TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

Page 1

SEARAY Flex Assembly High-Speed Electrical Performance

Date: 10/11/2006 Document: TS-xxxxx-001 Revision: 1.0

By Jeff Ciarlette Electrical Engineer Printed Circuit Products

Disclaimer: Molex does not guarantee the performance of the final product to the information provided in this document. All information in this report is considered Molex proprietary and confidential. Assignment of the terminal to signal configurations other than that specified in this document is not recommended.

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

Page 2

TABLE OF CONTENTS SEARAY Flex Assembly .............................................................................................................................1 I. Test Fixture .............................................................................................................................................3

Test Boards ................................................................................................................................................3 Test Equipment ..........................................................................................................................................3 Device Under Test......................................................................................................................................4

II. Time Domain Analysis..........................................................................................................................5 TDR Impedance Data.................................................................................................................................5 Near End Cross Talk ..................................................................................................................................6 Near End Cross Talk (continued)...............................................................................................................7 Far End Cross Talk ....................................................................................................................................8

III. Frequency Domain Analysis..........................................................................................................10 Insertion Loss ...........................................................................................................................................10 Return Loss ..............................................................................................................................................11

IV. Discussion........................................................................................................................................12 TABLE OF FIGURES Figure 1: Male Test Board ............................................................................................................................3 Figure 2: Female Test Board & Calibration Traces.....................................................................................3 Figure 3: Test Board Pinout ..........................................................................................................................4 Figure 4: Differential Impedance ..................................................................................................................5 Figure 5: Cross Talk Configuration ..............................................................................................................6 Figure 6: Worse Case 2.8” Trace NEXT ......................................................................................................7 Figure 7: Worse Case 14.8” Trace NEXT ....................................................................................................7 Figure 8: Worse Case 2.8" Trace FEXT .......................................................................................................8 Figure 9: Worse Case 14.8” Trace FEXT .....................................................................................................8 Figure 10: 10Gbps PRBS Pattern through 2.8" Trace ..................................................................................9 Figure 11: 10Gbps PRBS Pattern through 14.8" Trace ................................................................................9 Figure 12: Differential Insertion Loss with 2.8” Trace...............................................................................10 Figure 13: Differential Insertion Loss with 14.8" Trace.............................................................................10

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

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I. Test Fixture Test Boards The test fixture consisted of two test boards – one with a male connector and the other with a female connector. The test boards were constructed with NELCO-12 dielectric and utilized a strip line construction with length matched traces. Calibration traces from the same panel as the test board was used to calibrate out some of the test fixture error.

Figure 1: Male Test Board

Figure 2: Female Test Board & Calibration Traces

Test Equipment Tektronix TDS8000 Digital Sampling Oscilloscope Agilent 8722ES S-Parameter Network Analyzer

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

Page 4

Device Under Test The DUTs six flex assemblies with a male SEARAY connector on one end and a female SEARAY connector on the other end. Three of these assemblies were approximately three inches long and the other three were approximately 15 inches long. Construction details are listed below.

MATERIAL POLYIMIDE CONSTRUCTION STRIPLINE TRACE LENGTH 2.8” AND 14.8”

8 6 5 1

16 16 15 12 11 9

24 22 21 18 17 17

32 32 31 28 27 25

40 38 37 33

48 41

56 49

64 57

72 65

80 73

88 81

96 89

104 97

112 105

120 113

128 121

136 129

144 141 139 137

152 149 147 145 145

160 56 154 153

Differential Signals

Ground Test Board Connections

Figure 3: Test Board Pinout

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

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II. Time Domain Analysis TDR Impedance Data The following graphs show the impedance profile of the assembly launch. They include the test boards and connectors. Only the near end is shown. The rise time used was 40ps 10% to 90%. The impedance profile below is typical. Most profiles have peaks within 2 ohms of the values below.

Figure 4: Differential Impedance

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

Page 6

Near End Cross Talk In these measurements the victim and the aggressor are on the same test board. The test board at the far end is terminated to 100 ohms differential. The aggressor was 500mVpp. Figure 5: Cross Talk Configurationshows a portion of the connector pinout configuration. The yellow pair was the victim for the measurements. Each red pair was an aggressor. Only one aggressor pair was active at a time.

8 6 5 1

16 12 11 9

24 22 21 18 17 17

32 25

40 33

48 41

56 49

64 57

Differential Signals

Ground

Victim

Agressor

Figure 5: Cross Talk Configuration

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

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Near End Cross Talk (continued)

Figure 6: Worse Case 2.8” Trace NEXT

Figure 7: Worse Case 14.8” Trace NEXT

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

Page 8

Far End Cross Talk In these measurements the victim and the aggressor are on opposite test boards. The other ends are terminated to 100 ohms differential. The aggressor was 500mVpp.

Figure 8: Worse Case 2.8" Trace FEXT

Figure 9: Worse Case 14.8” Trace FEXT

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

Page 9

Eye Diagrams Below are typical eye diagrams from a short and long flex. The eye diagrams were derived from the frequency data (see Frequency Domain Analysis).

