Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

UCC5672 Datasheet(PDF) 6 Page - Texas Instruments

Click here to check the latest version.
Part No. UCC5672
Description  Multimode LVD/SE SCSI 9 Line Terminator
Download  6 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  TI [Texas Instruments]
Homepage  http://www.ti.com
Logo 

UCC5672 Datasheet(HTML) 6 Page - Texas Instruments

   
Zoom Inzoom in Zoom Outzoom out
 6 / 6 page
background image
6
UCC5672
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX (603) 424-3460
with allowance for the 3.3V supply tolerance (+/- 10%), a
unidirectional fusing device and cable drop. In 3.3V
TRMPWR systems, the UCC3918 is recommended in
place of the fuse and diode. The UCC3918's lower volt-
age drop allows additional margin over the fuse and di-
ode, for the far end terminator.
Layout is critical for Ultra2 and Ultra3/Ultra160 systems.
The SPI-2 standard for capacitance loading is 10pF max-
imum from each positive and negative signal line to
ground, and a maximum of 5pF between the positive and
negative signal lines of each pair is allowed. These maxi-
mum capacitances apply to differential bus termination
circuitry that is not part of a SCSI device, (e.g. a cable
terminator). If the termination circuitry is included as part
of a SCSI device, (e.g., a host adaptor, disk or tape
drive), then the corresponding requirements are 30pF
maximum from each positive and negative signal line to
ground and 15pF maximum between the positive and
negative signal lines of each pair.
The SPI-2 standard for capacitance balance of each pair
and balance between pairs is more stringent. The stan-
dard is 0.75pF maximum difference from the positive and
negative signal lines of each pair to ground. An additional
requirement is a maximum difference of 2pF when com-
paring pair to pair. These requirements apply to differen-
tial bus termination circuitry that is not part of a SCSI
device. If the termination circuitry is included as part of a
device, then the corresponding balance requirements are
2.25pF maximum difference within a pair, and 3pF from
pair to pair.
Feed-throughs,
through-hole
connections,
and
etch
lengths
need
to
be
carefully
balanced.
Standard
multi-layer power and ground plane spacing add about
1pF to each plane. Each feed-through will add about
2.5pF to 3.5pF. Enlarging the clearance holes on both
power and ground planes will reduce the capacitance.
Similarly, opening up the power and ground planes under
the
connector
will
reduce
the
capacitance
for
through-hole connector applications. Capacitance
will
also be affected by components, in close proximity,
above and below the circuit board.
Unitrode multi-mode terminators are designed with very
tight balance, typically 0.1pF between pins in a pair and
0.3pF between pairs. At each L+ pin, a ground driver
drives the pin to ground, while in single ended mode. The
ground driver is specially designed to not effect the ca-
pacitive balance of the bus when the device is in LVD
SCSI or disconnect mode.
Multi-layer boards need to adhere to the 120
Ω imped-
ance standard, including the connectors and feed-
throughs. This is normally done on the outer layers with
4 mil etch and 4 mil spacing between runs within a pair,
and a minimum of 8 mil spacing to the adjacent pairs to
reduce crosstalk. Microstrip technology is normally too
low of impedance and should not be used. It is designed
for 50
Ω rather than 120Ω differential systems. Careful
consideration must be given to the issue of heat manage-
ment. A multi-mode terminator, operating in SE mode,
will dissipate as much as 130mW of instantaneous power
per active line with TRMPWR = 5.25V. The UCC5672 is
offered in a 28 pin TSSOP. This package includes two
heat sink ground pins. These heat sink/ground pins are
directly connected to the die mount paddle under the die
and conduct heat from the die to reduce the junction tem-
perature. Both of the HS/GND pins need to be connected
to etch area or four feed-through per pin connecting to
the ground plane layer on a multi-layer board.
APPLICATION INFORMATION (cont.)


Html Pages

1  2  3  4  5  6 


Datasheet Download



Related Electronics Part Number

Part NumberComponents DescriptionHtml ViewManufacturer
UCC5673Multimode LVD/SE SCSI 9 Line Terminator 1 2 3 4 5 MoreTexas Instruments
UCC5628Multimode SCSI 14 Line Terminator 1 2 3 4 5 Texas Instruments
UCC5629Multimode SCSI 14 Line Terminator 1 2 3 4 5 Texas Instruments
UCC5630AMultimode SCSI 9 Line Terminator 1 2 3 4 5 MoreTexas Instruments
UCC5631AMultimode SCSI 9 Line Terminator 1 2 3 4 5 MoreTexas Instruments
UCC5638Multimode SCSI 15 Line Terminator 1 2 3 4 5 Texas Instruments
UCC5639Multimode SCSI 15 Line Terminator with Reverse Disconnect 1 2 3 4 5 MoreTexas Instruments
UCC5641Low Voltage Differential LVD SCSI 9 Line Terminator 1 2 3 4 Texas Instruments
UCC569627 LINE LVD ONLY SCSI TERMINATOR FOR SPI-5 1 2 3 4 5 MoreTexas Instruments
LX5226ULTRA 1 8 - LINE SCSI TERMINATOR 1 2 3 4 Microsemi Corporation

Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Alldatasheet API   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn