MICROSEMI LX5225CDWP

LIN D O C #: 5225
UltraMAX
TM
U LT R A 18-L I N E , P L U G
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
LX5225
AND
R O D U C T I O N
DESCRIPTION
The LX5225 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 SCSI1, -2, -3, UltraSCSI and beyond — providing
the highest performance alternative available
today.
The LX5225 architecture is much more tolerant of marginal system integrations. A key
P L AY SCSI T E R M I N AT O R
D
A T A
S
H E E T
K E Y F E AT U R E S
improvement offered by the LX5225 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 pins must be driven low thereby disconnecting the LX5225 from the SCSI bus. The
LX5225 has two disconnect pins for SCSI Plug
and Play (PnP) applications. Quiescent current
is less than 150µA in this mode.
Reduced component counts is also inherent
in the LX5225 architecture. Traditional termination techniques require large stabilization
and transient protection capacitors of up to
20µF in value and size. The LX5225 architecture does not require these components, allowing all the cost savings associated with
inventory, board space, assembly, reliability,
and component costs.
The LX5225 is a superior pin-for-pin replacement for the LX5205 and the UCC5607.
■ SCSI Plug And Play, Dual Low Disconnect,
Logic Low Command Disconnects All
Termination Lines
■ 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 LX5205 And
UC5607
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
Receiver
DISC 1
DISC 2
Driver
1 Meter, AWG 28
LX5225
PnP
LX5268
LX5225
PnP
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
LX5225CDWP
Note: All surface-mount packages are available in Tape & Reel.
Append the letter "T" to part number. (i.e. LX5225CDWPT)
Copyright © 1999
Rev. 1.0 5/99
DISC 1
DISC 2
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
LX5225
U LT R A 18-L I N E , P L U G
P
AND
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
P L AY SCSI T E R M I N AT O R
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
DISC1
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
DISC2
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
LX5225C
(Note 2)
Recommended Operating Conditions
Min.
Typ.
Max.
VTERM
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
DISC1 and DISC2 Pins < 0.8V
VOUT = 0.2V
DISC1 and DISC2 Pins = 0V
DISC1 and DISC2 Pins = < 0.8V, VO = 0.2V
-20
LX5225
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
LX5225
U LT R A 18-L I N E , P L U G
P
AND
R O D U C T I O N
P L AY SCSI T E R M I N AT O R
D
A T A
S
H E E T
BLOCK DIAGRAM
FIGURE 1 — LX5225 BLOCK DIAGRAM
TERM POWER
CURRENT
BIASING
CIRCUIT
24mA CURRENT
LIMITING CIRCUIT
DATA OUTPUT
PIN DB(0)
2.85V
DISC1
DISC2
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
TERM POWER
LX5225
VTERM
DB (0)
DB (1)
DB (0)
DB (1)
ACK
RST
MSG
ACK
RST
MSG
LX5225
5V
4.7µF
PnP
DISCONNECT
VTERM
~ ~
4.7µF
PERIPHERAL
~ ~ ~
PnP
DISCONNECT
HOST
TERM POWER
5V
SCSI CABLE
Copyright © 1999
Rev. 1.0 5/99
3
PRODUCT DATABOOK 1996/1997
UltraMAX
LX5225
U LT R A 18-L I N E , P L U G
P
AND
R O D U C T I O N
P L AY SCSI T E R M I N AT O R
D
A T A
S
H E E T
FUNCTIONAL DESCRIPTION
To enable the device a DISC1 and DISC2 pins must be pulled
Cable transmission theory suggests to optimize signal speed
Logic High. During this mode of operation, quiescent current
and quality, the termination should act both as an ideal voltage
is 10mA and the device will respond to line demands by
reference when the line is released (deasserted) and as an
delivering 24mA on assertion and by imposing 2.85V on
ideal current source when the line is active (asserted). Common
deassertion. In order to
active terminators, which
POWER UP / POWER DOWN FUNCTION TABLE
disable the device, the
consist of Linear RegulaDISC1 and DISC2 pins
tors in series with resisQuiescent
DISC 1
DISC 2
Outputs
must be driven logic Low.
tors (typically 110Ω), are
Current
This mode of operation
a compromise. As the
H
H
Disabled
15mA
places the device in a sleep
line voltage increases,
state where a meager
the amount of current deH
L
Enabled
15mA
150µA of quiescent current
creases linearly by the
L
H
Enabled
15mA
is consumed. Additionally,
equation V = I * R. The
L
L
Disabled
150µA
all outputs are in a Hi-Z
LX5225, with its unique
(impedance) state. Sleep
new architecture applies
Open
Open
Disabled
150µA
mode can be used for
the maximum amount of
power conservation or to completely eliminate the terminator
current regardless of line voltage until the termination high
from the SCSI chain.
threshold (2.85V) is reached.
An additional feature of the LX5225 is its compatibility with
Acting as a near ideal line terminator, the LX5225 closely
active negation drivers.
reproduces the optimum case when the device is enabled.
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