UCC5628 Datasheet, PDF (1/5 Pages) Texas Instruments – Multimode SCSI 14 Line Terminator

UCC5628
Multimode SCSI 14 Line Terminator
FEATURES
• Auto Selection Single Ended (SE) or
Low Voltage Differential (LVD)
Termination
• Meets SCSI-1, SCSI-2, SCSI-3, SPI,
Ultra (Fast-20), Ultra2 (SPI-2 LVD)
and Ultra3 Standards
• 2.7V to 5.25V Operation
• Differential Failsafe Bias
• Thermal packaging for low junction
temperature and better MTBF.
BLOCK DIAGRAM
DESCRIPTION
The UCC5628 Multimode SCSI Terminator provides a smooth transition
into the next generation of the SCSI Parallel Interface (SPI-2). It automati-
cally senses the bus, via DIFFB, and switches the termination to either sin-
gle ended (SE) or low voltage differential (LVD) SCSI, dependent on which
type of devices are connected to the bus. The UCC5628 can not be used
on a HVD, EIA485, differential SCSI bus. If the UCC5628 detects a HVD
SCSI device, it switches to a high impedance state.
The Multimode terminator contains all functions required to terminate and
auto detect and switch modes for SPI-2 bus architectures. Single Ended
and Differential impedances and currents are trimmed for maximum effec-
tiveness. Fail Safe biasing is provided to insure signal integrity. Device/Bus
type detection circuitry is integrated into the terminator to provide automatic
switching of termination between single ended and LVD SCSI and a high
impedance for HVD SCSI. The multimode function provides all the per-
formance analog functions necessary to implement SPI-2 termination in a
single monolithic device.
The UCC5628 is offered in a 48 pin LQFP package for a temperature
range of 0°C to 70°C.
2.15V
DIFFB 34
0.6V
HPD
(NOISE LOAD)
–15mA ≤I_SOURCE ≤–5mA
50µA ≤I_SINK ≤200µA
REF
1.3V
1.3V
35 DIFFSEN
27 LVD
26 SE
REF
2.7V
REF
1.25V
10µA
SOURCE/SINK REGULATOR
MODE
SE
LVD
DISCNCT
ALL SWITCHES
UP
DOWN
OPEN
110
124
56mV
–+
56mV
+–
52.5
52.5
SE GND SWITCH
110
12 L1–
11 L1+
DISCNCT 36
TRMPWR 3
25
GND
HS/GND
4-9
HS/GND
28-33
124
56mV
–+
56mV
+–
52.5
52.5
SE GND SWITCH
10
REG
4.7µF .
2 L14–
1 L14+
UDG-98099
SLUS302A - SEPTEMBER 1999