UCC5640PW28

Overview

The UCC5640PW28 is an active Y-terminator designed for low voltage differential (LVD) SCSI networks. It operates within a TRMPWR supply range of 2.7 V to 5.25 V and supports Ultra2, Ultra3, Ultra160, and Ultra320 standards. The device provides a differential impedance of 105 Ω and a common mode impedance of 150 Ω. It features a 1.5-pF channel capacitance per line pair to minimize bus loading. Electrical characteristics include a 1.25 V regulator with ±100 mA source/sink capability and a 1.3 V DIFSENS driver. The component is housed in a 28-pin TSSOP package.

Feature Summary

• Active termination that automatically detects LVD, SE, or HVD drivers on the SCSI bus
• Integrated high-power differential output stage capable of driving up to 15 mA source current
• Differential failsafe bias ensures defined logic states when the bus is not driven
• Disconnect input pin allows power-down of regulators when the terminator is not at the bus end

Applications

• Low Voltage Differential (LVD) SCSI bus termination
• SPI-2 Ultra2 (Fast-40) compliant systems
• SPI-3 Ultra3 / Ultra160 (Fast-80) compliant systems
• SPI-4 Fast-160 / Ultra320 compliant systems

Procurement Notes

Verify the specific ordering suffix against the manufacturer's documentation to confirm the exact package type and reel configuration. Confirm that the procurement matches the required temperature grade and RoHS compliance status specified in the datasheet. Ensure the supplier provides valid traceability documents for the electronic components.

Selection Notes

Select this component specifically for LVD-only SCSI environments where single-ended or high-voltage differential support is not required. Verify that the system design accommodates the requirement of using three devices per bus end to terminate all data and control lines. Ensure layout constraints regarding capacitance balancing are met to maintain signal integrity.

Part Context

This device belongs to the UCC5640 family of active terminators. The PW28 designation indicates the 28-pin Thin Shrink Small Outline Package variant. A 24-pin version (UCC5640PW24) exists for designs requiring fewer pins. Both variants share identical electrical performance and functionality.

Replacement Considerations

Public confirmed substitute part numbers: UCC5640PW24.