LX5251
TM
®
9-Line Multimode SCSI Terminator
P
RODUCTION
DATA SHEET
DESCRIPTION
The LX5251 is a multimode SCSI
terminator that is compatible with the
SCSI SPI-2 (Ultra2), SCSI SPI-3 (Ultra3
or Ultra160), and SCSI SPI-4 (Ultra320)
specifications developed by the T10
standards committee for low voltage
differential (LVD) termination, while
providing backwards compatibility to the
SCSI, SCSI-2, and SPI single-ended
specifications. Multimode compatibility
permits the use of legacy devices on the
bus without hardware alterations.
Automatic mode selection is achieved
through voltage detection on the
Diffsense line.
The LX5251 utilizes an industry
standard
LVD
architecture.
The
individual high bandwidth drivers
maximize channel separation, reduce
channel-to-channel noise and cross talk
to insure Ultra320 performance.
When the LX5251 is enabled, the
differential sense (DIFFSENSE) pin
supplies a voltage between 1.2V and
1.4V. In
application, this pin is tied to the DIFFSENSE
input of the corresponding LVD transceivers.
This action enables the LVD transceiver
function. DIFFSENSE is capable of supplying
a maximum of 15mA.
Tying the DIFFSENSE pin high places the
LX5251 in a HI-Z state indicating the presence
of an HVD device. Tying the pin low places
the part in a single-ended mode while also
signaling the multimode transceiver to operate
in a single-ended mode.
Recognizing the needs of portable and
configurable peripherals, the LX5251 has a
TTL compatible sleep/disable mode. During
this sleep/disable mode, power dissipation is
reduced to a meager 15uA while also placing
all outputs in a HI-Z state. Also during
sleep/disable mode, the DIFFSENSE function
is disabled and is placed in a HI-Z state.
The LX5251 also provides a master / slave
function. Driving this pin high or floating the
pin enables the 1.3V DIFFSENSE reference.
Driving the pin low disables the on board
DIFFSENSE reference and enables use of an
external master reference device.
KEY FEATURES
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Microsemi
.C
OM
Compliant with SCSI SPI-2
(Ultra2), SPI-3 (Ultra160), and
SPI-4 (Ultra320)
Auto-Selectable LVD or Single-
Ended Termination
Fast Response, No Output
Capacitors Required
Compatible with Active Negation
Drivers
15µA Supply Current in
Disconnect Mode
Logic Command Disconnects All
Termination Lines
Diffsense Line Driver
Ground Driver Integrated for
Single-Ended Operation
Current Limit and Thermal
Protection
Hot-Swap Compatible (Single-
Ended)
Available in 24-pin TSSOP
Package
IMPORTANT:
For the most current data, consult
MICROSEMI’s
website:
http://www.microsemi.com
PRODUCT HIGHLIGHT
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+
L X 5251
+
L X 5251
LX5251
LX5251
PACKAGE ORDER INFO
Plastic TSSOP
PW
24-Pin
T
A
(°C)
0 to 70
LX5251CPW
RoHS Compliant / Pb-free
Transition DC: 0442
Note: Available in Tape & Reel.Append the letters “TR” to the
part number. (i.e. LX5251CPW-TR)
Copyright
©
2002
Rev. 1.1, 2006-02-27
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
MICROSEMI [ MICROSEMI CORPORATION ]
