UltraMAX
T
H E
TM
LX5248/LX5249
D
A T A
9 - L
I N E
LV D S C S I T
E R M I N A T O R
I
N F I N I T E
P
O W E R
O F
I
N N O VA T I O N
P
R E L I M I N A R Y
S
H E E T
DESCRIPTION
The LX5248/49 IC is a Low Voltage Dif-
ferential (LVD) Terminator
designed to
comply with the LVD termination specifica-
tion in the SPI-2 document. The LX5248/
49 is designed specifically for LVD applica-
tions. Because the LX5248/49 supports only
LVD, it has lower output capacitance than
multimode terminators such as the LX5240.
The LX5248/49 Utilizes Linfinity’s
UltraMAX Technology
which delivers the
ultimate in SCSI bus performance while
saving component cost and board area.
Elimination of the external capacitors also
mitigates the need for a lengthy capacitor
selection process. The individual high band-
width drivers also maximize channel sepa-
ration and reduces channel-to-channel noise
and cross talk. The high-bandwidth
UltraMAX architecture insures ULTRA-2 per-
formance, while providing a clear migration
path to ULTRA-3 and beyond.
When The LX5248/49 Is Enabled, The
Differential Sense (DIFFSENSE) Pin Sup-
plies A Voltage Between 1.2V And 1.4V.
In application, the terminator DIFFSENSE
output is connected to the system
DIFFSENSE line. If there are no single ended
or HVD devices attached to the system the
LVD output will be enabled. If the
DIFFSENSE line is LOW, indicating a single
ended device, the LX5248/49 output will be
HiZ. If the DIFFSENSE line is HIGH, indi-
cating a high voltage differential device the
LX5248/49 output will be HiZ.
The LX5248/49 IC Has A TTL Compat-
ible DISCONNECT Pin.
The LX5248/49 is
active LOW. During sleep mode, power
dissipation is reduced to a meager 5µA, while
also placing all outputs in a HI Z state. Also
during sleep mode, the DIFFSENSE function
is disabled and is placed in a HI Z state.
K E Y F E AT U R E S
s
2.5pF Typical Disabled Output
Capacitance
s
Fast Response, No External Capacitors
Required
s
5µA Supply Current In Disconnect Mode
s
20mA Supply Current During Normal
Operation
s
Logic Command Disconnects All
Termination Lines
s
Diffsense Line Driver
s
Current Limit And Thermal Protection
s
Compatible With The Pending SPI-2 LVD
Specification
s
Pin Compatible With Industry Standard
Multi-Mode Terminators
s
For UCC5240 Pin Compatible LVD ONLY
Terminator (See LX5245/5246)
NOTE:
For current data & package dimensions, visit our web site:
http://www.linfinity.com.
PRODUCT HIGHLIGHT
B
U S
V
O LTA G E /
V
OD
V
OD
= V
(-)
- V
(+)
, Logic = 0
V
(+)
100mV
0V
NEGATED
V
CM
V
(-)
-100mV
LX5248/49
LX5248/49
PA C K A G E O R D E R I N F O R M AT I O N
T
A
(°C)
0 to 70K
DB
Plastic SSOP
36-pin
LX5249CDBK
PW
Plastic TSSOP
24-pin
LX5249CPWK
PW
Plastic TSSOP
28-pin
LX5248CPW
Note: All surface-mount packages are available in Tape & Reel.
Append the letter "T" to part number. (i.e. LX5249CPWT)
Copyright © 2001
Rev. 0.6 10/00
L
IN
F
INITY
M
ICROELECTRONICS
I
NC
.
11861 W
ESTERN
A
VENUE
, G
ARDEN
G
ROVE
, CA. 92841, 714-898-8121, F
AX
: 714-893-2570
1
PRODUCT DATABOOK 1996/1997
LX5248/LX5249
9 - L
I N E
LV D S C S I T
E R M I N A T O R
P
R E L I M I N A R Y
UltraMAX
D
A T A
S
H E E T
PACKAGE PIN OUTS
N.C.
N.C.
N.C.
