UCC5610_14 Datasheet, PDF (1/8 Pages) Texas Instruments – 18-LINE 3-5 VOLT LOW CAPACITANCE SCSI ACTIVE TERMINATOR

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D Complies With SPI-2 and SPI-3 Standards
D 2.75-V to 7-V Operation
D 1.8-pF Channel Capacitance during
Disconnect
D 0.5-µA Supply Current in Disconnect Mode
D 110-Ω/2.5-kΩ Programmable Termination
D Completely Meets SCSI Hot Plugging
UCC5610
18ĆLINE 3-5 VOLT LOW CAPACITANCE SCSI
ACTIVE TERMINATOR
SLUS362A − FEBRUARY 1997 − REVISED NOVEMBER 2000
D −650-mA Sourcing Current for Termination
D +400-mA Sinking Current for Active
Negation Drivers
D Trimmed Termination Current to 4%
D Trimmed Impedance to 7%
D Current Limit and Thermal Shutdown
Protection
description
The UCC5610 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.
The UCC5610 is ideal for high performance 3.3-V SCSI systems. The key features contributing to such low
operating voltage are the 0.1-V drop-out regulator and the 2.75-V reference. During disconnect the supply
current is typically only 0.5 µA, which makes the IC attractive for battery powered systems.
The UCC5610 is designed with an ultralow-channel capacitance of 1.8 pF, which eliminates effects on signal
integrity from disconnected terminators at interim points on the bus.
The UCC5610 can be programmed for either a 110-Ω or 2.5-kΩ termination. The 110-Ω termination is used for
standard SCSI bus lengths and the 2.5-kΩ termination is typically used in short bus applications. When driving
the TTL compatible DISCNCT pin directly, the 110-Ω termination is connected when the DISCNCT pin is driven
low, and disconnected when driven high. When the DISCNCT pin is driven through an impedance between
80 kΩ and 150 kΩ, the 2.5-kΩ termination is connected when the DISCNCT pin is driven low, and disconnected
when driven high.
block diagram
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UDG-94128-1
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