Texas Instruments UC5603QPTR, UC5603QP, UC5603N, UC5603J, UC5603DPTR Datasheet

• Complies with SCSI, SCSI-2 and

SPI-2 Standards

• 6pF Channel Capacitance during
Disconnect

• 100µA Supply Current in
Disconnect Mode

• Meets SCSI Hot Plugging

• -400mA Sourcing Current for

Termination

• +400mA Sinking Current for
Active Negation Drivers

• Logic Command Disconnects all
Termination Lines

• Trimmed Termination Current to
3%

• Trimmed Impedance to 3%

• Negative Clamping on all Signal

Lines

• Current Limit and Thermal
Shutdown Protection

The UC5603 provides 9 lines of active termination for a SCSI (Small Comput­ers Systems Interface) parallel bus. The SCSI standard recommends active
termination at both ends of the cable segment.

The UC5603 provides a disconnect feature which, when opened or driven
high, will disconnect all terminating resistors, and disables the regulator;
greatly red uc ing standby power. The output channels remain high impedance
even without Termpwr applied. A low channel capacitance of 6pF allows units
at interim points of the bus to have little to no effect on the signal integrity.

Functionall y the UC5603 is s imilar to its pr edecessor, the UC5601 - 18 line
Active Terminator. Several electrical enhancements were incorporated in the
UC5603, suc h as a sink/source re gulator output stage t o accommodate all
signal lin es at + 5V, while the regulator remains at its nominal value, reduced
channel cap acitance to 6pF typical, and as with the UC5601, custom power
packages are utilized to allow normal operation at full power conditions (1.2
watts).

Internal ci rcuit trimming is uti lized, first to trim the impedance to a 3% toler­ance, and then mo st imp ort antl y, to trim the output current to a 3% tolerance,
as close to the max SCSI spec as possible, which maximizes noise margin in
fast SCSI operation.

Other feat ures include negative cl amping on all signal lines to protect exter­nal circuitry from latch-up, thermal shutdown and current limit.

This device is offered in low thermal resistance versions of the industry stand­ard 16 pin narrow body S OIC, 16 pin ZIP (zig-zag in line pac kage) and 24 pin
TSSOP.

UC5603

9-Line SCSI Active Terminator

FEATURES DESCRIPTION

BLOCK DIAGRAM

Circuit Design Patented

3/97

UDG-94049

DIL-16 (Top View)
N or J Package

* DP packag e pi n 5 se rves as signal ground; pins 4, 12, 13
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.

UC5603

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

ABSOLUTE MAXIMUM RATINGS

Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.8V to 5.25V

Signal Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +5V

Disconnect Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to Termpwr

RECOMMENDED OPERATING CONDITIONS

CONNECTION DIAGRAMS

Unless otherwise sp ec ified all voltages are with respe ct to Ground. 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.

* PWP package pin 5 serves as signal ground; pin s 6, 7, 8, 9,
17, 18, 19, and 20 serve as heatsink/ground.

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