Texas Instruments UC5608DWP

Overview

UC5608DWP from Texas Instruments is an 18-line active SCSI terminator IC designed for parallel SCSI-2 and SPI-2 bus termination. It delivers ±650mA sourcing/sinking capability, 104.5–115.5Ω trimmed termination impedance (±5%), 6pF channel capacitance in disconnect mode, and operates from 4.0–5.25V Termpwr. It enables hot-pluggable, low-noise SCSI systems with thermal shutdown and current-limit protection.

For engineers reviewing the UC5608DWP datasheet, UC5608DWP pinout, UC5608DWP application, or UC5608DWP equivalent, key selection criteria include its 28-pin SOIC-DWP package, logic-controlled disconnect function, 100µA standby supply current, and compliance with SCSI hot-plug and active termination specifications.

Technical Context

The UC5608DWP integrates a precision 2.9V regulator with ≤20mV line regulation and 1.2V dropout, powering 18 matched termination channels. Each channel provides programmable sourcing (−650mA short-circuit) and sinking (+200mA) with trimmed current and impedance to ±5% tolerance-optimized for fast SCSI noise margin.

It implements logic-driven disconnect: pulling DISCNCT high disables all terminators and shuts down the regulator, reducing supply current to 100µA while maintaining high-impedance outputs even without Termpwr. The DWP package uses pins 7, 8, 9, 20, 21, 22 as heatsink/ground and pin 28 as signal ground.

Key Specifications

Pinout & Package

UC5608DWP is housed in a 28-pin wide-body SOIC package (DW suffix, PWP drawing), optimized for low thermal resistance and full-power operation up to 2 W. Pin 28 serves as signal ground; pins 7, 8, 9, 20, 21, and 22 are heatsink/ground terminals.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SCSI active termination applications.

Compared with UC5602DWP and AMCC 53CF94, the UC5608DWP offers superior noise margin via ±5% trimmed termination, higher sink current for active negation, and dedicated logic-controlled disconnect - making it optimal for modern SCSI-2 hot-plug and high-reliability embedded applications where standalone, precision termination is required.

Availability

UC5608DWP is available at Aetrix Electronics and suitable for SCSI-2 host adapters, industrial backplane termination, and legacy server maintenance requiring stable component supply and long-term obsolescence mitigation.

Supply support for UC5608DWP includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, specializing in analog, embedded processing, and connectivity technologies since 1930.

The UC5608DWP belongs to TI's legacy interface and termination product line, engineered specifically for robust, high-fidelity SCSI parallel bus implementation in mission-critical storage infrastructure.

FAQ

What is the primary function of the UC5608DWP in a SCSI system?

The UC5608DWP serves as an 18-line active terminator for SCSI-2 and SPI-2 parallel buses, providing precision-matched 110Ω termination with ±5% impedance and current tolerance. It regulates its own 2.9V bias rail and supports hot-plug operation via logic-controlled disconnect. The UC5608DWP ensures signal integrity at 10 MB/s transfer rates by minimizing reflections and maximizing noise margin - critical for reliable host-to-peripheral communication in storage subsystems.

Does the UC5608DWP require an external voltage reference or bias supply?

No. The UC5608DWP integrates a precision 2.9V regulator that derives its output from the Termpwr input (4.0–5.25V). This eliminates the need for external bias components and simplifies PCB layout. The regulator maintains ±0.1V accuracy with ≤20mV line regulation and 1.2V dropout - ensuring stable termination performance across the full Termpwr range. The UC5608DWP thus operates as a self-contained termination solution.

How does the UC5608DWP support SCSI hot-plugging?

The UC5608DWP supports SCSI hot-plugging through its logic-controlled DISCNCT input: asserting high on Pin 1 places all 18 termination channels into high-impedance state and shuts down the internal regulator, reducing supply current to 100µA. Critically, outputs remain high-Z even without Termpwr applied. With only 6pF channel capacitance in this mode, the UC5608DWP prevents bus transients during connector mating - enabling safe insertion/removal per SCSI-2 hot-plug specifications.

What thermal considerations apply to the UC5608DWP in continuous operation?

The UC5608DWP is rated for continuous 2W operation using its DWP SOIC package's dedicated heatsink pins (7, 8, 9, 20, 21, 22). It incorporates thermal shutdown at 170°C with 10°C hysteresis to prevent damage during overload. For sustained full-load use, PCB copper area connected to heatsink pins and airflow must meet TI's thermal guidelines. The UC5608DWP's low thermal resistance design allows reliable operation at −55°C to +150°C ambient - essential for industrial storage enclosures.

Is the UC5608DWP pin-compatible with earlier Unitrode SCSI terminators?

Yes - the UC5608DWP is explicitly specified as pin-for-pin compatible with the UC5601 and UC5602 18-line active terminators. Its DWP package matches the SOIC-28 footprint, pin numbering, and signal assignments of those predecessors. However, the UC5608DWP removes low-side clamps and increases sinking current from 20mA to 200mA. So while PCB layout remains identical, firmware or system-level logic relying on clamping behavior must be verified before substituting UC5608DWP for UC5601/UC5602.