MICROSEMI LX5226CDWPT

LIN D O C #: 5226
UltraMAX
TM
LX5226
U LT R A 1 8 - L I N E S C S I T E R M I N A T O R
T
H E
I
N F I N I T E
P
O W E R
O F
I
P
N N O VA T I O N
R O D U C T I O N
D
DESCRIPTION
The LX5226 SCSI terminator is part of
Linfinity's UltraMAX family of high-performance, adaptive, non-linear mode SCSI
products, which are designed to deliver true
UltraSCSI performance in SCSI applications.
The low-voltage BiCMOS architecture employed in its design offers superior performance to older linear passive and active
techniques.
Linfinity's UltraMAX architecture employs
high-speed adaptive elements for each channel, thereby providing the fastest response
possible — typically 35MHz, which is 100
times faster than the older linear regulator/
terminator approach used by other manufacturers. Products using this older linear
regulator approach have bandwidths which
are dominated by the output capacitor and
which are limited to 500KHz (see further
discussion in the Functional Description
section). The UltraMAX architecture also
eliminates the output compensation capacitor typical in earlier terminator designs. Each
is approved for use with SCSI-1, -2, -3,
UltraSCSI and beyond — providing the highest performance alternative available today.
The LX5226 architecture is much more
tolerant of marginal system integrations. A
A T A
S
H E E T
K E Y F E AT U R E S
key improvement offered by the LX5226 lies
in its ability to ensure reliable, error-free
communications even in systems which do
not adhere to recommended SCSI hardware
design guidelines, such as the use of improper cable lengths and impedances. 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 the problem.
To enter the disconnect mode, the disconnect pin must be driven high, thereby disconnecting the LX5226 from the SCSI bus.
Quiescent current is less than 150µA in this
mode.
Reduced component counts is also inherent in the LX5226 architecture. Traditional
termination techniques require large stabilization and transient protection capacitors
of up to 20µF in value and size. The LX5226
architecture does not require these components, allowing all the cost savings associated
with inventory, board space, assembly, reliability, and component costs.
The LX5226 is a superior pin-for-pin replacement for the LX5207, the UC5601 / 5602
/ 5610 and the UCC5610.
■ Ultra-Fast Response For Fast-20 SCSI
Applications
■ 35MHz Channel Bandwidth
■ Sleep-Mode Current Less Than 150µA
■ NO External Compensation Capacitors
■ Compatible With Active Negation Drivers
■ Compatible With Passive And Active
Terminations
■ Approved For Use With SCSI 1, 2, 3 And
Ultra SCSI
■ Hot-Swap Compatible
■ Pin-For-Pin Compatible With LX5207,
UC5601/5602 And UCC5610
NOTE: For current data & package dimensions, visit our web site: http://www.linfinity.com.
PRODUCT HIGHLIGHT
R E C E I V I N G W AV E F O R M - 2 0 M H Z
D R I V I N G W AV E F O R M - 2 0 M H Z
Driver
Receiver
1 Meter, AWG 28
DISC
LX5226
LX5226
LX5268
LX5268
PA C K A G E O R D E R I N F O
TA (°C)
0 to 70
SOWB
DWP Plastic
28-pin, Power
LX5226CDWP
Note: All surface-mount packages are available in Tape & Reel.
Append the letter "T" to part number. (i.e. LX5226CDWPT)
Copyright © 1999
Rev. 1.0 5/99
DISC
NOTE:
For An In-Depth
Discussion On Applying
SCSI, Request Linfinity
Application Note:
"Understanding The
Single-Ended SCSI Bus"
LINFINITY MICROELECTRONICS INC.
11861 W ESTERN A VENUE, G ARDEN G ROVE, CA. 92841, 714-898-8121, F AX: 714-893-2570
1
PRODUCT DATABOOK 1996/1997
UltraMAX
LX5226
U LT R A 1 8 - L I N E S C S I T E R M I N A T O R
P
R O D U C T I O N
A B S O L U T E M A X I M U M R AT I N G S
D
A T A
S
H E E T
PACKAGE PIN OUTS
(Note 1)
TermPwr Voltage ................................................................................................. +7V
Signal Line Voltage ................................................................................... 0V to +7V
Operating Junction Temperature
Plastic (DWP Packages) ............................................................................... 150°C
Storage Temperature Range .............................................................. -65°C to 150°C
Lead Temperature (Soldering, 10 seconds) .................................................... 300°C
DISC
T1
T2
T3
T4
T5
HEAT SINK/GND
GND
HEAT SINK/GND
T6
T7
T8
T9
VTERM
Note 1. Exceeding these ratings could cause damage to the device. All voltages are with
respect to Ground. Currents are positive into, negative out of the specified
terminal.
