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LIN DOC #:
5121
T HE I NFINITE P OWER OF I NNOVATION
DESCRIPTION KEY FEATURES
The LX5121 Plug and Play UltraMAXTM terminator represents next-generation technology
for SCSI termination applications. The lowvoltage BiCMOS architecture employed in its
design offers superior performance to older
passive and active techniques.
Linfinity's architecture employs high-speed
adaptive elements for each channel, providing
the fastest response possible. The channel
bandwidth is typically 35MHz. The LX5121
compares favorably to older linear regulator
approaches whose bandwidth's are dominated by the output compensation capacitor
and are limited to the 500KHz bandwidth
region (see further discussion in the Functional
Description section). Linfinity's architecture
also eliminates the output compensation
capacitor typical in earlier terminator designs.
Each is approved for use with SCSI-1,-2,-3,
ULTRA and beyond — providing the highest
performance alternative available today.
Another key improvement of LX5121 products lies in their ability to ensure reliable, errorfree communications even in systems which
do not necessarily adhere to recommended
SCSI hardware design guidelines, such as the
use of improper cable lengths and imped-
ances. Frequently, this situation is not controlled by the peripheral or host designer and,
when problems occur, they are the first to
be made aware of these problems. The
LX5121 architecture is much more tolerant of
marginal system integrations.
Recognizing the needs of portable and
configurable peripherals, the LX5121 has a
TTL compatible sleep/disable mode. Typically, quiescent current is less than 150µA in
this mode.
Reduced component count is also inherent
in the LX5121 architecture. Traditional termination techniques require large stabilization and transient protection capacitors of up
to 20µF in value and size. The LX5121
architecture does not require these components, allowing all the cost savings associated
with inventory, board space, assembly, reliability, and component costs.
The LX5121 has multiple disables for full
Plug and Play SCSI capability for Host Bus
Adapters with 3 SCSI connectors. It also splits
the upper 9 termination lines for mixing 16bit (wide) and 8-bit (narrow) buses with
minimal board trace capacitance.
TM
UltraMAX
LX5121
ULTRA 27-LINE, PLUG AND PLAY SCSI TERMINATOR
P RODUCTION DATA SHEET
■ Ultra-Fast Response For Fast-20 SCSI
Applications
■ Plug And Play SCSI For Host Bus
Adapters With 3 SCSI Connectors
■ Split Disconnect For Mixing 16-Bit
(Wide) Or 8-Bit (Narrow) Buses
■ 35mhz Channel Bandwidth
■ Sleep-Mode Current Less Than 150µA
■ Hot-Swap Compatible
■ NO External Compensation Capacitors
■ Compatible With Active Negation
Drivers
■ Superior Pin-for-Pin Replacement For
The UCC5621
NOTE: For current data & package dimensions, visit our web site: http://www.linfinity.com.
PRODUCT HIGHLIGHT
DRIVING WAVEFORM - 20MHZRECEIVING WAVEFORM - 20MHZ
Receiver
1 Meter, AWG 28
LX5121 LX5121
LX5268 LX5268
PACKAGE ORDER INFO
(°C)
T
J
0 to 125 LX5121CDB
Append the letter "T" to part number. (i.e. LX5121CDBT)
Note: Available in Tape & Reel.
Plastic SSOP
DB
44-pin
Driver
NOTE:
For An In-Depth
Discussion On Applying
SCSI, Request Linfinity
Application Note:
"Understanding The
Single-Ended SCSI Bus"
Copyright © 1999
Rev. 1.0 5/99
L INF INITY MICROELECTRONICS INC.
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
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PRODUCT DATABOOK 1996/1997
LX5121
ULTRA 27-LINE, PLUG AND PLAY SCSI TERMINATOR
RODUCTION DATA SHEET
P
ABSOLUTE MAXIMUM RATINGS (Note 1)
TermPwr Voltage .....................................................................................................7V
Continuous Output Voltage Range .............................................................. 0 to 5.5V
Continuous Disable Voltage Range .............................................................. 0 to 5.5V
Operating Junction Temperature
Plastic (DB Packages) .................................................................................... 150ºC
Storage Temperature Range ............................................................. -65°C to +150°C
Solder Temperature (Soldering, 10 seconds) ................................................... 300°C
Note 1. Exceeding these ratings could cause damage to the device.
THERMAL DATA
DB PACKAGE:
D
x θ
θθ
θ
θθ
JA
).
JA
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
Junction Temperature Calculation: TJ = TA + (P
The θ
numbers are guidelines for the thermal performance of the device/pc-board
JA
system. All of the above assume no ambient airflow.
50°C/W
UltraMAX
PACKAGE PIN OUTS
T19
T20
W1
W2
GND
GND
GND
GND
DISC1
DISC2
T10
T21
T22
144
243
342
T1
441
T2
540
639
738
T3
837
T4
936
T5
10 35
11 34
12 33
13 32
14 31
15 30
16 29
T6
17 28
T7
18 27
T8
19 26
T9
20 25
21 24
22 23
T27
T26
T25
T18
N1
T17
T16
T15
N.C.
