• Complies with SCSI, SCSI-2
Standards
• 9pF Channel Capacitance during
Disconnect
• 100µA Supply Current in
Disconnect Mode
• Meets SCSI Hot Plugging Capability
•−300mA Sourcing Current for
Termination
• +40mA Sinking Current for Active
Negation
• Logic Command Disconnects all
Termination Lines
• Trimmed Termination Current to 7%
• Trimmed Impedance to 7%
• Current Limit and Thermal
Shutdown Protection
The UC5604 provides 9 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 UC5604 provides a disconnect feature which, when opened or driven
high, will disconnect all terminating resistors and disable the regulator,
greatly redu cing stan dby power. The output c hannels remain high impedance even without Termpwr applied.
The UC5604 is pin-for-pin compatibl e with its predeces sor, the UC5603 - 9
line Active Terminator. The only functiona l differ ence be twee n the UC5604
and UC5603 is the absence of the negative clamps. Parametrically, the
UC5604 has a 7 % tol er ance o n im peda nce and current compared to a 3%
tolerance on the UC5603 and the sink current is reduced from 300mA to
40mA. Custom power packages are utilized to allow normal operation at
full power conditions (1.2 watts).
Internal circuit trimming is utilized, first to trim the impedance to a 7% tolerance, and the n most importantly, to trim the output current to a 7% tolerance, as close to the max SCSI spec as possible, which maximiz es noise
margin in fast SCSI operation.
Other features include thermal shutdown and current limit.
This device is offered in low thermal resistance versions of the industry
standard 16 pin narrow body SO IC, 16 pin ZIP (zig-zag in line package)
and 24 pin TSSOP.
UC5604
9-Line Low Capacitance SCSI Active Terminator
FEATURES DESCRIPTION
BLOCK DIAGRAM
Circuit Design Patented
3/97
UDG-94064
ABSOLUTE MAXIMUM RATINGS
Termpwr Vo ltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V
Signal Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +7V
Regulator Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5A
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to +150°C
Operating Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −55°C to +150°C
Lead Temperature (Soldering, 10 Sec.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +300°C
RECOMMENDED OPERATING CONDITIONS
Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.8V to 5.25V
Signal Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +5V
Disconnect Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to Termpwr
CONNECTION DIAGRAMS
DIL-16 (Top View)
N or J Package
UC5604
* DP packag e pi n 5 se rves as signal ground; pin s 4, 12, 13
serve as heatsink/ground.
* PWP package pin 5 serves as signal ground; pins 6, 7, 8, 9,
17, 18, 19, and 20 serve as heatsink/ground.
ZIP-16 (Top View)
Z Package
SOIC-16 (Top View)
DP Package
TSSOP-24 (To p View)
PWP Package
Note: Drawings are not to scale.
Unless otherwise sp ec ified all voltages are with respect to G round. Currents are positive into, negative out of the specified terminal.
Consult Packaging Section of Unitrode Integrated Circuits databook for thermal limitations and consid era ti on s of pac ka ges.
2
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Supply Current Section
Termpwr Supply Current All termination lines = Open 14 20 mA
All termination li ne s = 0. 5V 200 220 mA
Power Down Mode DISCNCT = Open 100 150 µA
Output Section (Termina tor Li ne s)
Terminator Impedance ∆I
LINE
= -5mA to -15mA 97 110 129 Ohms
Output High Voltage TRMPWR = 4V (Note 1) 0°C < T
J
< 70°C2.55 3.2 V
T
J
= 25°C 2.6 2.9 3.1 V
Max Output Cur r e nt V
LINE
= 0.5V TJ = 25°C -19.5 - 2 1.9 -22.4 mA
0°C < T
J
< 70°C -18.5 -21.9 -22.4 mA
Max Output Cur r e nt V
LINE
= 0.5V, TRMPWR = 4V (Note 1) TJ = 25°C -18.0 -21.9 -22.4 mA
0°C < T
J
< 70°C -17.0 -21.9 -22.4 mA
Output Clamp Level I
LINE
= -30mA -0.2 -0.05 0.1 V
Output Leakage
DISCNCT = 4V
TRMPWR = 0V to 5.25V
REG = 0V
V
LINE
= 0 to 4V 10 400 nA
V
LINE
= 5.25V 100 µA
TRMPWR = 0V to 5.25V, REG = Open
V
LINE
= 0V to 5.25V
10 400 nA
Output Capacitance DISCNCT = Open (Note 2) 9 12 pF
Regulator Section
Regulator Output Voltage 2.5 2.9 3.2 V
Regulator Outpu t Voltage All Termination Line s = 5V 2.55 2.9 3.1 V
Line Regulation TRMPWR = 4V to 6V 10 20 mV
Load Regulation I
REG
= +100mA to -100mA 20 50 mV
Drop Out Voltage All Termination Lines = 0.5V 1.0 1.2 V
Short Circuit Current V
REG
= 0V -200 -400 -600 mA
Sinking Current Capability V
REG
= 3.5V 20 40 mA
Thermal Shutdown 170 °C
Thermal Shutdown Hysteresis 10 °C
Disconnect Section
Disconnect Threshold 1.1 1.4 1.7 V
Threshold Hysteresis 100 mV
Input Current DISCNCT = 0V 150 200 µA
ELECTRICAL CHARACTERISTICS
Unless otherwise st at ed, th ese sp ecif icat io ns app ly for TA = 0°C to 70°C.
TRMPWR = 4.75V, DISCNCT = 0V. TA = TJ.
UC5604
Note 1: Measuring each terminatio n li ne wh il e ot he r 8 are lo w (0.5 V).
Note 2: Guaranteed by design. Not 10 0% tes te d in prod uc ti on .
Figure 1: Typical SCSI Bus Configurations Utilizing 2 UC5604 Devices
APPLICATION INFORMATION
UDG-94065
3
Figure 2: Typical Wide SCSI Bus Configurations Util iz in g 3 UC56 04 Devi ce s.
UC5604
UDG-94066
UNITRODE CORPORATI ON
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TEL. (603) 424- 24 10 • FAX (603) 424-3460
APPLICATION INFORMATION (cont.)
4
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