.
SLUS213B – APRIL 1998 – REVISED FEBRUARY 2001
SPI-2 and SPI-3 Compliant
2.85-V Regulated Output
simplified block diagram
Voltage with 1.4% Tolerance
THERMAL
SHUTDOWN
Provides Current for up to
27 Lines of Active Termination
for SCSI Buses
TRMPWR
–750-mA Sourcing Current
(See Note A)
for Termination
300-mA Sinking Current for
Active Negation Drivers
0.9-V Dropout Voltage Regulator
at 750 mA and 2.75 V Output
100- A Supply Current in
Disconnect Mode
Current Limit and Thermal Shutdown
Protection
Low Thermal Resistance Surface
Mount Package
8
1
OUT
2.85 V
2.85 V
REF
+
+
INTERNAL
BIAS
4
ENBL
2
3
6
7
GND GND GND GND
Note A: 4.0 V TO 6.0 V (4.75 V NOMIMAL)
description
The UC560 provides current for up to 27 lines of active termination for a SCSI (small computers systems
interface) parallel bus. The SCSI standard requires active termination at both ends of the cable. The UC560
is based on the UC5603 and UC5613 SCSI active terminators. It uses the voltage regulator and internal logic
circuits of those parts, but has no termination circuits. The UC560 provides greater source current-drive
capability compared to the UC5603 and UC5613.
The UC560 sink current maintains regulation with all active-negation drivers negated. It provides a disconnect
feature which disables the regulator to greatly reduce standby power. Internal circuit trimming is utilized for a
1.4% tolerance output voltage. Other features include thermal shutdown and current limit for short circuit
conditions.
The UC560 is available in low-thermal-resistance version of the industry standard 8-pin power SOIC.
AVAILABLE OPTIONS
TA
PACKAGED DEVICES
SOIC (DP)†
0°C to 70°C
UC560DP
† The DP package is available taped and reeled. Add TR suffix to device type (e.g. UC560DPTR) to order
quantities of 3000 devices per reel.
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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1
SLUS213B – APRIL 1998 – REVISED FEBRUARY 2001
DP PACKAGE
(TOP VIEW)
OUT
HS/GND
HS/GND
ENBL
1
8
2
7
3
6
4
5
TERMPWR
HS/GND
HS/GND
N/C
NOTE 1: For DP package, pins 2, 3, 6 and 7 are heat sinking pins. Pin 2 is the connect point for electrical ground.
NOTE 2: For all packages, N/C is no connection.
absolute maximum ratings over operating free-air temperature (unless otherwise noted)† ‡
Input voltage,
TERMPWR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
ENBL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to TERMPWR + 0.3 V
Regulator Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 A
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 W
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to 150°C
Lead Temperature (Soldering, 10 seconds) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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.
‡ Currents are positive into and 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
MIN
Input voltage, TERMPWR
MAX
4.0
6.0
Operating virtual junction temperature, TJ
0
70
¶ It is not recommended that the device operate under conditions beyond those specified in this table for extended periods of time.
2
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UNIT
V
°C
SLUS213B – APRIL 1998 – REVISED FEBRUARY 2001
electrical characteristics over recommended operating free-air temperature range,
TA = 0°C to 70°C, TERMPWR = 4.75 V, ENBL = 0 V, COUT = 4.7µF, CTERMPWR = 4.7 µF, TA = TJ, unless
otherwise specified.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Supply Current Section
TERMPWR supply current
Power down mode
No load
IOUT = –700 mA
ENBL = 2.0 V
18
25
mA
710
750
mA
100
140
µA
2.85
2.89
25
30
mV
10
20
mV
V
Regulator Section
Regulator output voltage
25°C, No load
Load regulation
IOUT = 300 mA to –750 mA
TERMPWR = 4.0 V to 6.0 V
See Note 1
Line regulation
Dropout voltage
Short circuit current
2.81
IOUT = –750 mA
VOUT = 0.0 V
See Note 1
No load,
VOUT = 2.75 V
V
0.9
1.2
–1.3
–0.85
500
600
mA
1
2
mA
A
Sinking current
VOUT = 3.5 V
ENBL = 2.0 V
Thermal shutdown
See Note 2
170
°C
Thermal shutdown hysteresis
See Note 2
10
°C
VOUT = 3.0 V
Shutdown Section
ENBL threshold
1.1
Threshold hysteresis
ENBL output current
NOTES:
–15
1.4
1.7
V
100
mV
–10
µA
1. Tested at a constant junction temperature by low duty cycle pulse testing.
2. Ensured by design. Not production tested.
pin descriptions
ENBL: (Enable pin) The ENBL function is active low, and the pin sources 10 µA (typical) when at ground and
TERMPWR is between 4 V and 6 V. The part goes into disable mode if ENBL is above 1.4 V (typical) , and returns
to enable mode when ENBL drops below 1.3 V typical. The part also greatly reduces TERMPWR current when
disabled (100 µA typical).
GND: Ground pin.
OUT: (2.85-V regulated output voltage pin) The part is internally current limited for both sinking and sourcing
current to prevent damage. When the part is in disabled mode (ENBL 1.4 V typical), the output goes to 0 V with
no external supply source on OUT. The IC current sinks if there is an external supply voltage applied to OUT
when in disabled mode. For best perfomance, a 4.7-µF low-ESR capacitor is recommended.
TERMPWR: (Supply voltage pin) The pin should be decoupled with at least a 2.2-µF low-ESR output capacitor.
For best perfomance, a 4.7-µF low-ESR capacitor is recommended. Lead lengths should be kept at a minimum.
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3
SLUS213B – APRIL 1998 – REVISED FEBRUARY 2001
APPLICATION INFORMATION
TYPICAL SCSI BUS CONFIGURATION
TYPICAL WIDE SCSI BUS CONFIGURATION
(18 TERMINATION LINES)
(27 TERMINATION LINES)
110Ω
110Ω
4.7µ F
4.7µF
TRMPWR 8
TRMPWR 8
OUT
OUT
ENBL 4
ENBL 4
1
1
4.7µ F
4.7µF
2
2
GND
GND
Figure 1
Figure 2
UDG–00075
UDG–00076
TYPICAL CHARACTERISTICS
DROPOUT VOLTAGE
vs
TEMPERATURE
OUTPUT VOLTAGE
vs
TEMPERATURE
2.90
Output Voltage – V
2.88
Dropout Voltage – (VIN–VOUT) – V
1.3
IOUT = 300 mA
2.86
2.84
IOUT = –750 mA
VOUT = 2.75 V
1.2
1.1
1.0
0.9
0.8
No Load
2.82
IOUT = –750 mA
0.7
2.80
0.6
0
20
40
Temperature – C
60
80
0
40
60
Temperature – C
Figure 4
Figure 3
4
20
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80
SLUS213B – APRIL 1998 – REVISED FEBRUARY 2001
LINE REGULATION
vs
TEMPERATURE
LOAD REGULATION
vs
TEMPERATURE
4
30
IOUT = 300 mA to –750 mA
TRMPWR = 4 V to 6 V
2
28
Line Regulation – mV
Load Regulation – mV
0
26
24
–2
–4
–6
–8
22
–10
20
0
20
40
Temperature – C
60
80
–12
0
20
40
60
Temperature – C
80
Figure 6
Figure 5
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5
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