/ .
SLUS348A – MARCH 1997 – REVISED NOVEMBER 2000
Complies with SPI-2 and SPI-3 Standards
2.75-V to 7-V Operation
1.8-pF Channel Capacitance during
Disconnect
1-µA Supply Current in Disconnect Mode
110-Ω/2.5-k Programmable Termination
Completely Meets SCSI Hot Plugging
–650-mA Sourcing Current for Termination
+400-mA Sinking Current for Active
Negation Drivers
Trimmed Termination Current to 4%
Trimmed Impedance to 7%
Current Limit and Thermal Shutdown
Protection
description
The UCC5611 provides 18 lines of active termination for a SCSI (Small Computer Systems Interface) parallel
bus. The SCSI standard recommends active termination at both ends of the cable segment.
The UCC5611 is ideal for high performance 3.3-V SCSI systems. The key features contributing to such
low-operating voltage are the 0.1-V drop-out regulator and the 2.75-V reference. During disconnect the supply
current is typically only 1 µA, which makes the IC attractive for battery powered systems.
The UCC5611 is designed with an ultra-low channel capacitance of 1.8 pF, which eliminates effects on signal
integrity from disconnected terminators at interim points on the bus.
The UCC5611 can be programmed for either a 110-Ω or 2.5-kΩ termination. The 110-Ω termination is used for
standard SCSI bus lengths and the 2.5-kΩ termination is typically used in short bus applications. When driving
the TTL compatible DISCNCT pin directly, the 110-Ω termination is connected when the DISCNCT pin is driven
high, and disconnected when low. When the DISCNCT pin is driven through an impedance between 80 kΩ and
150 kΩ, the 2.5-kΩ termination is connected when the DISCNCT pin is driven high, and disconnected when
driven low.
block diagram
UDG-94131-1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright 2000, Texas Instruments Incorporated
!$%'#)!%$ !( *''$) ( % &*"!)!%$ )
'%*)( %$%'# )% (&!!)!%$( &' ) )'#( % ,( $()'*#$)(
()$' +''$)- '%*)!%$ &'%((!$ %( $%) $(('!"- !$"*
)()!$ % "" &'#)'(
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SLUS348A – MARCH 1997 – REVISED NOVEMBER 2000
description (continued)
The power amplifier output stage allows the UCC5611 to source full termination current and sink active negation
current when all termination lines are actively negated.
The UCC5611 is pin for pin compatible with Texas Instrument’s other 18-line SCSI terminators, except that
DISCNCT is now active low, allowing lower capacitance and lower voltage upgrades to existing systems. The
UCC5611, as with all of Texas Instrument terminators, is completely hot pluggable and appears as high
impedance at the terminating channels with VTRMPWR = 0 V or open.
Internal circuit trimming is utilized, first to trim the 110-Ω termination impedance to a 7% tolerance, and then most
importantly, to trim the output current to a 4% tolerance, which maximizes noise margin.
Other features include thermal shutdown and current limit.
This device is offered in low thermal resistance versions of the industry standard 28-pin wide body SOIC and
28-pin PLCC.
DWP PACKAGE
TOP VIEW
28
27
26
25
24
23
22
21
20
19
18
17
16
15
LINE11
LINE10
REG
TRMPWR
LINE9
LINE8
LINE7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
GND
LINE18
LINE17
LINE16
LINE15
LINE14
GND*
GND*
GND*
LINE13
LINE12
LINE11
LINE10
REG
LINE12
LINE13
LINE14
LINE15
LINE16
LINE17
LINE18
5
4
3 2 1 28 27 26
25
6
24
7
23
8
22
9
21
10
20
11
19
12 13 14 15 16 17 18
* DWP package pin 28 serves as signal ground;
pins 7, 8, 9, 20, 21, 22 serve as heatsink/ground.
* QP package pins 12-18 serve as both heatsink
and signal ground.
AVAILABLE OPTIONS
PACKAGED DEVICES
TJ
0°C to 70°C
SOIC (DWP)
PLCC (QP)
UCC5611DWP
UCC5611QP
† Available tape and reeled. Add TR suffix to device type to order quantities of 1000 devices per reel.
