UCC5672
Multimode (LVD/SE) SCSI 9 Line Terminator
FEATURES
•
Auto Selection Multi-Mode Single
Ended or Low Voltage Differential
Termination
•
2.7V to 5.25V Operation
•
Differential Failsafe Bias
•
Built-in SPI-3 Mode Change Filter/
Delay
•
Meets SCSI-1, SCSI-2, Ultra2 (SPI-2
LVD) and Ultra3/Ultra160 Standards
•
Supports Active Negation
•
3pF Channel Capacitance
DESCRIPTION
The UCC5672 Multi-Mode Low Voltage Differential and Single Ended Ter-
minator is both a single ended terminator and a low voltage differential ter-
minator for the transition to the next generation SCSI Parallel Interface
(SPI-3). The low voltage differential is a requirement for the higher speeds
at a reasonable cost and is the only way to have adequate skew budgets.
The automatic mode select/change feature switches the terminator be-
tween Single Ended or LVD SCSI Termination, depending on the bus
mode. If the bus is in High Voltage Differential Mode, the terminator lines
transition into a High Impedance state.
The UCC5672 is SPI-3, SPI-2, and SCSI-2 compliant. This device is of-
fered in a 28 pin TSSOP package to minimize the footprint. The UCC5672
is also available in a 36 pin MWP package.
BLOCK DIAGRAM
2.1V
DIFFB
17
0.6V
FILTER/
DELAY
HPD
LVD
SE
DIFSENS
REF 1.3V
ENABLE
SOURCE/SINK
REGULATORS
SE REF
2.7V
10µA
DISCNCT
13
LVD REF
1.25V
ENABLE
SE GROUND
SWITCH
110
HS/GND
HS/GND
GND
6
22
14
MODE
SE
LVD
HPD
DISCNCT
SW1
UP
DOWN
DOWN
OPEN
OTHER
SWITCHES
UP
DOWN
OPEN
OPEN
124
56mV
–
+
56mV
+
–
52
SW1
110
56mV
–
+
56mV
+
–
52
16
DIFSENS
TRMPWR
TRMPWR
28
27
124
3
52
2
L1–
L1+
26
52
25
L9–
L9+
SE GROUND
SWITCH
1
Note: Indicated pinout is for 28 pin TSSOP package.
REG
UDG-99125
SLUS414A - FEBRUARY 2000
TI [ TEXAS INSTRUMENTS ]
