GENERAL DESCRIPTION

Fast SCSI and Ultra SCSI require the use of active terminations at both ends of every cable segment in a SCSI system with single-ended drivers and receivers. The DS21S07A SCSI terminator, which is fully compliant with these standards, enables the designer to gain the benefits of active termination: greater immunity to voltage drops on the TERMPWR (TERMination PoWeR) line, enhanced high-level noise immunity, intrinsic TERMPWR decoupling, and very low quiescent current consumption. The DS21S07A integrates a regulator and nine precise switched 110Ω termination resistors into a monolithic IC. The DS21S07A can be electrically isolated from the SCSI bus without physical removal from the SCSI device.

FEATURES

■ Fully Compliant with SCSI-1, Fast SCSI, and Ultra SCSI

■ Backward Compatible to the DS2107 and DS2107A

■ Provides Active Termination for Nine Signal Lines

■ Laser-Trimmed 110Ω Termination Resistors Have 2% Tolerance

■ Low Drop-Out Voltage Regulator

■ Power-Down Mode Isolates Termination Resistors from the Bus

■ SCSI Bus Hot Plug Compatible

■ Fully Supports Actively Negated SCSI Signals

■ On-Board Thermal Shutdown Circuitry

■ 16-Pin Plastic SO (DS21S07AS) and 20-Pin Plastic TSSOP (Thin Shrink Small Outline Package) (DS21S07AE)