UCC5629FQPG4 [TI]
MULTIMODE SCSI 14 LINE TERMINATOR;
| 型号： | UCC5629FQPG4 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | MULTIMODE SCSI 14 LINE TERMINATOR 信息通信管理 接口集成电路 |
| 文件： | 总5页 (文件大小：57K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
UCC5629
Multimode SCSI 14 Line Terminator
DESCRIPTION
FEATURES
The UCC5629 Multimode SCSI Terminator provides a smooth transition
into the next generation of the SCSI Parallel Interface (SPI-2). It automati-
cally senses the bus, via DIFFB, and switches the termination to either sin-
gle ended (SE) or low voltage differential (LVD) SCSI, dependent on which
type of devices are connected to the bus. The UCC5629 can not be used
on a HVD, EIA485, differential SCSI bus. If the UCC5629 detects a HVD
SCSI device, it switches to a high impedance state.
• Auto Selection Single Ended (SE) or
Low Voltage Differential (LVD)
Termination
• Meets SCSI-1, SCSI-2, SCSI-3, SPI,
Ultra (Fast-20), Ultra2 (SPI-2 LVD)
and Ultra3 Standards
• 2.7V to 5.25V Operation
• Differential Failsafe Bias
The Multimode terminator contains all functions required to terminate and
auto detect and switch modes for SPI-2 bus architectures. Single Ended
and Differential impedances and currents are trimmed for maximum effec-
tiveness. Fail Safe biasing is provided to insure signal integrity. Device/Bus
type detection circuitry is integrated into the terminator to provide automatic
switching of termination between single ended and LVD SCSI and a high
impedance for HVD SCSI. The multimode function provides all the perform-
ance analog functions necessary to implement SPI-2 termination in a sin-
gle monolithic device.
• Thermal packaging for low junction
temperature and better MTBF.
• Reversed Polarity Disconnect
The UCC5629 is offered in a 48 pin LQFP package for a temperature range
of 0°C to 70°C.
BLOCK DIAGRAM
(NOISE LOAD)
1.3V
HPD
REF
1.3V
–15mA ≤ I
≤ –5mA
≤ 200µA
SOURCE
35 DIFFSEN
27 LVD
50µA ≤ I
SINK
2.15V
DIFFB 34
0.6V
SE
26
110
124
REF
2.7V
SOURCE/SINK REGULATOR
56mV
52.5
52.5
REF
1.25V
– +
12 L1–
56mV
+
–
L1+
11
MODE
SE
ALL SWITCHES
UP
LVD
DISCNCT
DOWN
OPEN
SE GND SWITCH
56mV
10µA
110
124
DISCNCT
TRMPWR
36
3
52.5
52.5
–
+
2
1
L14–
L14+
56mV
+
–
SE GND SWITCH
HS/GND
4-9
HS/GND
28-33
25
10
REG
4.7µF .
GND
UDG-99156
SLUS444 - NOVEMBER 1999
UCC5629
CONNECTION DIAGRAMS
ABSOLUTE MAXIMUM RATINGS
TRMPWR Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +6V
Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . 0V to TRMPWR
Package Dissipation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2W
Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C
Junction Temperature. . . . . . . . . . . . . . . . . . . –55°C to +150°C
Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300°C
Recommended Operating Conditions . . . . . . . . . 2.7V to 5.25V
(TOP VIEW)
FQP Package
HS/GND
HS/GND
HS/GND
HS/GND
HS/GND
HS/GND
REG
L1+
L1–
TRMPWR
L14–
L14+
Currents are positive into negative out of the specified terminal.
Note: Consult Packaging Section of Databook for thermal limi-
tations and considerations of package.
12
10
2
11
9
8
7
6
4
3
1
5
L2+
L2–
L3+
L3–
L4+
L4–
L5+
L5–
L6+
L6–
L7+
L7–
L13–
L13+
L12–
L12+
L11–
L11+
L10–
L10+
L9–
13
14
15
48
47
46
45
44
43
42
41
40
39
38
37
16
17
RECOMMENDED OPERATING CONDITIONS
TRMPWR Voltage . . . . . . . . . . . . . . . . . . . . . . . . 2.7V to 5.25V
Temperature Ranges . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C
18
19
20
21
22
23
24
L9+
L8–
L8+
25
27
35
26
28 29 30 31
33 34
36
32
DISCNCT
DIFFSENS
DIFFB
GND
SE
LVD
HS/GND
HS/GND
HS/GND
HS/GND
HS/GND
HS/GND
ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for TA = TJ = 0°C to 70°C,
TRMPWR = 3.3V.
