Impedance

For the CDLDtype and the ideal commonmode choke coil (hereafter, ideal CMC), the frequency characteristics of commonmode impedance are calculated with a circuit simulator and the difference is verified. The equivalent circuit and the main characteristics of the ideal CMC are shown in Fig. 1. As much as possible, the －3dB passband was made wideband. 

3dB passband: 16.6GHz


Fig.1 Equivalent circuit and main characteristics o the ideal CMC

The method utilized for calculating commonmode impedance is shown below.
In general, commonmode impedance (Zcom)Fig. 2, is generated by a commonmode choke coilfrom commonmode noise. That value can be calculated from this circuit. Conversely, because the structure of the CDLDtype absorbs and removes the commonmode noise within the Signal LineGND circuit, commonmode impedance (Zcom) can be calculated from the circuit arranged and shown in Fig. 3.
Fig. 4 shows the frequency characteristics of the
ideal CMC and CDLD30R Commonmode impedance from the calculation circuits in Figs. 2 and 3. Here, the ideal CMC uses a circuit
simulation Sparameter while the CDLD30R uses an Sparameter measured with a 4port network analyzer.


Fig.2

Generation chart and calculation
commonmode choke coil Zcom


Fig.3

Generation chart and calculation
circuit of CDLD type Zcom


The ideal CMC intercepts the commonmode noise by generating high impedance within the signal line. As shown in Fig. 4, it appears to be effective in the vicinity of 2GHz. However, the inclination of the frequency characteristics is quite steep. Commonmode impedance is reduced as it diverges from 2GHz, and the intercept function decreases.
On the other hand, the CDLD30R is set to the value from the signalGND circuit corresponding to the commonmode impedance which is constant and small and has a fairly smooth frequency response. There appears to be an advantage to being able to lower the dependency on the frequency and to do a wideband absorptive removal of the commonmode noise.

Fig.4 Frequency characteristics of
Commonmode impedancec





Technical Note 7:
CDLD Transmission Speed

The differential frequency characteristics (Sdd21) of a differential transmission line with a 30ps skew are shown in Fig. 1. In Fig. 1, a differential signal is intercepted to become a complete common mode signal at 16.7GHz because the 30ps skew makes a 180° phase shift at that frequency. Transmission of the differential signal forms an attenuation pole at 16.7GHz and the －3dB passband becomes DC to 8.3GHz. 

－3dB Passband: DC～8.3GHz 
Fig. 1 Differential frequency characteristics (Sdd21) of differential transmission line with 30ps Skew 


0s Skew (－3dB Passband: DC～12.0GHz) 

30ps Skew (－3dB Passband: DC～6.8GHz) 

Fig.2 Differential frequency characteristics (Sdd21) with CDLD15R connected in the differential transmission line shown in above. 


Next, the CDLD15R frequency characteristics of the differential input signal skew of 0s, 30ps are shown in Fig. 2.
In Fig. 2, compared to the －3dB passband of 0s skew, the －3dB passband of 30ps skew is greatly reduced. However, as clearly indicated in Fig. 1, the cause is not due to the effects of the CDLD15R; rather, it is determined by skew generated by the transmission line. That is, the quality of the differential output waveform probably does not depend on the CDLD －3dB passband. Rather, it depends on the value of the skew when the CDLD is connected for skew cancellation. It can be assumed to become like the sine wave to which the highorder harmonic is missed in 1Unit Interval corrugating according to the transmission speed. Especially at speeds of more than 10Gbps, the trend is more noticeable.
Therefore, the corresponding transmission speed of CDLD is not calculated simply from its －3dB passband, when the skew was generated, the maximum value at the correspondence transmission speed to which output waveform fineness was able to be maintained was examined on the assumption that passing waveform at 1Unit Interval became like the sine wave according to the characteristic of Fig. 1.
As a result, we judged that it was possible to correspond enough up to the transmission speed described in the specifications.
In addition, our CSKFtype not only cancels the skew but also restores the differential transmission signal. If the rough skew is canceled by the CSKFtype and the residual skew is canceled by the CDLD, it is possible to balance the differential signal completely.

RoHS Compliance Status

RoHScompliant

Notes

Always connect the GND terminals. Using this product without connecting the GND could cause common mode noise rejection and delay line functions to deteriorate.
Use of only one line will not yield a normal wave form and cannot be used.



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