SS7519

SS7519 Multi-mode SCSI Terminator FEATURES !" Meets SCSI-1, SCSI-2, Ultra3 and Ultra320 Standards. !" Auto-selectable Multimode single-ended or Low Voltage Differential termination. !" Current limit and thermal shutdown protection. !" Ground driver integrated for single-ended operation !" Compatible with active-negation drivers. Single-Ended resistor will maintain 110Ω ± 5 % . For LVD termination, the SS7519 integrates two current sources with nine accuracy resistor strings. This architecture yields a 105Ω ±5% differential and 226Ω ±10% common mode impedance. A fail-safe bias of 110mV is sustained when no drivers are connected to the SCSI bus. If the SS7519 detects a HVD SCSI device on the bus, all the signals will be set to a high impedance state. DESCRIPTION The SS7519 multimode SCSI terminator is both a single-ended and a low voltage differential terminator that meets the specifications of SCSI Parallel Interface (SPI-4). The SS7519 also provides backward compatibility to the SCSI-1, SCSI-2 and Single-Ended specifications. The Multimode terminator contains all the functions required to terminate and auto detect for SCSI devices without hardware fluctuation. Auto-Selectable is achieved by using voltage detection on the DIFFSENSE signal. The SS7519 senses the DIFFSENSE line while sourcing the DIFFSENSE signal with LVD levels. The DIFFSENSE line being grounded indicates that one or more SE devices are attached on the bus. The SS7519 switches to the termination mode that is a...