Chapter 5
SCSI Physical Characteristics
Page 56
Filepro CFP2107 Series
Model CFP2107S (Narrow, 50-pin SCSI)
External Terminator Power
Power to the on-board terminators is provided by the higher of the voltage
supplied at Pin #26, J2 or the voltage level at the 5 Volt power input to the drive
minus one diode drop. The diode prevents back flow of current to the drive.
Termination Power to external terminators can be supplied by the drive through
Pin #26, J2. The TERMPWR line can be disconnected from the drive by
removing Jumper E8. Table 5-10 describes the electrical characteristics of the
TERMPWR line when it is used to supply power to an external terminator.
Table 5-11 describes the required electrical characteristics for any external
source of termination power.
Table 5-10
TERMPWR Output Electrical Characteristics
Signal Characteristic
Value
Supply voltage
4.06 VDC to 4.56 VDC
Minimum source capability:
800 mA (fused at 1000 mA)
Table 5-11
TERMPWR Input Electrical Characteristics
Signal Characteristic
Value
Input voltage
4.00 VDC to 5.25 VDC
Minimum source capability:
1000 mA (fused at 1000 mA)
Sink current:
1.0 mA maximum, excluding
power to the internal terminator.
Internal Termination
This drive provides on-board Alternative 2 active termination for the SCSI bus.
The termination resistors, which are contained in two Single Inline Packs (SIPs)
should be removed from the drive unless it is a SCSI device at a physical end of
the bus. The terminator equivalent circuit is shown below for reference:
Figure 5-1
Terminator Equivalent Circuit
+5V
TERMPWR
F1
2.5K
10K
-DB0
-DB1
-DB2
-REQ
-I/O
: :
: :
: :
110
Voltage
Regulator
E8