2
LINE6
LINE5
LINE4
LINE3
LINE2
LINE1
DISCNCT
GND*
GND*
GND*
GND*
GND*
GND*
GND*
DISCNCT
LINE1
LINE2
LINE3
LINE4
LINE5
GND*
GND*
GND*
LINE6
LINE7
LINE8
LINE9
TRMPWR
QP PACKAGE
TOP VIEW
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SLUS348A – MARCH 1997 – REVISED NOVEMBER 2000
absolute maximum ratings over operating free-air temperature (unless otherwise noted)†
Termpwr voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Signal line voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to 7 V
Regulator output current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Self-regulating
Storage temperature, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C
Operating junction temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to 150°C
Lead temperature (soldering, 10 Sec.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300°C
† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
‡ Unless otherwise specified all voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal. Consult
Packaging Section of Interface Products Data Book (TI Literature Number SLUD002) for thermal limitations and considerations of packages.
recommended operating conditions
Termpwr voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.75 V to 5.25 V
Signal line voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to 5 V
Disconnect input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to Termpwr
electrical characteristics, these specifications apply for TA = 0°C to 70°C. TRMPWR = 3.3 V,
DISCNCT = 3.3 V, RDISCNCT = 0 Ω. TA = TJ, (unless otherwise stated)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Supply Current Section
Termpwr supply current
Power down mode
All termination lines = open
1
2
mA
All termination lines = 0.2 V
415
435
mA
DISCNCT = 0V
0.5
5
µA
110
117.7
Ω
Output Section (110 Ω – Terminator Lines)
Terminator impedance
See Note 4
Output high voltage
TRMPWR = 3 V,
See Note 1
VLINE = 0.2 V,
VLINE = 0.2 V
TJ = 25°C
VLINE = 0.2 V,
See Note 1
TRMPWR = 3 V,
VLINE = 0.2 V,
VLINE = 0.5 V
TRMPWR = 3 V,
Output leakage
DISCNCT = 0 V,
TRMPWR = 0 V to 5.25 V
Output capacitance
DISCNCT = 0 V,
See Note 3
DWP package,
Max output current
102.3
2.5
2.7
3.0
–25.4
–23
–22.1
mA
–25.4
–23
–21
mA
TJ = 25°C,
–25.4
–23
–20.2
mA
See Note 1
–25.4
–23
See Note 2,
V
–19
mA
–22.4
mA
10
400
nA
1.8
2.5
pF
Output Section (2.5 kΩ – Terminator Lines) (RDISCNCT = 80 kΩ)
Terminator impedance
Output high voltage
TRMPWR = 3 V,
See Note 1
Max output current
VLINE = 0.2 V
VLINE = 0.2 V,
TRMPWR = 3 V,
Output leakage
DISCNCT = 0 V,
TRMPWR = 0 to 5.25 V
Output capacitance
DISCNCT = 0 V,
See Note 3
DWP package,
NOTES: 1.
2.
3.
4.
See Note 1
See Note 2,
2
2.5
3
kΩ
2.5
2.7
3.0
V
–1.4
–1
–0.7
mA
–1.5
–1
–0.6
mA
10
400
nA
1.8
2.5
pF
Measuring each termination line while other 17 are low (0.2 V).
Ensured by design. Not production tested.
Output capacitance is measured at 0.5 V.
Tested by measuring IOUT with VOUT = 0.2 V and VOUT = VREG – 0.1 V then calculating the impedance.
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3
SLUS348A – MARCH 1997 – REVISED NOVEMBER 2000
electrical characteristics, these specifications apply for TA = 0°C to 70°C. TRMPWR = 3.3 V,
DISCNCT = 3.3 V, RDISCNCT = 0 Ω. TA = TJ, (unless otherwise stated)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
2.5
2.7
3.0
0.1
0.2
–800
–650
–450
mA
200
400
800
mA
Regulator Section
Regulator output voltage
5.25 V > TRMPWR > 3 V
V
Drop out voltage
All termination lines = 0.2 V
Short circuit current
Sinking current capability
VREG = 0 V
VREG = 3 V
Thermal shutdown
See Note 2
170
°C
Thermal shutdown hysteresis
See Note 2
10
°C
V
Disconnect Section
Disconnect threshold
RDISCNCT = 0 & 80 kΩ
Input current
DISCNCT = 3.3 V
0.8
1.5
2.0
V
30
50
µA
NOTES: 2. Ensured by design. Not production tested.
APPLICATION INFORMATION
UDG-94132
Figure 1. Typical SCSI Bus Configurations Utilizing a UCC5611 Device
4
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Copyright 2000, Texas Instruments Incorporated