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LX5115A

ULTRA 9 - CHANNEL SCSI TERMINATOR

Microsemi Corporation 

LX5115A

PRODUCT DATABOOK 1996/1997

ULTRA 9-CHANNEL SCSI TERMINATOR

PRODUCTION DATA SHEET

TERM POWER

BLOCK DIAGRAM

CURRENT

BIASING

CIRCUIT

24mA CURRENT

LIMITING CIRCUIT

UltraMAX

DATA OUTPUT

PIN DB(0)

DISABLE

PIN

2.0V

2.85V

1 OF 9 CHANNELS

FUNCTIONAL DESCRIPTION

Cable transmission theory suggests to optimize signal speed by delivering 24mA on assertion and by imposing 2.85V on

and quality, the termination should act both as an ideal voltage deassertion. In order to disable the device, the Disable pin

reference when the line is released (deasserted) and as an must be driven logic Low. This mode of operation places

ideal current source when the line is active (asserted). Common the device in a sleep state where a meager 200µA of quiescent

active terminators, which consist of

current is consumed. Additionally, all

Linear Regulators in series with resis- POWER UP / POWER DOWN FUNCTION TABLE outputs are in a Hi-Z (impedance)

tors (typically 110Ω), are a compro-

state. Sleep mode can be used for

mise. As the line voltage increases,

the amount of current decreases lin-

Disable

LX5115A

Outputs

Quiescent

Current

power conservation or to completely

eliminate the terminator from the SCSI

early by the equation V = I * R. The

LX5115A, with its unique new archi-

H

Enabled

5.5mA

chain. In the second case, termination

node capacitance is important to

tecture applies the maximum amount

L

HI Z

200µA

consider. The terminator will appear

of current regardless of line voltage

Open

Enabled

5.5mA

as a parasitic distributed capacitance

until the termination high threshold

on the line, which can detract from bus

(2.85V) is reached.

performance. For this reason, the

Acting as a near ideal line terminator, the LX5115A closely LX5115A has been optimized to have only 3pF of capacitance

reproduces the optimum case when the device is enabled. per output in the sleep state.

To enable the device the Disable Pin must be pulled Logic

An additional feature of the LX5115A is its compatibility with

High or left open. During this mode of operation, quiescent active negation drivers. The device handles up to 7mA of sink

current is 5.5mA and the device will respond to line demands current for drivers which exceed the 2.85V output high.

UltraMAX is a trademark of Linfinity Microelectronics Inc.

PRODUCTION DATA - Information contained in this document is proprietary to LinFinity, and is current as of publication date. This document

may not be modified in any way without the express written consent of LinFinity. Product processing does not necessarily include testing of

all parameters. Linfinity reserves the right to change the configuration and performance of the product and to discontinue product at any time.

4

Copyright © 2000

Rev. 1.0 4/00

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