PARAMETER
TRMPWR Supply Current Section
TRMPWR Supply Current
TEST CONDITIONS
MIN
TYP
MAX UNITS
LVD Mode
SE Mode
20
1.6
250
25
10
mA
mA
A
Disabled Terminator
400
Regulator Section
1.25V Regulator
LVD Mode
VREG= 0V
VREG= 3.3V
Diff Sense
VREG= 0V
VREG= 3.3V
SE Mode
1.15
1.25
1.35
V
1.25V Regulator Source Current
1.25V Regulator Sink Current
1.3V Regulator
–375 –700 –1000 mA
170
1.2
–15
50
300
1.3
700
1.4
–5
mA
V
1.3V Regulator Source Current
1.3V Regulator Sink Current
2.7V Regulator
mA
A
200
3.0
2.5
2.7
V
2.7V Regulator Source Current
2.7V Regulator Sink Current
Differential Termination Section
Differential Impedance
Common Mode Impedence
Differential Bias Voltage
Common Mode Bias
VREG= 0V
VREG= 3.3V
–375 –700 –1000 mA
170
300
700
mA
100
110
100
1.15
105
150
110
165
125
1.35
3
(Note 2)
mV
V
1.25
Output Capacitance
Single Ended Measurement to Ground (Note 1)
2
pF
UCC5629
ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for TA = TJ = 0°C to 70°C,
TRMPWR = 3.3V.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNITS
Single Ended Termination Section
Impedance
102.3
110
117.7
(VLX −0.2V )
Z =
, (Note 3)
ILX
Termination Current
Signal Level 0.2V, All Lines Low
Signal Level 0.5V
–21
–18
–24
–25.4
–22.4
400
3
mA
mA
nA
Output Leakage
Output Capacitance
Single Ended Measurement to Ground (Note 1)
I= 10mA
pF
Single Ended GND SE Impedance
Disconnect and Diff Buffer Input Section
DISCNCT Threshold
20
10
60
0.8
2.0
30
V
A
V
V
A
DISCNCT Input Current
Diff Buffer Single Ended to LVD Threshold
Diff Buffer LVD to HPD Threshold
DIFFB Input Current
0.5
1.9
–10
0.7
2.4
10
Status Bits (SE, LVD) Output Section
ISOURCE
VLOAD = 2.4V
VLOAD = 0.4V
–4
2
–6
5
mA
mA
ISINK
Note 1: Guaranteed by design. Not 100% tested in production.
1.2V
Note 2: ZCM
=
where VCM=voltage measured with L+ tied to L– and zero current applied
I
[
(VCM +0.6V ) – I(VCM −0.6V )
]
Note 3: VLX= Output voltage for each terminator minus output pin (L1– through L14–) with each pin unloaded.
ILX = Output current for each terminator minus output pin (L1– through L14–) with the minus output pin forced to 0.2V.
PIN DESCRIPTIONS
DIFFB: Diff sense filter pin should be connected at a LVD: TTL Compatible status bit indicating that the device
has detected the bus in LVD mode. If the terminator is
connected it is in LVD mode.
0.1 F capacitor.
DIFFSENS: The SCSI bus Diff Sense line to detect what
REG: Regulator bypass pin, must be connected to a
types of devices are connected to the SCSI bus.
F capacitor.
DISCNCT: Disconnect pin shuts down the terminator
when it is not at the end of the bus. The disconnect pin
high enables the terminator.
SE: TTL Compatible status bit indicating that the device
has detected the bus in single ended mode. If the termi-
nator is connected it is in single ended mode.
LINEn–: Signal line active line for single ended or nega-
tive line in differential applications for the SCSI bus.
TRMPWR: VIN 2.7V to 5.25V supply.
LINEn+: Ground line for single ended or positive line for
differential applications for the SCSI bus.
3
UCC5629
APPLICATION INFORMATION
The ucc5629 is a Multi-mode active terminator with se- and 4 mil spacing between the runs within a pair, and a
lectable single ended (SE) and low voltage differential minimum of 8 mil spacing to the next pair. This spacing
(LVD) SCSI termination integrated into a monolithic com- between the pairs reduces potential crosstalk. Beware of
ponent. Mode selection is accomplished with the “diff feed-throughs and each through hole connection adds a
sense" signal.
lot of capacitance. Standard power and ground plane
spacing yields 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 can
reduce the capacitance and opening up the power and
ground planes under the connector can reduce the ca-
pacitance for through hole connector applications. Mi-
crostrip technology is normally too low of impedance and
should not be used. It is designed for 50 rather than
120 differential systems.