T H E R MAL DATA
DWP PACKAGE:
THERMAL RESISTANCE-JUNCTION TO LEADS, θJL
18°C/W
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ JA
40°C/W
1
28
2
27
3
26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
GND
T18
T17
T16
T15
T14
HEAT SINK/GND
HEAT SINK/GND
HEAT SINK/GND
T13
T12
T11
T10
N.C.
DWP PACKAGE
(Top View)
Junction Temperature Calculation: TJ = TA + (PD x θJA).
The θ JA numbers are guidelines for the thermal performance of the device/pc-board
system. All of the above assume no ambient airflow.
R E C O M M E N D E D O P E R AT I N G C O N D I T I O N S
Parameter
Symbol
Termpwr Voltage
Signal Line Voltage
Disconnect Input Voltage
Operating Virtual Junction Temperature Range
LX5226C
VTERM
(Note 2)
Recommended Operating Conditions
Min.
Typ.
Max.
Units
4.0
0
0
5.5
5
VTERM
V
V
V
0
125
°C
Note 2. Range over which the device is functional.
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
2
Symbol
Output High Voltage
TermPwr Supply Current
VOUT
ICC
Output Current
Disconnect Input Current
Output Leakage Current
Channel Bandwidth
Termination Sink Current, per Channel
IOUT
IIN
IOL
BW
ISINK
Test Conditions
Min.
2.65
All data lines = open
All data lines = 0.2V
DISC Pin > 2.0V
VOUT = 0.2V
DISC Pin = 0V
DISC Pin = > 2.0V, VO = 0.2V
-20
LX5226
Typ.
Max.
2.85
10
424
50
-22
35
VOUT = 4V
7
15
450
150
-24
-10
1
Units
V
mA
mA
µA
mA
µA
µA
MHz
mA
Copyright © 1999
Rev. 1.0 5/99
PRODUCT DATABOOK 1996/1997
UltraMAX
LX5226
U LT R A 1 8 - L I N E S C S I T E R M I N A T O R
P
R O D U C T I O N
D
A T A
S
H E E T
BLOCK DIAGRAM
FIGURE 1 — LX5226 BLOCK DIAGRAM
TERM POWER
CURRENT
BIASING
CIRCUIT
24mA CURRENT
LIMITING CIRCUIT
DATA OUTPUT
PIN DB(0)
2.85V
DISC
1.4V
1 OF 18 CHANNELS
A P P L I C AT I O N S C H E M AT I C
FIGURE 2 — 8-BIT SCSI SYSTEM APPLICATION
PERIPHERAL
TERM POWER
DB (0)
DB (1)
DB (0)
DB (1)
ACK
RST
MSG
ACK
RST
MSG
LX5226
5V
4.7µF
DISC
LX5226
VTERM
~ ~
VTERM
~ ~ ~
4.7µF
DISC
HOST
TERM POWER
5V
SCSI CABLE
Copyright © 1999
Rev. 1.0 5/99
3
PRODUCT DATABOOK 1996/1997
UltraMAX
LX5226
U LT R A 1 8 - L I N E S C S I T E R M I N A T O R
P
R O D U C T I O N
D
A T A
S
H E E T
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 (deasserted)
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 LX5226, 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 LX5226 closely
reproduces the optimum case when the device is enabled.
To enable the device a DISC pin must be pulled Logic Low.
During this mode of operation, quiescent current is 6mA and
the device will respond to line demands by delivering 24mA
on assertion and by imposing 2.85V on deassertion. In order
to disable the device, the DISC pin must be driven logic High.
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 power conservation or to completely eliminate the
terminator from the SCSI chain.
An additional feature of the LX5226 is its compatibility with
active negation drivers.
POWER UP / POWER DOWN FUNCTION TABLE
DISC Pin
Outputs
Quiescent
Current
L
H
Open
Enabled
HI Z
HI Z
15mA
150µA
150µA
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 © 1999
Rev. 1.0 5/99