1+
1-
2+
2-
HEATSINK/GND
HEATSINK/GND
HEATSINK/GND
3+
3-
4+
4-
5+
5-
DISCONNECT
GND
1
2
3
4
5
6
7
8
9
10/
11/
12/
13/
14/
15/
16/
17/
18/
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
A B S O L U T E M A X I M U M R AT I N G S
(Note 1)
TermPwr Voltage .............................................................................................. +6.5V
Signal Line Voltage ................................................................................... 0V to 6.5V
Differential Voltage ................................................................................... 0V to 6.5V
Operating Junction Temperature
Plastic (PW Package) ................................................................................... 150°C
Storage Temperature Range .............................................................. -65°C to 150°C
Lead Temperature (Soldering, 10 seconds) .................................................... 300°C
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 M A L D ATA
DB PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
PW PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
100°C/W
50°C/W
V
TERM
HVD
LVD
SE
9-
9+
8-
8+
HEATSINK/GND
HEATSINK/GND
HEATSINK/GND
7-
7+
6-
6+
DIFF B
DIFFSENSE
MASTER/SLAVE
Junction Temperature Calculation: T
J
= T
A
+ (P
D
x
θ
JA
).
The
θ
JA
numbers are guidelines for the thermal performance of the device/pc-board
system. All of the above assume no ambient airflow.
LX5249C
("N.C." = No Internal Connection)
DB PACKAGE
(Top View)
1+
1-
2+
2-
3+
3-
4+
4-
5+
5-
DISCONNECT
GND
1
2
3
4
5
6
7
8
9
10/
11/
12/
24
23
22
21
20
19
18
17
16
15
14
13
MASTER / SLAVE F
UNCTION
T
ABLE
MASTER /
SLAVE
L*
H
Open (Pull-up)
DIFFSENSE
Status
HI Z
1.3V
1.3V
Output
Current
0mA
15mA Source
15mA Source
V
TERM
N.C.
9-
9+
8-
8+
7-
7+
6-
6+
DIFFSENSE
MASTER/SLAVE
* When in Low state, terminator will detect state of DIFFSENSE line.
LX5249CPW
("N.C." = No Internal Connection)
PW PACKAGE
(Top View)
N.C.
1+
1-
2+
2-
N.C.
3+
3-
4+
4-
5+
5-
DISCONNECT
GND
1
2
3
4
5
6
7
8
9
10/
11/
12/
13/
14/
28
27
26
25
24
23
22
21
20
19
18
17
16
15
DIFFSENSE / P
OWER
U
P
/ P
OWER
D
OWN
F
UNCTION
T
ABLE
LX5248/LX5249
DISCONNECT
L
L
L
H
Open
DIFFSENSE
L < 0.5V
0.7V to 1.9V
H > 2.4V
X
X
Outputs
Status
Type
Disable
Enable
Disable
Disable
Disable
HiZ
LVD
HiZ
HiZ
HiZ
Quiescent
Current
2mA
21mA
2mA
10µA
10µA
V
TERM
LVD
9-
9+
8-
8+
N.C.
7-
7+
6-
6+
DIFFB
DIFFSENSE
MASTER/SLAVE
LX5248CPW
("N.C." = No Internal Connection)
PW PACKAGE
(Top View)
2
Copyright © 2001
Rev. 0.6 1/01
PRODUCT DATABOOK 1996/1997
UltraMAX
9 - L
I N E
LV D S C S I T
E R M I N A T O R
P
R E L I M I N A R Y
LX5248/LX5249
D
A T A
S
H E E T
(Note 2)
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
Termpwr Voltage
Signal Line Voltage
Disconnect Input Voltage
Operating Junction Temperature Range
LX5248 / LX5249
Note 2. Range over which the device is functional.
Symbol
V
TERM
Recommended Operating Conditions
Min.
Typ.
Max.
3.0
0
0
0
5.25
5.0
V
TERM
70
Units
V
V
V
°C
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over the operating ambient temperature range of 0°C
≤
T
A
≤
70°C. TermPwr = 3.3V,
DISCONNECT: LX5248/49 = L. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient
temperature.)
Parameter
LVD Terminator Section
TermPwr Supply Current
Common Mode Voltage
Offset Voltage (Fail Safe Bias Voltage)
Differential Terminator Impedance
Common Mode Impedance
Output Capacitance
Output Leakage
Mode Change Delay
Symbol
Test Conditions
LX5248 / 5249
Min. Typ.
Max.