The diff sense signal is a three level signal, which is
driven at each end of the bus by one active terminator. A
LVD or multi-mode terminator drives the diff sense line to
1.3 V. If diff sense is at 1.3 V, then bus is in LVD mode. If
a single ended SCSI device is plugged into the bus, the
diff sense line is shorted to ground. With diff sense
shorted to ground, the terminator changes to single
ended mode to accommodate the SE device. If a HVD
device is plugged in to the bus, the diff sense line is
pulled high and the terminator shuts down.
Capacitance balance is critical for Ultra2 and Ultra3. The
balance capacitance standard is 0.5pF per line with the
balance between pairs of 2pF. The components are de-
signed with very tight balance, typically 0.1pF between
pins in a pair and 0.3pF between pairs. Layout balance is
critical, feed-throughs and etch length must be balanced,
preferably no feed-throughs would be used. Capacitance
for devices should be measured in the typical application,
material and components above and below the circuit
board effect the capacitance.
The diff sense line is driven and monitored by the termi-
nator through a 50Hz noise filter at the DIFFB input pin.
A set of comparators, that allow for ground shifts, deter-
mine the bus status as follows. Any diff sense signal be-
low 0.5V is single ended, between 0.7V and 1.9V is LVD
and above 2.2V is HVD.
In the single ended mode, a multi-mode terminator has a
110 terminating resistor connected to a 2.7V termina-
tion voltage regulator. The 2.7V regulator is used on all
Unitrode terminators designed for 3.3V systems. This re-
quires the terminator to operate in specification down to
2.7V TRMPWR voltage to allow for the 3.3V supply toler-
ance, an unidirectional fusing device and cable drop. At
each L+ pin, a ground driver drives the pin to ground,
while in single ended mode. The ground driver is spe-
cially designed so it will not effect the capacitive balance
of the bus when the device is in LVD or disconnect mode.
The device requirements call for 1.5pF balance on the
lines of a differential pair. The terminator capacitance has
to be a small part of the capacitance imbalance.
Multi-mode terminators need to consider power dissipa-
tion; the ucc5629 is offered in a power package with heat
sink ground pins. These heat sink/ground pins are di-
rectly connected to the die mount paddle under the die
and conduct heat from the die to reduce the junction
temperature. These pins need to be connected to etch
area or a feed-through per pin connecting to the ground
plane layer on a multi-layer board.
In 3.3V TRMPWR systems, the UCC3912 should be
used to replace the fuse and diode. This reduces the
voltage drop, allowing for cable drop to the far end termi-
nator. 3.3V battery systems normally have a 10% toler-
ance. The UCC3912 is 150mV drop under LVD loads,
allowing 150mV drop in the cable system. All Unitrode
LVD and multi-mode terminators are designed for 3.3V
systems, operating down to 2.7V.
Layout is very critical for Ultra2 and Ultra3 systems.
Multi-layer boards need to adhere to the 120 imped-
ance standard, including connector and feed-through.
This is normally done on the outer layers with 4 mil etch
4
UCC5629
TYPICAL APPLICATION
L1+
L1–
L1+
L1–
TERMPWR
TRMPWR
3
TRMPWR
TRMPWR
3
CONTROL LINES (9)
L9+
L9–
L9+
L9–
L10+
L10–
L10+
L10–
4 BITS OF THE HIGH BYTE
L13+
L13–
L13+
L13–
36
36
DISCNCT
DISCNCT
DIFFSENSE 35
35 DIFFSENSE
REG
10
DIFF B
34
DIFF B
34
REG
10
20k
20k
4.7µF
0.1µF
0.1µF
.
.
.
4.7µF
220k
4.7µF
4.7µF
.
L1+
L1–
L1+
L1–
DATA LINES (15)
DATA LINES (15)
LOW BYTE 8+ PARITY
L9+
L9–
L9+
L9–
3
TRMPWR
TRMPWR
3
L10+
L10–
L10+
L10–
HIGH BYTE 4 BITS
PLUS PARITY
L14+
L14–
L14+
L14–
36
36
DISCNCT
DISCNCT
REG
10
DIFF B
34
DIFF B
34
REG
10
4.7µF
.
4.7µF
SCSI CONTROLLER
DIFFSENS
UDG-99157
Note: A 220k resistor is added to ground to insure the transceivers will come up in single-ended mode when no terminator is en-
abled. The controller DIFFSENS ties to the DIFFB pin on the terminators, only one RC network should be on a device.
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX (603) 424-3460
5
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