lx5225 Microsemi Corporation, lx5225 Datasheet - Page 4

• Manufacturer Part Number: lx5225
• Description: Ultra 18-line, Plug And Play Scsi Terminator
• Manufacturer: Microsemi Corporation

LX5225
4
Cable transmission theory suggests to optimize signal speed
and quality, the termination should act both as an ideal voltage
reference when the line is released (deasserted) and as an
ideal current source when the line is active (asserted). Common
active terminators, which
consist of Linear Regula-
tors in series with resis-
tors (typically 110 ), are
a compromise.
line voltage increases,
the amount of current de-
creases linearly by the
equation V = I * R. The
LX5225, with its unique
new architecture applies
the maximum amount of
current regardless of line voltage until the termination high
threshold (2.85V) is reached.
reproduces the optimum case when the device is enabled.
Acting as a near ideal line terminator, the LX5225 closely
As the
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.
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
U
DISC 1
Open
LT R A
H
H
L
L
P
18-L
P
R O D U C T I O N
OWER
F U N C T I O N A L D E S C R I P T I O N
UltraMAX is a trademark of Linfinity Microelectronics Inc.
I N E
U
, P
P
DISC 2
Open
/ P
H
H
L
L
L U G A N D
OWER
D
OWN
D
P
To enable the device a DISC1 and DISC2 pins must be pulled
Logic High. During this mode of operation, quiescent current
is 10mA and the device will respond to line demands by
delivering 24mA on assertion and by imposing 2.85V on
power conservation or to completely eliminate the terminator
from the SCSI chain.
active negation drivers.
L AY
A T A
Outputs
Disabled
Disabled
Disabled
Enabled
Enabled
An additional feature of the LX5225 is its compatibility with
F
UNCTION
SCSI T
S
H E E T
T
E R M I N AT O R
ABLE
Quiescent
Current
150µA
150µA
15mA
15mA
15mA
deassertion.
disable the device, the
DISC1 and DISC2 pins
must be driven logic Low.
This mode of operation
places the device in a sleep
state where a meager
150µA of quiescent current
is consumed. Additionally,
all outputs are in a Hi-Z
(impedance) state. Sleep
mode can be used for
UltraMAX
In order to
Copyright © 1999
Rev. 1.0
5/99