UCC5630A_09 Datasheet, PDF (1/12 Pages) Texas Instruments – Multimode SCSI 9 Line Terminator

UCC5630A
Multimode SCSI 9 Line Terminator
FEATURES
• Auto Selection Single Ended (SE) or
Low Voltage Differential (LVD)
Termination
• Meets SCSI-1, SCSI-2, Ultra2 (SPI-2
LVD), Ultra3, Ultra160 (SPI-3) and
Ultra320 (SPI-4) Standards
• 2.7V to 5.25V Operation
• Differential Failsafe Bias
• Thermal packaging for low junction
temperature and better MTBF
• Master/Slave Input
• Supports Active Negation
• 3pF Channel Capacitance
BLOCK DIAGRAM
DESCRIPTION
The UCC5630A Multimode SCSI Terminator provides a smooth transition
into the LVD SCSI Parallel Interface (SPI-2, SPI-3, SPI-4). It automatically
senses the bus, via DIFFB, and switches the termination to either single
ended (SE) or low voltage differential (LVD) SCSI, dependent on which
type of devices are connected to the bus. The UCC5630A can not be used
on a HVD, EIA485, differential SCSI bus. If the UCC5630A 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, SPI-3 and SPI-4 bus architectures.
Single Ended and Differential impedances and currents are trimmed for
maximum effectiveness. Fail Safe biasing is provided to insure signal integ-
rity. 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 pro-
vides all the performance analog functions necessary to implement SPI-2
termination in a single monolithic device.
The UCC5630A is offered in a 36 pin SSOP package, as well as a 48 pin
LQFP package for a temperature range of 0°C to 70°C.
DIFFB 21
MSTR/SLV ¹⁹
2.15V
HIPD LVD SE
35 34 33
0.6V
SE REF 2.7V
SOURCE/SINK REGULATOR
LVD REF 1.25V
10µA
DISCNCT 17
TRMPWR 36
ENABLE
SWITCHES
MODE
ALL
SWITCHES
SE
UP
LVD
DOWN
HIPD
OPEN
DISCNCT OPEN
HIPD
LVD
SE
(NOISE LOAD)
REF 1.3V
1.3V
20 DIFSENS
–15mA ≤ I_SOURCE ≤ –5mA
50µA ≤ I_SINK ≤ 200µA
110
124
56mV
–+
56mV
+–
52.5
52.5
SE GND SWITCH
110
5 L1–
4 L1+
124
56mV
–+
56mV
+–
52.5
52.5
SE GND SWITCH
32 L9–
31 L9+
18
GND
8 9 10 26 27 28
HS/GND
1
REG
Note: Indicated pinout is for 36 pin SSOP package.
SLUS322C - SEPTEMBER 1999 - REVISED MARCH 2002
PATENTED CIRCUIT DESIGN
UDG-98192