DS2120E

Overview

The DS2120E is an Ultra3 LVD SCSI terminator manufactured by Analog Devices Inc./Maxim Integrated. It provides low-voltage differential termination for nine signal line pairs in a 28-pin TSSOP package. The device operates within a voltage range of 4.75V to 5.25V and consumes up to 95mA of supply current. It supports an operating temperature range from 0°C to +70°C. Key electrical parameters include a typical differential mode termination resistance of 110Ω, a common mode termination resistance of 150Ω, and an output capacitance of 3pF. The component integrates precision laser-trimmed resistors and includes built-in thermal shutdown circuitry.

Feature Summary

• Fully compliant with Ultra3, Ultra160, Ultra320, and Ultra2 (LVD only) SCSI standards
• Integrates zero temperature coefficient termination resistors with 5% tolerance on LVD termination resistance
• Features automatic autoselection of LVD termination based on bus voltage sensing
• Includes built-in mode change filter/delay and on-board thermal shutdown circuitry

Applications

• Raid Systems
• SCSI Host Bus Adapter Cards (HBA)
• Servers
• Network Attached Storage (NAS)
• Storage Area Networks (SANs)

Procurement Notes

Verify the specific ordering suffix to confirm the package type and tape/reel configuration. Confirm RoHS compliance status as indicated by the '+' designation. Ensure the procurement source provides valid documentation matching the manufacturer's part number specifications.

Selection Notes

Select this component for systems requiring Ultra3 LVD SCSI termination. Verify that the system environment remains within the specified 0°C to +70°C operating temperature range. Ensure the design accommodates the 28-pin TSSOP footprint and connects the TPWR pin to the SCSI bus TERMPWR line for proper operation.

Part Context

The DS2120E belongs to the DS2120 family of Ultra3 LVD SCSI terminators. It serves as a critical interface component for managing signal integrity on SCSI buses. The device ensures compatibility with various SCSI standards by automatically isolating from the bus when non-LVD devices are detected.

Replacement Considerations

DS2120B

FAQ

How does the DS2120E handle single-ended or high-voltage differential devices?

The DS2120E detects SE or HVD devices via the DIFFSENS line and automatically disconnects its termination pins from the bus to prevent interference.

What is the purpose of the DIFF_CAP pin?

The DIFF_CAP pin monitors the DIFFSENS line to determine the proper operating mode and requires a 0.1µF capacitor for filtering.

What happens during thermal shutdown?

During thermal shutdown, the termination pins are isolated from the SCSI bus, VREF becomes high impedance, and the DIFFSENS driver is shut down.