Download section 1 - Artisan Technology Group

ANCOT Corporation
User=s Manual
SCSI Bus Analyzer Ultra-2000: Appendix H
The Differential interface is electrically more robust, therefore there was no
need to develop a more expensive active type terminator.
H.3.3
LVD - LOW VOLTAGE DIFFERENTIAL ALTERNATIVE
This alternative uses transfers over two electrically symmetrical lines
denoted +SIGNAL and -SIGNAL.
"True" signal is defined as +SIGNAL more
positive than -SIGNAL, the "False" signal is defined as +SIGNAL more negative
than -SIGNAL.
LVD termination: (active type)
o +2.7 - 5.25 Volt (TERMPWR)
│
60
│
150 ┌──VVVV─── D0│
┌─VVVV──┤
│
┌───────────┐
1.25V
│
└──VVVV───D0+
└─────┤Vin
Vout ├─────────────────┤ .
3│
RD'J │2
. .
└─────┬─────┘
.
│1
.
┌──VVVV── REQ│
└─VVVV──┤
?
└──VVVV── REQ+
NOTE & WARNING:
It is important to remember that the terminator must match the interface type:
single-ended interfaces must use single-ended terminators; differential
interfaces must use differential terminators.
In case of single-ended
terminators, there are two types available: 'passive' and 'active'.
The
'active' type SE terminator is electrically better since it provides higher
noise immunity.
It is permissible to mix the two S-E terminator types: you
can use the 'passive' type on one end of the SCSI cable, and the 'active' type
on the other end of the same cable.
129
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com