LX5255
TM
®
9-Line LVD SCSI Terminator
P
RODUCTION
DATA SHEET
BLOCK DIAGRAM
WWW .
Microsemi
.C
OM
VTERM
24
DISC
1.07 mA
1 of 9
Lines
HVD
LVD
SE
DISC
13
3
LVD(-)
52.5
150
HVD
52.5
1.25V
1.07 mA
LVD
SE
10mA
I-Limited
1.3V
Source
DIFSENS
DIFFB
2
LVD(+)
12
DISC
-
+
SE
HVD
LATCH
Window
Comp.
GND
11
10
LVD
POWER
ON
&
MODE
DELAY
Figure 1 –
LX5255CPW Block Diagram
FUNCTIONAL PIN DESCRIPTION
P
IN
N
AME
1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-
1+, 2+, 3+, 4+, 5+, 6+, 7+, 8+, 9+
D
ESCRIPTION
Negative signal termination lines for LVD mode.
Positive signal termination lines for LVD mode.
Power supply pin for terminator. Connect to SCSI bus VTERM. Must be
decoupled by one 4.7
µ
F low-ESR capacitor for every three terminator devices. It is
V
TERM
absolutely necessary to connect this pin to the decoupling capacitor through a very low
impedance (big traces to PCB). Keeping distances very short from the decoupling
capacitors is somewhat layout dependent and some applications may benefit from high
frequency decoupling with 0.1
µ
F capacitors at V
TERM
pin.
P
ACKAGE
D
ATA
P
ACKAGE
D
ATA
DISC
GND
DIFSENS
DIFFB
5
Enables/Disables terminator. See Power Down Function Table for logic levels
.
Terminator ground pin. Connect to ground.
Differential sense pin connected to system DIFFSENS line. Drives the SCSI bus
DIFSENS line to 1.3V.
Used to detect the SCSI bus mode (SE, LVD or HVD). Should be connected to a 4.7uF
capacitor to GND, and a 50KΩ resistor to the DIFFSENS pin (see Figure 2 on page 5).
Copyright
©
2000
Rev. 1.1, 2006-02-27
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
MICROSEMI [ MICROSEMI CORPORATION ]
