External Mini SAS/SATA Cable Assembly · SI-2008-06-006 External Mini SAS/SATA 3 Test Set-up Three different wire gauges were tested (28, 26, and 24AWG). All cables were passive and

External Mini SAS/SATA Cable

Assembly

SI-2008-06-006 Revision 1 August-27-2008

2SI-2008-06-006 External Mini SAS/SATA

Introduction

The purpose of these tests was to show compliance of FCI’s external

mini-SAS/SATA cable assemblies to the Serial ATA Revision 2.6 and

T10/1760-D Revision 10 SAS-2 requirements.

Measurement parameters

Connector and Cable Differential Impedance

Raw Cable Pair Matching Impedance

Raw Cable Common Mode Impedance

Insertion Loss

Frequency-Domain Single-Active and Multi-Active Near-End Crosstalk

Intra pair skew (within pair skew)

Inter-Symbol Interference (Jitter)

Equipment Used

Digital Sampling Oscilloscope Tektronix CSA 8000B

4-port VNA (HP8720ES and ATN-4112A S-parameter test set)

Advantest D3186 12 Gbps Pattern Generator


Test Set-up

Three different wire gauges were tested (28, 26, and 24AWG). All cables

were passive and un-equalized. The test boards used to complete the testing

(P/N 739312544) had all 8 differential pairs routed. These 4-layer boards

have trace lengths of 50.5mm and trace widths of 12mils (0.3048mm).

Test Board

Measurement Set-up


Connector and Cable Differential Impedance

The differential impedance was measured using a CSA8000B Digital Sampling

Oscilloscope. The data was measured at 30 ps (20-80%) risetime and filtered

to the required 70 ps (20-80%). The following impedance profiles represent

the expected impedance for the FCI External Mini SAS/SATA cable assembly.

Differential Impedance (System risetime 70ps 20-80%)

85

90

95

100

105

110

115

Time (500ps/Div.)

Ohms

26 AWG

24 AWG

28 Mated Connector Differential Impedance Upper Limit

Mated Connector Differential Impedance Lower Limit

Cable Absolute Differential Impedance Upper Limit

Cable Absolute Differential Impedance Lower Limit

AWG

AWG

AWG


Competitive Connector and Cable Differential Impedance

Competitor B Differential Impedance (System risetime 70ps 20-80%)

80

85

90

95

100

105

110

115

120

Time (200ps/div.)

Ohms

Mated Connector

Mated Connector

Cable Absolute Differential

Impedance Lower Limit


Impedance Upper Limit

Txs of Competitor B 24 AWG

Rxs of Competitor B 28 AWG

Txs of Competitor B 28 AWG

Rxs of Competitor B 24 AWG

Competitor A Differential Impedance (System risetime 70ps 20-80%)

80

85

90

95

100

105

110

115

120

Time (200ps/div.)

Ohms

Mated Connector

Mated Connector


Impedance Lower Limit


Impedance Upper Limit

Txs of Competitor A 24 AWG

Rxs of Competitor A 28 AWG

Txs of Competitor A 28 AWG

Rxs of Competitor A 24 AWG


Common-mode Impedance (System risetime 70ps 20-80%)

20

25

30

35

40

45

50

Time (500ps/Div.)

Ohms

Common Mode Minimum Lower Limit

Common Mode Maximum Upper Limit

26

AWG

24

AWG

28

Raw Cable Common Mode Impedance

The common mode impedance was measured using a CSA8000B Digital

Sampling Oscilloscope. The data was measured at 30 ps (20-80%) risetime

and filtered to the required 70 ps (20-80%). The following impedance profiles

represent the expected impedance for the FCI External Mini SAS/SATA cable

assembly.

AWG

AWG

AWG


Raw Cable Pair Matching

Cable Pair Matching (System risetime 70ps 20-80%)

50

52

54

56

58

60

Time (500ps/div.)

