DS21S07AE/T&R

Overview

The DS21S07AE/T&R is a SCSI terminator IC manufactured by Analog Devices Inc./Maxim Integrated, designed for Fast and Ultra SCSI systems. It integrates a low-dropout voltage regulator and nine laser-trimmed 110Ω termination resistors with 2% tolerance into a monolithic chip. The device operates within a TERMPWR voltage range of 4.00V to 5.50V and supports an operating temperature range of 0°C to +70°C. Packaged in a 20-pin Thin Shrink Small Outline Package (TSSOP), it provides active termination for nine signal lines, ensuring enhanced noise immunity and intrinsic power decoupling.

Feature Summary

• Fully compliant with SCSI-1, Fast SCSI, and Ultra SCSI standards
• Integrates a low-dropout voltage regulator and nine precise switched 110Ω termination resistors
• Features a power-down mode that electrically isolates the termination resistors from the SCSI bus
• Includes on-board thermal shutdown circuitry for protection

Applications

• Active termination at both ends of cable segments in SCSI systems with single-ended drivers and receivers
• Termination for disk drives and RAID system components
• Peripheral devices acting as targets on a SCSI bus

Procurement Notes

Verify component authenticity through authorized distributors or manufacturer channels. Confirm package type matches the 20-pin TSSOP specification. Check datasheet revisions for any updates to electrical characteristics or pin configurations before integration into designs.

Selection Notes

Select this component for applications requiring compliance with Fast and Ultra SCSI standards. Ensure the design accommodates the 20-pin TSSOP footprint. Verify that the system TERMPWR line falls within the 4.00V to 5.50V operating range and that thermal management meets the 0°C to +70°C requirement.

Part Context

The DS21S07A series serves as an active terminator for SCSI interfaces. The 'E' suffix denotes the 20-pin TSSOP package variant, while '/T&R' indicates tape and reel packaging. This part is backward compatible with earlier models like the DS2107 and DS2107A, offering improved performance through integrated regulation and precise resistance trimming.

Replacement Considerations

The DS21S07AS is a pin-compatible alternative packaged in a 16-pin SOIC format. Designers must verify board layout compatibility when switching between the 20-pin TSSOP and 16-pin SO packages.