Texas Instruments UC5602QPTR, UC5602QP, UC5602DWPTR, UC5602DWP Datasheet

UC5602

SCSI Active Terminator

FEATURES

∙Complies with SCSI, SCSI-2 Standards

∙10pF Channel Capacitance During Disconnect

∙Active Termination for 18 Lines

∙Logic Command Disconnects all Termination Lines

∙Low Supply Current in Disconnect Mode

∙Trimmed Regulator for Accurate Termination Current

∙Current Limit and Thermal Shutdown Protection

∙110 Ohm Termination

∙Meets SCSI Hot Plugging

DESCRIPTION

The UC5602 is a pin compatible version of its predecessor, the UC5601, and is targeted for high volume applications which require active termination, but not the high performance of the UC5601. The major differences are relaxed output current and termination tolerances, and the absence of low side clamps.

The UC5602 provides 18 lines of active termination for a SCSI (Small Computer Systems Interface) parallel bus. The SCSI-2 standard recommends active termination at both ends of the cable segment, and SCSI-3 will make it a requirement.

The UC5602 provides a disconnect feature which, when opened or driven high, will disconnect all terminating resistors, and disables the regulator; greatly reducing standby power. The output channels remain high impedance even without Termpwr applied.

Internal circuit trimming is utilized, first to trim the impedance to a 7% tolerance; and then most importantly, to trim the output current 7% tolerance, as close to the max SCSI as possible, which maximizes noise margin in fast SCSI operation.

Other features include thermal shutdown, current limit, and 40mA of active negation sink current capability.

This device is offered in low thermal resistance versions of the industry standard 28 pin wide body SOIC and PLCC, as well as a 24 pin DIL plastic package.

BLOCK DIAGRAM

UDG-94052

Circuit Design Patented

10/94

ABSOLUTE MAXIMUM RATINGS

Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +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

Unless otherwise specified all voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal.

Consult Packaging Section of Unitrode Integrated Circuits databook for thermal limitations and considerations of packages.

RECOMMENDED OPERATING CONDITIONS

Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . 4.0V to 5.25V Signal Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +3V Disconnect Input Voltage . . . . . . . . . . . . . . . . . . 0V to Termpwr

UC5602

CONNECTION DIAGRAMS

PLCC-28 (Top View)

QP Package

* QP package pins 12 - 18 serve as both heatsink and signal ground.

SOIC-28 (Top View)

DIL-24 (Top View)

DWP Package

N Package

* 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.

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