GND
GND
GND
GND
V
T
T14
T13
T12
N.C.
N.C.
T11
T24
T23
DB PACKAGE
(Top View)
RECOMMENDED OPERATING CONDITIONS (Note 2)
Parameter
Termination Voltage V
High Level Disable Input Voltage V
Low Level Disable Input Voltage V
Operating Virtual Junction Temperature Range
LX5121C
Note 2. Range over which the device is functional.
Symbol
TERM
IH
IL
Recommended Operating Conditions
Min. Typ. Max.
Units
4.0 5.5 V
2V
TERM
V
0 0.8 V
0 125 °C
ELECTRICAL CHARACTERISTICS
Term Power = 4.75V unless otherwise specified. Unless otherwise specified, these specifications apply at the recommended operating ambient temperature of TA = 25°C. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient temperature.
Parameter
Output High Voltage V
TermPwr Supply Current I
Symbol
OUT
CC
Test Conditions Units
All data lines = open
All data lines = 0.2V
Disable Pins 1 & 2 < 0.8V
Output Current I
Disable Input Current DISC1 I
OUTVOUT
IN
= 0.2V
DISC1 = 0V
DISC2 DISC2 = 0V
Output Leakage Current DISC1 and DISC2= < 0.8V, VO = 0.2V
Channel Bandwidth BW
Termination Sink Current, per Channel I
SINKVOUT
= 4V
LX5121
Min. Typ. Max.
2.65 2.85 V
12 20 mA
635 670 mA
50 150 µ A
-20 -22 -24 mA
-10 µA
-10 µA
1µA
35 MHz
7mA
2
Copyright © 1999
Rev. 1.0 5/99
Page 3
PRODUCT DATABOOK 1996/1997
UltraMAX
V
V
CC
CC
DISC1
DISC2
1.4V
ULTRA 27-LINE, PLUG AND PLAY SCSI TERMINATOR
P RODUCTION DATA SHEET
BLOCK DIAGRAM
TERM POWER
CURRENT
BIASING
CIRCUIT
24mA CURRENT
LIMITING CIRCUIT
LX5121
DATA OUTPUT
PIN DB(0)
2.85V
1 OF 27 CHANNELS
FUNCTIONAL DESCRIPTION
Cable transmission
theory suggests that in
order to optimize signal speed and quality,
the termination
should act both as an
ideal voltage reference when the line is
released (de-asserted)
and as an ideal current
source when the line
is active (asserted).
Common active terminators, which consist
of Linear Regulators in
series with resistors
(typically 110Ω), are a
compromise. As the
line voltage increases, the amount of current decreases linearly
by the equation V = I * R. The UltraMAX LX5121, with its
unique new architecture, applies the maximum amount of
current regardless of line voltage until the termination high
threshold (2.85V) is reached.
Acting as a near ideal line terminator, the LX5121 closely
DISC1 DISC2 W1 W2 N1 T1-T18 T19-T27
H L DC DC DC Enabled
L H DC DC DC
L L DC DC DC
H H H H H Enabled Enabled
H H H H L Enabled Enabled
H H H L H Enabled Enabled
HHHLL
H H L H H Enabled Enabled
HHLHL
HHLLH
H H LLL
POWER UP / POWER DOWN FUNCTION TABLE
reproduces the optimum case when the
device is enabled. To
Disabled
Disabled
Enabled
Disabled Disabled
Disabled
Disabled
Enabled
Enabled
Disabled Disabled
Disabled Disabled
escent current is consumed. Additionally, all outputs are in
a Hi-Z (impedance) state. Sleep mode can be used for power
conservation or to completely eliminate the terminator from
the SCSI chain.
An additional feature of the LX5121 is its compatibility with
active negation drivers.
enable the device the
DISC1 and DISC2 pins
must be driven per the
above table. During
this mode of operation,
quiescent current is
12mA and the device
will respond to line demands by delivering
24mA on assertion and
by imposing 2.85V on
de-assertion. Disable
mode places the device
in a sleep state, where
a meager 150µA of qui-
Copyright © 1999
Rev. 1.0 5/99
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PRODUCT DATABOOK 1996/1997
LX5121
ULTRA 27-LINE, PLUG AND PLAY SCSI TERMINATOR
RODUCTION DATA SHEET
P
PLUG AND PLAY SCSI DIAGRAM
Internal Narrow
Internal Wide
LX5121
UltraMAX
External
Wide
For Plug and Play SCSI auto-termination diabling, connect pin 50 of the External Wide SCSI connector to W1 of the LX5121,
connect pin 50 of the Internal Wide SCSI connector to W2 of the LX5121, and connect pin 22 of the Internal Narrow connector
to N1 of the LX5121.
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.
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UltraMAX is a trademark of Linfinity Microelectronics Inc.
Copyright © 1999
Rev. 1.0 5/99
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