UCC5617_15 [TI]
18-Line SCSI Terminator (Reverse Disconnect);
| 型号： | UCC5617_15 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 18-Line SCSI Terminator (Reverse Disconnect) |
| 文件： | 总5页 (文件大小：316K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
UCC5617
18-Line SCSI Terminator (Reverse Disconnect)
FEATURES
DESCRIPTION
•
•
•
Complies with SCSI, SCSI-2,
SCSI-3 and FAST-20 Standards
The UCC5617 provides 18 lines of active termination for a SCSI (Small
Computers Systems Interface) parallel bus. The SCSI standard recommends
and Fast-20 (Ultra) requires active termination at both ends of the cable.
2pF Channel Capacitance
During Disconnect
Pin for pin compatible with the UC5609, the UCC5617 is ideal for high perfor-
mance 5V SCSI systems, Termpwr 4.0V to 5.25V. During disconnect the sup-
ply current is only 50µA typical, which makes the IC attractive for lower pow-
ered systems.
50µA Supply Current in
Disconnect Mode
•
•
110Ω Termination
The UCC5617 is designed with a low channel capacitance of 2pF, which elim-
inates effects on signal integrity from disconnected terminators at interim
points on the bus.
SCSI Hot Plugging Compliant,
10nA Typical
The power amplifier output stage allows the UCC5617 to source full termina-
tion current and sink active negation current when all termination lines are
actively negated.
•
+400mA Sinking Current for
Active Negation
•
•
−650mA Sourcing Current for
The UCC5617, as with all Unitrode terminators, is completely hot pluggable
and appears as high impedance at the terminating channels with
TRMPWR=0V or open.
Termination
Trimmed Impedance to 5%
Internal circuit trimming is utilized, first to trim the 110Ω impedance, and then
most importantly, to trim the output current as close to the maximum SCSI-3
specification as possible, which maximizes noise margin in fast SCSI opera-
tion.
Other features include thermal shutdown and current limit.
This device is offered in low thermal resistance versions of the industry stan-
dard 28 pin wide body SOIC, TSSOP and PLCC.
BLOCK DIAGRAM
UDG-96073
Circuit Design Patented
4/97
UCC5617
ABSOLUTE MAXIMUM RATINGS
Tempwr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+7V
Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0V to +7V
Regulator Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1A
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .−65°C to +150°C
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . .−55°C to +150°C
Lead Temperature (Soldering, 10 Seconds) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .300°C
All currents are positive into, negative out of the specified terminal. Consult Packaging
Section of Databook for thermal limitations and considerations of packages.
CONNECTION DIAGRAMS
PLCC-28 (Top View)
QP Package
TSSOP-28 (Top View)
PWP Package
* DWP package pins 12 - 18 serve as both heatsink and signal
ground.
* PWP package pin 23 serves as signal ground; pins 7, 8, 9,
20, 21, and 22 serve as heatsink ground.
DIL-24 (Top View)
N Package
SOIC-28 (Top View)
DWP Package
* N package for engineering samples only.
* DWP package pin 28 serves as signal ground; pins 7, 8, 9,
20, 21, 22 serve as heatsink/ground.
Note: Drawings are not to scale.
2
UCC5617
ELECTRICAL CHARACTERISTICS Unless otherwise stated these specifications apply for TA = 0°C to 70°C,
TRMPWR = 4.75V, DISCNCT = 4.75V, TA = TJ.
PARAMETER
Supply Current Section
Termpwr Supply Current
TEST CONDITIONS
MIN
TYP
MAX
UNITS
All termination lines = Open
1
2
mA
mA
µA
All termination lines = 0.2V
DISCNCT = 0V
420
50
450
100
Power Down Mode
Output Section (Termination Lines)
Termination Impedance
Output High Voltage
(Note 3)
104.5
2.6
110
2.8
115.5
3
Ω
VTRMPWR = 4V (Note 1)
VLINE = 0.2V, TJ = 25°C
VLINE = 0.2V
V
Maximum Output Current
−22.1
−20.7
−23.3
−23.3
–23
−24
−24
–24
–24
−22.4
400
mA
mA
mA
mA
mA
nA
VLINE = 0.2V, TRMPWR = 4V, TJ = 25°C (Note 1) –21
VLINE = 0.2V, TRMPWR = 4V (Note 1)
–20
–23
VLINE = 0.5V
Output Leakage
DISCNCT = 0V, TRMPWR = 0V to 5.25V,
REG = 0.2V, VLINE = 5.25V
10
2
Output Capacitance
Regulator Section
DISCNCT = 2.4V (Note 2)
3.5
pF
Regulator Output Voltage
Drop Out Voltage
2.6
2.8
0.4
3
V
V
All Termination Lines = 0.2V
VREG = 0V
0.8
Short Circuit Current
Sinking Current Capability
Thermal Shutdown
–475
200
−650
400
170
10
−850
800
mA
mA
°C
°C
VREG = 3.5V
Thermal Shutdown Hysteresis
Disconnect Section
Disconnect Threshold
Input Current
0.8
1.5
2
V
DISCNCT = 0V
−10
−30
µA
Note 1: Measuring each termination line while other 17 are low (0.2V).
Note 2: Guaranteed by design. Not 100% tested in production.
Note 3:Tested by measuring IOUT with VOUT = 0.2V and VOUT with no load, then calculating:
VOUT N.L. – 0.2V
IOUT at 0.2V
Z =
.
Procedure:
1) Measure VREG N.L.
2) Set VL = 0.2V; Measure IMAX at 0.2V
VREG N.L. – 0.2V
IMAX at 0.2V
3) Impedance =
UDG-97108
Figure 1.Termline Impedance Measurement Circuit
3
UCC5617
PIN DESCRIPTIONS
DISCNCT: Taking this pin low causes the 18 channels to LINE 1-18: 110Ω termination channels.
become high impedance and the chip to go into low-power
mode; a high or open state allows the channels to provide
normal termination.
REG: Output of the internal 2.8V regulator.
TRMPWR: Power for the IC.
GND: Ground reference for the IC.
APPLICATION INFORMATION
UDG-96074
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX (603) 424-3460
4
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