The wireless communication solution provider
Ultra Multimode LVD/SE SCSI Terminator
FEATURES
AR7519
Y Meets SCSI-1, SCSI-2, Ultra2, and Ultra3/Ultra160 standards. Y Auto-selectable multimode for single-ended or low voltage differential termination. Y Current limit and thermal shutdown protection. Ground driver integrated for single-ended operation Y SCSI bus hot-swap compatible. Y Compatible with active negation drivers.
APPLICATIONS
PC server Workstation
DESCRIPTION
The AR7519 multimode SCSI terminator is both a single-ended (SE) and a low voltage differential (LVD) terminator that meets the specification of SCSI parallel interface (SPI-3). In addition, the AR7519 provides backward compatibility to the SCSI-1, SCSI-2, and SE specifications. The multimode terminator contains all functions required to terminate and auto detect for SCSI devices without hardware fluctuation. Auto-selection is achieved by using voltage detection on the DIFFSENSE signal. The AR7519 senses the DIFFSENSE line while sourcing the DIFFSENSE signal with the LVD levels. The DIFFSENSE line being grounded indicates that one or more SE devices are attached on the bus. The AR7519 switches to the termination mode that is appropriate for the bus based on the value of the DIFFSENSE input voltage. For the SE termination, the active terminator will pull RXN to 2.85V and RXP to hard ground. The AR7519 can sink 22 mA per line as required by SCSI specification. The SE resistor will maintain 110 5%. For the LVD termination, the AR7519 integrates two current sources with nine precision resistor strings. This architecture yields a 105 5% differential and 226 10% common mode impedance. A fail-safe bias of 110 mV is sustained when no drivers are connected to the SCSI bus. If the AR7519 detects a HVD SCSI device on the bus, all the signals will be set to a high impedance state.
The wireless communication solution provider
|
