Texas Instruments UCC5622MWPTR, UCC5622MWP, UCC5622FQPTR, UCC5622FQP Datasheet

DESCRIPTION

The UCC5622 provides 27 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.

The UCC5622 is ideal for high performance 5V SCSI systems. During dis­connect the supply current is typically only 100µA, which makes the IC at­tractive for lower powered systems.

The UCC5622 features a split disconnect allowing the user to control termi­nation lines 10 to 27 with disconnect one, DISCNCT1, and control terminia­tion lines 1 to 9 with disconnect two, DISCNCT2.

The UCC5622 is designed with a low channel capacitance of 2.5pF, which
eliminates effects on signal integrity from disconnected terminators at in­terim points on the bus.

The power amplifier output stage allows the UCC5622 to source full termi­nation current and sink active negation current when all termination lines
are actively negated.

The UCC5622, as with all Unitrode terminators, is completely hot plugga­ble and appears as high impedance at the teminating channels with
V

TRMPWR

= 0V or open.

Internal circuit trimming is utilized, first to trim the 110Ω impedance, and
then most importantly, to trim the output current as close to the maximum
SCSI-3 specification as possible, which maximizes noise margin in FAST­20 SCSI operation.

(continued)

UCC5622

27 - Line SCSI Terminator With Split Disconnect

BLOCK DIAGRAM

FEATURES

• Complies with SCSI, SCSI-2, SCSI-3,
SPI and FAST-20 (Ultra) Standards

• 2.5pF Channel Capacitance During
Disconnect

• 100µA Supply Current in Disconnect
Mode

• 4V To 7V Operation

• 110Ω Termination

• Completely Meets SCSI Hot Plugging

• –900mA Sourcing Current for

Termination

• +500mA Sinking Current for Active
Negation

• Logic Command Disconnects all
Termination Lines

• Split Disconnect Controls Lines 1 to 9
and 10 to 27 Separately

• Trimmed Impedance to 5%

• Current Limit and Thermal Shutdown

Protection

10/98

UDG-96113

Circuit Design Patented

2

UCC5622

Other features include thermal shutdown and current limit.
This device is offered in low thermal resistance versions
of the industry standard 44 pin wide body QSOP (MWP)
and 48 pin LQFP (FQP). Consult QSOP-44 and LQFP-48
Packaging Diagram for exact dimensions.

DESCRIPTION (cont.)

CONNECTION DIAGRAM

SSOP-44 (Top View)
MWP Package

LQFP-48 (Top View)
MWP Package

ABSOLUTE MAXIMUM RATINGS

TRMPWR Voltage................................+7V

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

Regulator Output Current..........................1.5A

Storage Temperature ...................-65°C to +150°C

Junction Temperature...................-55°C to +150°C

Lead Temperature (Soldering, 10 Sec.).............+300°C

Currents are positive into, negative out of the specified termi­nal. Consult Packaging Section of Databook for thermal limita­tions and considerations of packages.

ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for T

A

= 0°C to 70°C,

TRMPWR = 4.75V, DISCNCT1 = DSCNCT2 = 0V, TA=TJ.

PARAMETER TEST CONDITIONS MIN TYP MAX UNITS

Supply Current Section

TRMPWR Supply Current All Termination Lines = Open 1 2 mA

All Termination Lines = 0.2V 630 650 mA

Power Down Mode DISCNCT1 = DSCNCT2 = TRMPWR 100 200 µA