UCC5680_15 Datasheet, PDF (1/11 Pages) Texas Instruments – 9-LINE LVD ONLY SCSI TERMINATOR

ą
D LVD-Only Active Termination
D 2.7 V to 5.25 V Operation
D Differential Failsafe Bias
D Built-In SPI-3 Mode Change Filter/Delay
UCC5680
9ĆLINE LVD ONLY SCSI TERMINATOR
WITH INTEGRATED SPIĆ3 DELAYS
SLUS313D − MARCH 1999 - REVISED NOVEMBER 2003
D Standards Supported: SPI-2, SPI-3, SPI-4,
Ultra2 (Fast 40), Ultra3/Ultra160 (Fast 80)
and Ultra320 (Fast 160)
description
The UCC5680 is an LVD-only Small Computer System Interface (SCSI) terminator that integrates the mode
change delay function required by the SPI-3 specification. The device senses what types of SCSI drivers are
present on the bus via the voltage on the DIFFSENS SCSI control line. Single-ended (SE) and high-voltage
differential (HVD) SCSI drivers (EIA485) are not supported. If the chip detects the presence of an SE or HVD
SCSI driver, it disconnects itself by switching all terminating resistors off the bus and enters a high-impedance
state. The terminator can also be commanded to disconnect the terminating resistors with the DISCNCT input.
Impedance is trimmed for accuracy and maximum effectiveness. Bus lines are biased to a failsafe state to
ensure signal integrity.
The UCC5680 is offered in both 24-pin and 28-pin TSSOP (PW) packages for a temperature range of 0°C to
70°C.
functional block diagram
2.15 V +
DIFFB 11
+
0.6 V
100 ms
TO
300 ms
DELAY/
FILTER
HIGH−VOLTAGE
DIFFERENTIAL
LOW−VOLTAGE
DIFFERENTIAL
SINGLE−ENDED
−15 mA≤ I_SOURCE≤ −5 mA
50 µA ≤ I_SINK ≤ 200 µA
REF
1.3V
27 LVD{
12 DIFSENS
DISCNCT 15
TRMPWR 28
10 µA
ENABLE
REF
1.25V
MODE ALL SWITCHES
SE
LVD
HVD
DISCNCT
OPEN
DOWN
OPEN
OPEN
14
GND
124
56 mV
−+
56 mV
+−
52
4 L1 −
52
3 L1+
1
REG
124
56 mV
−+
56 mV
+−
52
25 L9 −
52
26 L9+
{28-PIN PACKAGE ONLY
UDG−00067
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
www.ti.com
Copyright  2000, Texas Instruments Incorporated
1