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USER RESPONSIBLE FOR VERIFYING VERSION AND COMPLETENESS
OEM FUNCTIONAL SPECIFICATION ULTRASTAR XP (DFHC) SSA MODELS 1.12/2.25 GB - 1.0" HIGH
Termination
Bus termination of the - SYNC signals is internal to the drive. This signal has a 5.1K ohm pulled-up to
the + 5 volt supply. A maximum of 30 drives can have their - SYNC line daisy chained together. Vio-
lating this could damage the Master drive line driver on the - SYNC line
It is the using system's responsibility to provide the cable to connect the - SYNC line where needed, of
the synchronized drives.
Bus Characteristics
− maximum Bus length = 6 meters
− 2 micro-second negative active pulse (when sourced by drive)
− minimum of 1 micro-second negative active pulse when externally sourced
− 0.8 volts = valid low input
− 2.2 volts = valid high input
− 0.4 volts = low output
− Vcc volts = High output
− 30 milli-amps = maximum output low level sink current
The driver used for these two signal lines is a Open Drain buffer.
Source filename=SYNC IBM Corporation Page 71 of 87