Texas Instruments UC5607DWPTR, UC5607DWP Datasheet

FEATURES

• Complies with SCSI and SCSI-2
Standards

• 8pF Channel Capacitance during
Disconnect

• SCSI Plug and Play, Dual Low
Disconnect, Logic Low Command
Disconnects All Termination Lines

• Meets SCSI Hot Plugging Capability

• -650mA Sourcing Current for

Termination

• +200mA Sinking Current for Active
Negation

• 200µA Supply Current in Disconnect
Mode

• Trimmed Termination Current to 7%

• Trimmed Impedance to 7%

• Provides Active Termination for 18

Lines

UC5607

Plug and Play, 18-Line SCSI Active Terminator

BLOCK DIAGRAM

7/98

UDG-94124

Connect Connect Connect Disc

DISCNCT1

1010

DISCNCT2 0110

DESCRIPTION

The UC5607 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 UC5607 provides a low disconnect feature which will disconnect all
terminating resistors, and will disable the regulator, greatly reducing
standby power. The output channels remain high impedance even without
Termpwr applied.

The UC5607 terminator is specially designed with two disconnect pins for
full SCSI Plug and Play (PnP) applications.

Custom power packages are utilized to allow normal operation at full
power conditions (2 Watts).

Internal circuit trimming is utilized, first to trim the impedance to a 7% tol­erance, and then most importantly, to trim the output current to a 7% toler­ance, as close to the max SCSI spec as possible, which maximizes 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 28 pin wide body SOIC, and 28 pin PLCC, as well as 24 pin DIP.

Circuit Design Patented

2

UC5607

ABSOLUTE MAXIMUM RATINGS

Termpwr Voltage.................................+7V

Signal Line Voltage ..........................0Vto+7V

Regulator Output Current ...........................1A

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 .........................3.8V to 5.25V

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

Disconnect Input Voltage ..................0VtoTermpwr

CONNECTION DIAGRAMS

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

** DISCNCT2

is internally tied to ground.

* DWP package pin 8 serves as signal ground; pins 7, 8, 9, 20,
21, 22 serve as heatsink/ground.

Note: Drawings are not to scale.

PLCC-28 (Top View)
QP Package

SOIC-28 (Top View)
DWP Package

DIL-24 (Top View)
NorJPackage