LX5250 View Datasheet(PDF) - Microsemi Corporation

Part Name

Description

MFG CO.

LX5250

9-Line Multimode SCSI Terminator

Microsemi Corporation 

LX5250/5252

TM

®

9-Line Multimode SCSI Terminator

PRODUCTION DATA SHEET

PIN NAME

1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-

FUNCTIONAL PIN DESCRIPTION

DESCRIPTION

Negative signal termination lines for LVD mode. Signal termination lines for SE mode.

1+, 2+, 3+, 4+, 5+, 6+, 7+, 8+, 9+ Positive signal termination lines for LVD mode. Psuedo-ground lines for SE mode.

VTERM

DISCONNECT

Power supply pin for terminator. Connect to SCSI bus VTERM. Must be

decoupled by one 4.7µF low-ESR capacitor for every three terminator devices. It is

absolutely necessary to connect this pin to the decoupling capacitor through a very low

impedance (big traces to PCB). Keeping distances very short from the decoupling

capacitors is somewhat layout dependent and some applications may benefit from high

frequency decoupling with 0.1µF capacitors at VTERM pin.

Enables/Disables terminator. See Power Down Function Table for logic levels

for LX5250 and LX5252.

GND

MASTER/SLAVE

DIFFSENSE

DIFFB

SE

Terminator ground pin. Connect to ground.

Sometimes referred to as M/S pin in this datasheet. Used to select which terminator is the

controlling device. M/S pin High or Open enables the DIFFSENSE output drive. Please

see MASTER/SLAVE Function Table.

This is a dual function pin. It drives the SCSI bus DIFFSENS line. It is also the sense pin

to detect the SCSI bus mode (LVD, SE, or HVD). DIFFSENSE output drive can be

disabled with low level on the M/S pin. Please see DIFFSENSE and MASTER/SLAVE

Function Tables. Internally connected to DIFFB pin through a 20K Ω resistor.

Internally connected to DIFFSENSE pin through a 20K Ω resistor. It can be used as a

mode sense pin when the device is non-controlling terminator (M/S is low). An RC filter

(50K Ω resistor & 4.7µF) is not required on the LX5250 as it has an internal timer.

Single-Ended output; when High, terminator is operating in SE mode.

LVD

Low Voltage Differential output; when High, terminator is operating in LVD mode.

HVD

HEATSINK

High Voltage Differential output; when High, terminator is operating in HVD mode.

Attached to die mounting pad, but not bonded to GND pin. Pins should be considered a

heat sink only, and not a true ground connection. It is recommended that these pins be

connected to ground, but can be left floating.

Copyright © 2002

Rev. 1.2b, 2005-08-29

Microsemi

Integrated Products Division

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

Page 5

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