Microsemi

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 1

Copyright

© 2002

Rev. 1.1, 2006-02-27

LX5251

9-Line Multimode SCSI Terminator

TM

®

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.

IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com

KEY FEATUR ES

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

PRODUCT H I GHLIGHT

L X 5251

L X 5251

+

-

+

-

PACKAGE ORDER INFO

PW

Plastic TSSOP

24-Pin

RoHS Compliant / Pb-free

Transition DC: 0442

0 to 70

LX5251CPW

Note: Available in Tape & Reel.Append the letters “TR” to the

part number. (i.e. LX5251CPW-TR)