SN75LVDM976

www.ti.com SN75LVDM976 SN75LVDM977 SLLS292B – APRIL 1998 – REVISED JANUARY 2000 9-CHANNEL DUAL-MODE TRANSCEIVERS FEATURES 9 Channels for the Data and Control Paths of the Small Computer Systems Interface (SCSI) Supports Single-Ended and Low-Voltage Differential (LVD) SCSI CMOS Input Levels ('LVDM976) or TTL Input Levels ('LVDM977) Available Includes DIFFSENS Comparators on CDE0 Single-Ended Receivers Include Noise Pulse Rejection Circuitry Packaged in Thin Shrink Small-Outline Package With 20-Mil Terminal Pitch Low Disabled Supply Current 7 mA Maximum Power-Up/Down Glitch Protection Bus is High-Impedance With VCC = 1.5 V Pin-Compatible With the SN75976ADGG High-Voltage Differential Transceiver DESCRIPTION The SN75LVDM976 and SN75LVDM977 have nine transceivers for transmitting or receiving the signals to or from a SCSI data bus. They offer electrical compatibility to both the single-ended signaling of X3.277:1996-SCSI-3 Parallel Interface (Fast-20) and the new low-voltage differential signaling method of proposed standard 1142-D SCSI Parallel Interface – 2 (SPI-2). The differential drivers are nonsymmetrical. The SCSI bus uses a dc bias on the line to allow terminated fail safe and wired-OR signaling. This bias can be as high as 125 mV and induces a difference in the high-to-low and low-to-high transition times of a symmetrical driver. In order to reduce pulse skew, an LVD SCSI driver's output characteristics become nonsymmetrical. In other words, there i...