DS2119ME+T&R

Overview

The DS2119ME+T&R is an Ultra3 LVD/SE SCSI terminator manufactured by Analog Devices Inc./Maxim Integrated. It provides multimode termination for nine signal line pairs, supporting SPI-2 through Ultra320 standards. The device operates on a 5V supply within a 0°C to +70°C temperature range and is housed in a 28-pin TSSOP package with tape and reel packaging. Electrical specifications include a typical SE termination resistance of 110Ω and differential mode termination resistance of 110Ω. The output capacitance is typically 3pF, and the device features integrated thermal shutdown circuitry.

Feature Summary

• Autoselection between Low-Voltage Differential (LVD) and Single-Ended (SE) termination modes based on bus voltage sensing
• Integrated thermal shutdown circuitry to protect against overheating conditions
• Supports actively negated SE SCSI signals with high current sinking capability per line
• Built-in digital filtering on the DIFFSENS control line to prevent erroneous mode switching

Applications

• SCSI Parallel Interface (SPI-2, SPI-3, SPI-4) compliant systems
• Ultra160 and Ultra320 SCSI bus implementations
• Legacy SE SCSI backward compatibility integration with modern LVD devices

Procurement Notes

Verify component authenticity and RoHS compliance status prior to acquisition. Confirm that the tape and reel packaging matches specific manufacturing lot requirements. Ensure the ordering suffix corresponds to the intended bulk quantity constraints. Validate that the lead-free designation aligns with environmental regulations applicable to the target deployment region.

Selection Notes

Select this component when designing SCSI interfaces requiring automatic transition between LVD and SE modes without external logic. Verify that the system power supply remains stable within the 4V to 5.5V operating range. Ensure adequate decoupling capacitors are placed near the TPWR and VREF pins to maintain signal integrity and proper regulator performance during high-speed data transfers.

Part Context

This part belongs to the DS2119M series of SCSI interface controllers. It serves as a specialized termination solution for high-speed parallel data buses. The device integrates precision resistor strings and current sources to replace discrete termination networks, simplifying PCB layout while maintaining strict impedance control across varying bus configurations.

Replacement Considerations

DS2119ME

FAQ

How does the DS2119ME+T&R determine whether to use LVD or SE termination?

The device uses internal DIFFSENSE circuitry to monitor the SCSI bus DIFFSENS line voltage. If the voltage indicates an LVD environment, it applies LVD termination; if SE devices are detected, it switches to SE termination automatically.

What is the function of the ISO pin on the DS2119ME+T&R?

When pulled high, the ISO pin isolates the termination pins from the SCSI bus. This feature is utilized during High-Voltage Differential (HVD) detection or thermal shutdown events to protect the device and bus signals.

What are the recommended decoupling capacitor values for the DS2119ME+T&R?

A 4.7µF capacitor is required between the VREF pin and ground. Additionally, a 2.2µF capacitor and a 0.01µF high-frequency capacitor are recommended between the TPWR pin and ground, placed close to the device.