Ohms

26

AWG

24 AWG

28

The pair matching was measured using a CSA8000B Digital Sampling

Oscilloscope. The data was measured at 30 ps (20-80%) risetime and filtered

to the required 70 ps (20-80%). The following impedance profiles represent

the expected impedance for the FCI External Mini SAS/SATA cable assembly.

All cable met the required ± 5 ohms.

AWG

AWG

AWG


Differential Insertion Loss

The differential insertion loss of the cable assemblies was

measured with an HP8720ES/ATN-4112A 4-Port Network

Analyzer (according to the SAS and SATA specifications.)

The loss results for of the connector and cable compared to

the SAS and SATA insertion loss requirements are shown

on the following slides.


0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0Differential Insertion Loss with the PCB loss removed

Frequency (GHz)

Differential Insertion Loss (dB)

SATA Differential Insertion Loss results

28 AWG 1m

26 AWG 5m

SATA ≤≤≤≤2m Limit

SATA >2m Limit

24 AWG 6m

28 AWG 3m

26 AWG 2m


0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0Differential Insertion Loss with the PCB loss removed

Frequency (GHz)

Differential Insertion Loss (dB)

SAS Differential Insertion Loss results

26 AWG 5m

SAS Limit

24 AWG 6m

28 AWG 3m


Differential Crosstalk

Frequency-Domain crosstalk measurements were taken

with an HP8720ES/ATN-4112A 4-Port Vector Network

Analyzer.

Multi-Active Near-end measurements were performed with

TX0, TX1, TX2, and TX3 active and listening to RX0, RX1,

RX2, and RX3.

Single-Active Near-end measurements were performed

listening to RX0 and exciting pairs RX1, RX2, and RX3.

Both the expected frequency-domain single active and multi-

active results are shown on the following slides.


Single-Active Near-end Crosstalk results

SAS Limit

SAS Limit

SAS Limit

26 AWG 3m

24 AWG 1m

28 AWG 5m


Multi-Active Near-End Crosstalk results

SAS Limit

SATA Limit

26 AWG 3m

24 AWG 1m

28 AWG 5m


Competitor A 24 AWG

Competitor B 28 AWG Competitor B 24 AWG

Competitor A 28 AWG

Competitive Multi-Active Near-End Crosstalk results


Intra-Pair Skew (Within Pair Skew)

The skew was obtained by measuring the delay of each single-ended signal

within a pair at the mid point of the voltage swing according to the SATA

requirement. The skew was measured with a CSA 8000B Digital Sampling

Oscilloscope. The measurement was performed by using a differential TDT

step into each differential cable pair. All cables met the maximum SAS skew

specification of 50 ps and the SATA requirement of 20ps.

Pair AVG Skew (ps)

24 AWG 6m 20

26 AWG 5m 15

28 AWG 3m 10

Intra-pair Skew (ps)


Inter-Symbol Interference (Jitter)

The following eye patterns present a visual representation of the effect that the FCI

External Mini SAS/SATA cable assemblies have on an actual data stream. These

measurements were obtained using an Advantest D3186 12 Gbps Pattern Generator,

and a Tektronix CSA 8000B Digital Sampling Oscilloscope. A differential CJTPAT bit

pattern was used to excite the assembly. The maximum allowable jitter the SATA

requirement permits for cables 2 meters or less is 50 ps. The maximum allowable

jitter the SATA requirement permits for cables longer then 2 meters is 60 ps. The maximum allowable jitter the SAS requirement permits for all cable lengths is 60 ps.

3Gbps Calibration Trace Jitter = 10ps


28AWG Sample ISI results

3Gbps 28 AWG 1meterJitter = 15ps



26 and 24AWG Sample ISI results




Conclusion

Performance Level 1m 2m 3m 4m 5m 6m

SAS 28 28 28 26 26 24

SATA 28 26 28 26 26 24

Unequalized Cable Length

Verified

Documents

External Mini SAS/SATA Cable Assembly · SI-2008-06-006 External Mini SAS/SATA 3 Test Set-up Three different wire gauges were tested (28, 26, and 24AWG). All cables were passive and