DS2119ME

Overview

The DS2119ME is a multimode SCSI terminator supporting Low-Voltage Differential (LVD) and Single-Ended (SE) termination for nine signal line pairs. It operates at 5V with a temperature range of 0°C to +70°C in a 28-pin TSSOP package. The device provides 110Ω SE resistance and 105Ω differential LVD resistance. It features automatic mode selection via the DIFFSENS line, low power-down capacitance of 3pF, and on-board thermal shutdown. Three units are required for a wide SCSI bus.

Feature Summary

• Multimode operation enables seamless transition between LVD and SE termination based on bus voltage sensing.
• Integrated DIFFSENSE driver and digital filtering eliminate external components for mode detection.
• Supports actively negated SE SCSI signals with high output current capability.
• Includes thermal shutdown circuitry that isolates termination pins during overtemperature events.

Applications

• Ultra320 and Ultra160 SCSI host adapters
• SCSI RAID controller cards
• Legacy SE SCSI peripheral interfaces

Procurement Notes

Verify component authenticity through authorized distributors or manufacturer channels. Confirm RoHS compliance status as indicated by the '+' suffix. Check datasheet revisions for any updates to electrical characteristics or pin configurations before finalizing procurement specifications.

Selection Notes

Select this component for designs requiring backward compatibility with legacy single-ended devices while supporting modern low-voltage differential signaling. Ensure adequate decoupling capacitors are placed near TPWR and VREF pins to maintain regulation stability under varying load conditions.

Part Context

Part of the Maxim Integrated DS2119M family of SCSI interface controllers. Designed to simplify system integration by combining termination logic with mode detection capabilities in a compact surface-mount package suitable for high-density PCB layouts.

Replacement Considerations

DS2119ME+T&R offers identical functionality in tape and reel packaging for automated assembly processes.

FAQ

How does the DS2119ME determine the active termination mode?

It monitors the voltage on the SCSI DIFFSENS line using internal comparators to automatically switch between LVD and SE termination modes.

What is the purpose of the ISO pin?

Pulling the ISO pin high isolates the termination pins from the SCSI bus, which is useful during hot-plug operations or when HVD devices are detected.

Can this device support actively negated SE signals?

Yes, the DS2119ME fully supports actively negated SE SCSI signals, capable of sinking 22mA per line while maintaining stable reference voltages.