SIP5678CS-TR Vishay, SIP5678CS-TR Datasheet - Page 10

• Manufacturer Part Number: SIP5678CS-TR
• Description: 15-Line Scsi Bus Terminators
• Manufacturer: Vishay
• Type: SCSI Terminationr

Specifications of SIP5678CS-TR

• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.25V
• Mounting: Surface Mount
• Operating Temperature Classification: Commercial
• Lead Free Status / RoHS Status: Not Compliant

SiP5678
Vishay Siliconix
DETAILED OPERATION
The SiP5678 is a multimode active terminator IC, which
detects the operating mode of the SCSI bus, and switches to
the appropriate termination configuration accordingly.
Two SiP5678 terminators are required at each end of a wide
SCSI bus to terminate 27 lines (18 data, 9 control). In LVD
mode the SiP5678 provides 105 Ω differential impedance
and 112 mV differential bias between each TN/TP pair of
terminator lines. In S/E mode the SiP5678 provides 108 Ω
impedance and 2.7 V pull-up on each TxN pin, and low
impedance to ground on each TxP pin. In HPD mode the
SiP5678 disconnects from the bus and presents high
impedance to all TN/TP lines.
Each SiP5678 IC has a 1.3 V DIFFSENS regulator output
that can be used to drive the DIFFSENS line of a SCSI bus.
The DIFFSENS regulator attempts to drive the DIFFSENS
control signal to 1.3 V, but is current limited so that S/E or
HPD devices on the SCSI bus can override the DIFFSENS
regulator and put the bus into S/E or HPD mode of operation.
The MODE pin senses the operational state of the SCSI bus
by detecting the voltage on the DIFFSENS control line.
There is an integrated 200 ms glich filter on the MODE input
for reliable operation in a noisy environments.
Vishay Siliconix maintains worldwide manufacturing capability. Products may be manufactured at one of several qualified locations. Reliability data for Silicon
Technology and Package Reliability represent a composite of all qualified locations. For related documents such as package/tape drawings, part marking, and
reliability data, see www.vishay.com/ppg?73100.
www.vishay.com
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On power up, the SiP5678 initially defaults to a high
impedance state on the termination pins. If the MODE pin
detects S/E or LVD level on the DIFFSENS signal of the
SCSI bus the SiP5678 will wait a standard delay (200 ms
typical) before changing its operating mode. During regular
operation if the MODE pin detects another bus mode change
the SiP5678 again waits a standard delay before changing
its operating mode. This mode change delay is implemented
in accordance with SCSI standards SPI-3 and higher.
The DISABLE pin is used to connect/disconnect the
SiP5678. If it is pulled to GROUND the SiP5678 is in connect
mode, and operates as a terminator. If it is pulled to
TRMPWR or left open the device is in disconnect mode and
presents high impedance to the SCSI bus. In disconnect
mode the DIFFSENS regulator is disabled.
The SiP5678 operates within SCSI specifications with the
TERMPWR voltage between 2.7 V and 5.25 V, which
enables it to operate in both 5 V and 3.3 V systems. The
2.7 V lower limit guarantees correct performance in a 3.3 V
system.
S09-1456-Rev. B, 03-Aug-09
Document Number: 73100