Figure 10: 10Gbps PRBS Pattern through 2.8" Trace

Figure 11: 10Gbps PRBS Pattern through 14.8" Trace

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

Page 10

III. Frequency Domain Analysis A TLR type calibration was performed before the frequency measurements were taken. The test board SMA connector and some of the test board trace are compensated for through the calibration. The calibration plane is one inch from the SEARAY connector. Insertion Loss

Differential Insertion Losswith 2.8" trace

-22-21-20-19-18-17-16-15-14-13-12-11-10-9-8-7-6-5-4-3-2-10

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

Frequency (MHz)

Inse

rtio

n L

oss

(d

B)

DUT 1 SDD12Pins 11&12

DUT 2 SDD12Pins 11&12

DUT 3 SDD12Pins 11&12

DUT 1 SDD12Pins 27&28

DUT 2 SDD12Pins 27&28

DUT 1 SDD21Pins 11&12

DUT 2 SDD21Pins 11&12

DUT 3 SDD21Pins 11&12

DUT 1 SDD21Pins 27&28

DUT 1 SDD21Pins 27&28

Figure 12: Differential Insertion Loss with 2.8” Trace

Differential Insertion Losswith 14.8" trace

-22-21-20-19-18-17-16-15-14-13-12-11-10-9-8-7-6-5-4-3-2-10

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

Frequency (MHz)

Inse

rtio

n L

oss

(d

B)

DUT 1 SDD12Pins 11&12

DUT 2 SDD12Pins 11&12

DUT 3 SDD12Pins 11&12

DUT 2 SDD12Pins 27&28

DUT 3 SDD12Pins 27&28

DUT 1 SDD21Pins 11&12

DUT 2 SDD21Pins 11&12

DUT 3 SDD21Pins 11&12

DUT 2 SDD21Pins 27&28

DUT 3 SDD21Pins 27&28

Figure 13: Differential Insertion Loss with 14.8" Trace

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

Page 11

Return Loss Return loss measurements are shown up to 12GHz.

Differential Return Losswith 2.8" trace

-60

-50

-40

-30

-20

-10

0

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

Frequency (MHz)

Ret

urn

Lo

ss (d

B)

DUT 1 SDD11Pins 11&12

DUT 2 SDD11Pins 11&12

DUT 2 SDD11Pins 11&12

DUT 1 SDD11Pins 27&28

DUT 3 SDD11Pins 27&28

DUT 1 SDD22Pins 11&12

DUT 2 SDD22Pins 11&12

DUT 3 SDD22Pins 11&12

DUT 1 SDD22Pins 27&28

DUT 2 SDD22Pins 27&28

Figure 8: Differential Return Loss with 2.8” Trace

Differntial Return Loss

with 14.8" trace

-60

-50

-40

-30

-20

-10

0

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

Frequency (MHz)

Ret

urn

Lo

ss (d

B)

DUT 1 SDD11Pins 11&12

DUT 2 SDD11Pins 11&12

DUT 3 SDD11Pins 11&12

DUT 2 SDD11Pins 27&28

DUT 3 SDD11Pins 27&28

DUT 1 SDD22Pins 11&12

DUT 2 SDD22Pins 11&12

DUT 3 SDD22Pins 11&12

DUT 2 SDD22Pins 27&28

DUT 3 SDD22Pins 27&28

Figure 9: Differential Return Loss with 14.8" Trace

TEST REPORT SEARAY Flex Assembly

MOLEX INCORPORATED 2222 WELLINGTON COURT, LISLE, IL 60532-1682

TEL 630-969-4550 FAX 630-969-4550 TLX 254069

Page 12

IV. Discussion As can be seen from the data, the SEARAY flex assembly can be a very effective high speed solution. The short flex has a 3dB bandwidth of approximately 5GHz (fundamental frequency of 10Gbps data). At 5GHz, the 15” assembly has only 7.5dB of attenuation. Modern transceivers such as those found in high-end FPGAs employ pre-emphasis and/or equalization to realize receiver sensitivities far greater than 7.5dB. Assuming there is a linear increase in loss with an increase in the flex length, the data from the two different trace lengths can be interpolated to provide a good estimate of attenuation for a given length at a given frequency. For example at 5GHz, we know at 2.8” there is 3dB of loss and 7.5dB at 14.8”. Below, two equations with two unknowns are simultaneously solved to yield an estimate of loss pre linear trace length at 5GHz.

x + 2.8y = 3 where x is the fixed loss (interconnect) x + 14.8y = 7.5 y is the loss per length y = 0.375 x = 1.95

To solve for loss of any length at 5GHz the equation becomes: a = 1.95 + 0.375b where a is the insertion loss in dB b is the length of the differential pair in inches

To solve for maximum length at 5GHz for a given loss budget the equation becomes:

b = (a – 1.95) / 0.375 where a is the insertion loss in dB b is the length of the differential pair in inches Data was also taken for single ended traces, but not presented here. The single ended performance was similar to the differential. Since most single ended data is transmitted at much lower speeds, the high performance of this flex is only valuable in that there is the potential to run a very long trace or in cases where the loss budget is prohibitively low.