
2.8.2
Passive termination
All interface signals with the drive are single-ended and must be termi-
nated with 220 ohms to +5V and 330 ohms to ground at each end of the
cable. All signals use open-collector drivers or three-state drivers. The
Seagate part number for the 220/330-ohm terminator is 75916526-9.
Single-ended SCSI devices providing termination power have the follow-
ing characteristics:
Terminator voltage (V)
4.0 to 5.25
Source drive capability (mA, min)
800
Line driver
(transmitter or transceiver)
+2.85V
110
ohms
+2.85V
110
ohms
Flat cable pair
Line receiver
ANSI SCSI
compatible
circuit
ANSI SCSI
compatible circuit
Figure 4. Active termination
Line driver
(transmitter or transceiver)
+5V
220
ohms
330
ohms
+5V
220
ohms
330
ohms
Flat cable pair
Line receiver
ANSI SCSI
compatible
circuit
ANSI SCSI
compatible circuit
Figure 5. Passive termination
ST3655 Family SCSI Drives Product Manual, Rev. A
21
Summary of Contents for ST3285N
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