Figure 12. Single-Ended Transmitters And Receivers - Seagate ST32151N Product Manual

62
9.6.4.4 Single-ended drivers/receivers
For "N" models which use single-ended drivers and receivers, typical circuits are shown in Figure 12. Termina-
tor circuits (Note [1]) are to be enabled (model N) only when the disc drive is first or last in the daisy-chain.
Transmitter characteristics
Single-ended drives use an ANSI SCSI compatible open collector single-ended driver. This driver is capable of
sinking a current of 48 mA with a low level output voltage of 0.4 volt.
Receiver characteristics
Single-ended drives use an ANSI SCSI single-ended receiver with hysteresis gate or equivalent as a line
receiver.
Line Driver
Transmitter
(or transceiver)
[2]
Figure 12. Single-ended transmitters and receivers
Notes.
[1] Part of active terminator circuits. Non-removable LSI terminators, enabled in the drive (model "N" and "W"
models only) with jumper plug TE when it is first of last in the daisy-chain. Interface signals levels and log-
ical sense at the drive I/O connector are defined as follows:
Logic Level
NEGATED (0)
ASSERTED (1)
The difference in the voltages between input and output signals is due to the losses in the cable.
[2] ANSI SCSI compatible circuits
[3] Total interface cable length should not exceed that specified in Section 9.6.3.1.
[4] Source of drive terminator power is an active circuit which has an input source voltage selected by jumper
plug TP. See Figure 7d. Applies to "N" and "W" models.
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TP
[4]
Flat
110
Cable
[1]
Ohm
Pair
[3]
Driver Output Receiver Input
>2.5 V: <5.25 V >2.0 V: <5.25 V
<0.4 V: >0.0 V <0.8 V: >0. 0 V
Hawk 2XL Product Manual, Rev. B
Line Receiver
TP
Receiver
[4]
110
[1]
Ohm
[2]