Seagate ST373207LW/LC, ST3146707LW/LC manual Cables for low voltage differential drivers/receivers

Page 92

Single-ended I/O cable pin assignments for LW drives are shown in Table 15.

Single-ended I/O pin assignments for LC models are shown in Table 16. The LC model does not require an I/O cable. It is designed to connect directly to a back panel connector.

9.7.1.3Cables for low voltage differential drivers/receivers

The SPI-3 and SPI-4 specification for differential impedance for LVD cables is 122.5 ± 12.5 ohms.

The maximum SCSI bus length between the terminators for a SCSI LVD point-to-point system (one initiator and one target) is 25 meters (82 feet).

The maximum SCSI bus length between the terminators for a SCSI LVD multidrop system (up to 16 total SCSI devices) is 12 meters (39.37 feet). However, implementation of this 12-meter total length is dependent on the configuration of the system and the choice of cable. See Tables 19 and 20 for examples of recommended SCSI LVD cable types and lengths.

It should be noted from the data in Tables 19 and 20 that shielded round twisted-pair cables can be used to implement a 12-meter system, while Twist-n-flat cables cannot be used to implement a 12-meter system due to higher levels of attenuation and crosstalk. In addition, twist-n-flat cables with shorter sections of twist allow greater crosstalk and their lengths must be reduced as shown in Table 20.

Table 19:

Example shielded round twisted-pair cables - into a multi-drive backplane

 

 

 

 

 

 

 

 

 

 

 

Single-

Single-

 

Conductor

 

 

 

Differential

ended

ended

Time

DC

Maximum shielded round

Cable

 

impedance,

impedance,

capacitance,

delay,

resistance,

twisted-pair cable length

description

 

nominal

nominal

maximum

nominal

nominal

for U160/U320

 

 

 

 

 

 

 

 

30 AWG

 

130 ohms

90 ohms

17 pF/ft

1.36 ns/ft

0.113 ohms/ft

12 meters minus the SCSI

solid

 

 

 

 

 

 

trace length of the backplane

 

 

 

 

 

 

 

 

28 AWG

 

123 ohms

80 ohms

19 pF/ft

1.54 ns/ft

0.067 ohms/ft

12 meters minus the SCSI

stranded

 

 

 

 

 

 

trace length of the backplane

 

 

 

 

 

 

 

 

28 AWG

 

132 ohms

85 ohms

20 pF/ft

1.50 ns/ft

0.065 ohms/ft

12 meters minus the SCSI

stranded

 

 

 

 

 

 

trace length of the backplane

 

 

 

 

 

 

 

 

82

Cheetah 10K.7 SCSI Product Manual, Rev. D

Page 91 Page 93
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Contents
Cheetah 10K.7 Scsi Page Cheetah 10K.7 Scsi Page Revision status summary sheet Page Contents Defect and error management InstallationSeagate Technology support services Interface requirementsList of Figures Viii Cheetah 10K.7 Scsi Product Manual, Rev. D Scope Cheetah 10K.7 Scsi family drive ST3300007LC shownCheetah 10K.7 Scsi Product Manual, Rev. D Applicable standards and reference documentation StandardsElectromagnetic compatibility Electromagnetic susceptibilityElectromagnetic compliance European Union Restriction of Hazardous Substances RoHSReference documents Cheetah 10K.7 Scsi Product Manual, Rev. D General description Standard features Media characteristicsFormatted capacities PerformanceReliability Factory installed accessories Options factory installedAccessories user installed Programmable drive capacityScsi performance characteristics visible to user Performance characteristicsInternal drive characteristics transparent to user Access time Format command execution time minutesGeneralized performance characteristics Ultra320 ScsiCache operation Start/stop timePrefetch/multi-segmented cache control Caching write data Prefetch operation Cheetah 10K.7 Scsi Product Manual, Rev. D Reliability specifications Error ratesRecoverable Errors Unrecoverable ErrorsReliability and service Seek errorsPreventive maintenance Annualized Failure Rate AFR4 S.M.A.R.T Controlling S.M.A.R.TPerformance impact Reporting controlDetermining rate Predictive failuresParameter Code Description Drive Self Test DSTState of the drive prior to testing DST Failure DefinitionImplementation Invoking DSTProduct warranty Short test Function Code 001bExtended test Function Code 010b Log page entriesShipping Product repair and return informationDC power requirements Physical/electrical specificationsAC power requirements ST3146707 SE mode LVD mode 3 12 V Current profile Power sequencingConducted noise immunity Typical ST3300007 drive +12 V current profile Typical ST3146707 drive +12 V current profile Typical ST373207 drive +12 V current profile Power dissipation ST3300007ST3146707 ST373207 Temperature Environmental limitsRelative humidity Effective altitude sea levelShock and vibration ShockRecommended mounting Corrosive environment Air cleanlinessVibration Mechanical specifications AcousticsLW mounting configuration dimensions LC mounting configuration dimensions Drive internal defects Defect and error managementDrive error recovery procedures Page Scsi systems errors Background Media Scan Media Pre-ScanInstallation Configure drive optionsDrive ID/option select header FormattingJ6 jumper header J5 jumper header on LW models only J2 option select header on LW models only Function description RESDrive orientation CoolingDrive mounting GroundingCheetah 10K.7 Scsi Product Manual, Rev. D Scsi interface messages supported Interface requirementsGeneral description Scsi interface commands supported Page Page Page Inquiry Vital Product data Mode Sense data Mode Sense 10 Byte Header Data 00 ae 00 10 00 00 00 08 11 17 73 30 00 00 02 00 ae 00 10 00 00 00 08 08 8b b9 98 00 00 02 Scsi bus conditions and miscellaneous features supported Condition/feature supported bySynchronous data transfer Physical interfaceSynchronous data transfer periods supported 2 REQ/ACK offsetDC cable and connector PCB Scsi interface physical description Mating connectors Scsi interface cable requirementsCable requirements LC ModelsMating connectors for LW model drives Mating connectors for LC model drivesRight-angle to Pcba connectors Scsi daisy chain interface cabling for LW drives Nonshielded 68-pin Scsi device connector used on LW drives Nonshielded 80-pin Scsi SCA-2 connector, used on LC drives GND +DBP1 Charge Active LED OUT 4 REQ +REQ Active LED OUT 4 Multimode-SE and LVD alternatives LVD output characteristicsElectrical description Single-ended drivers/receivers LVD input characteristicsGeneral cable characteristics Cables for low voltage differential drivers/receivers LC drives Terminator requirements Terminator powerLW drives Disc drive Scsi timing Disc drive Scsi timing Spindle status Command status LED status Drive activity LEDSeagate Technology support services Internet MySeagate Reseller.seagate.comPresales Support Technical SupportData Recovery Services Warranty ServiceData Recovery Services Authorized Service Centers Toll-free support numbers FAX services-All Europe toll callCall center Presales and Technical Support Warranty Service Asia/Pacific support services Publication feedback survey Cheetah 10K.7 Scsi Product Manual, Rev. D Symbols NumericsPage Page PCB Page Cheetah 10K.7 Scsi Product Manual, Rev. D
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