UC5607
Plug and Play, 18-Line SCSI Active Terminator
FEATURES
DESCRIPTION
• Complies with SCSI and SCSI-2
Standards
The UC5607 provides 18 lines of active termination for a SCSI (Small
Computer Systems Interface) parallel bus. The SCSI standard recom-
mends active termination at both ends of the cable segment.
• 8pF Channel Capacitance during
Disconnect
The UC5607 provides a low disconnect feature which will disconnect all
terminating resistors, and will disable the regulator, greatly reducing
standby power. The output channels remain high impedance even without
Termpwr applied.
• SCSI Plug and Play, Dual Low
Disconnect, Logic Low Command
Disconnects All Termination Lines
The UC5607 terminator is specially designed with two disconnect pins for
full SCSI Plug and Play (PnP) applications.
• Meets SCSI Hot Plugging Capability
• -650mA Sourcing Current for
Termination
Custom power packages are utilized to allow normal operation at full
power conditions (2 Watts).
• +200mA Sinking Current for Active
Negation
Internal circuit trimming is utilized, first to trim the impedance to a 7% tol-
erance, and then most importantly, to trim the output current to a 7% toler-
ance, as close to the max SCSI spec as possible, which maximizes noise
margin in fast SCSI operation.
• 200µA Supply Current in Disconnect
Mode
Other features include thermal shutdown and current limit.
• Trimmed Termination Current to 7%
• Trimmed Impedance to 7%
This device is offered in low thermal resistance versions of the industry
standard 28 pin wide body SOIC, and 28 pin PLCC, as well as 24 pin DIP.
• Provides Active Termination for 18
Lines
BLOCK DIAGRAM
Connect Connect Connect
Disc
DISCNCT1
DISCNCT2
1
0
0
1
1
1
0
0
UDG-94124
Circuit Design Patented
7/98