21
5
1.25
112
105
200
2.5
0
1
150
1.3
25
10
1.375
125
110
300
2
Units
LVD I
CC
V
CM
V
FSB
Z
D
Z
CM
C
O
I
LEAK
t
DF
V
DIFF
I
DIFF
I
SINK (DIFF)
I
SINK (DIFF)
V
TH
I
IL
V
TH (MS)
I
IL (MS)
All term lines = Open
DISCONNECT: LX5248/49 = H
Open circuit between - and + (see Note 3)
V
OD
= -1V to 1V
0V to 2.5V
DISCONNECT: LX5248/49 = H
DISCONNECT: LX5248/49 = H, V
LINE
= 0 to 4V, T
A
=25°C
DISCONNECT: LX5248/49 = H, V
TERM
= 0V, V
LINE
= 2.7V
DIFFSENSE = 1.4V to 0V
1.125
100
100
100
100
1.2
5.0
mA
µA
V
mV
Ω
Ω
pF
µA
µA
ms
V
mA
µA
µA
V
µA
V
µA
DIFFSENSE Section
DIFFSENSE Output Voltage
DIFFSENSE Output Source Current
DIFFSENSE Sink Current
DIFFSENSE Output Leakage
DIFFSENSE = 0V
V
IN
= 2.75V
DISCONNECT: LX5248/49 = H, T
A
= 25°C
1.4
15.0
200
10
2.0
10
2.0
10
DISCONNECT Section
DISCONNECT Threshold
Input Current
0.8
DISCONNECT: LX5248/49 = 0V
0.8
MASTER / SLAVE: LX5248/49 = 0V
MASTER / SLAVE Section
MASTER / SLAVE Threshold
Input Current
Note 3. Open circuit failsafe voltage.
Copyright © 2001
Rev. 0.6 1/01
3
PRODUCT DATABOOK 1996/1997
LX5248/LX5249
9 - L
I N E
LV D S C S I T
E R M I N A T O R
P
R E L I M I N A R Y
UltraMAX
D
A T A
S
H E E T
BLOCK DIAGRAM
Power ON
V
TERMPWR
Internal V
REF
1.30V
1.07mA
1 of 9
HVD
LVD
ZD(-)
52.5
SE
LVD (-)
LVD
1.25V
Zcm
200
ZD(+)
52.5
HVD
LVD
LVD (+)
M/S
10mA
SE
DIFFSENSE
1.07mA
HVD
LATCH
LVD
DIFF B
Window
Comp.
SE
HVD
LVD
SE
Power ON
Power ON
& Mode
Change
Delay
FIGURE 1
— LX5248 / 5249 Block Diagram
4
Copyright © 2001
Rev. 0.6 1/01
PRODUCT DATABOOK 1996/1997
UltraMAX
9 - L
I N E
LV D S C S I T
E R M I N A T O R
P
R E L I M I N A R Y
LX5248/LX5249
D
A T A
S
H E E T
FUNCTIONAL PIN DESCRIPTION
Pin
Designator
1-, 2-, 3-, 4-, 5-, 6-, 8-, 8-, 9-/
V
TERM
Description
Negative signal termination lines.
Power supply pin for terminator. Connect to SCSI bus TERMPWR. Must be decoupled by one 4.7µF
low-ESR capacitor for every three terminator devices. It is absolutely necessary to connect this pin to
the decoupling capacitor through a very low impedence (big traces on PCB). Keeping distances
very short from the decoupling capacitors to the V
TERM
pin is also critical. The value of the
decoupling capacitor is somewhat layout dependant and some applications may benefit from high-
frequency decoupling with 0.1µF capacitors right at V
TERM
pin.
Enables / disables terminator. See Power Down Function Table for logic level per device.
Terminator ground pin. Connect to ground.
Sometimes referred to as M/S pin in this data sheet. Used to select which terminator is the control-
ling device. MASTER/SLAVE pin High or Open enables the DIFFSENSE output drive. Please see
MASTER/SLAVE Function Table.
This is a dual function pin. It drives the SCSI bus DIFFSENS line. It is also the sense pin to detect the
SCSI bus mode (LVD, SE or HVD). DIFFSENSE output drive can be disabled with Low level on the
MASTER/SLAVE pin. Please see DIFFSENSE and MASTER/SLAVE Function Tables. Internally
connected to DIFFB pin through 20kOhm resistor.
Internally connected to DIFFSENSE pin through 20kOhm resistor. It can be used as a mode sense
pin when the device is a non-controlling terminator (MASTER/SLAVE pin is Low). An RC filter
(20kOhm / 0.1µF) is not required on the LX5249, as it has an internal timer.
Single-ended output; when High, terminator is operating in SE mode.
Low Voltage Differential output. When High, terminator is operating in LVD mode.
High Voltage Differential output. When High, terminator is operating in HVD mode.
Attached to die mounting pad, but not bonded to GND pin. Pins should be considered a heat sink
only, and not a true groung connection. It is recommended that these pins be connected to ground,
but can be left floating.
1+, 2+, 3+, 4+, 5+, 6+, 7+, 8+, 9+/ Positive signal termination lines.
DISCONNECT/
GND/
MASTER / SLAVE/
DIFFSENSE/
DIFFB/
SE/
LVD/
HVD/
HEATSINK/
Copyright © 2001
Rev. 0.6 1/01
5
