Texas Instruments Multimode SCSI 15-Line Terminator UCC5638 datasheet user manual
Summary
The UCC5638 is a highly adaptable multimode SCSI terminator designed to provide reliable signal integrity across various industry standards. It features automatic detection and seamless switching between Single Ended (SE), Low Voltage Differential (LVD), and high impedance states, supporting SPI-2 through SPI-4 architectures. This device is ideal for embedded systems engineers developing hardware that requires robust termination for complex parallel interfaces ranging from SCSI-1 to Ultra320. The provided manual details its comprehensive electrical characteristics and diverse operational modes.
Page 1 Text Content
UCC5638
Multimode SCSI 15 Line Terminator
DESCRIPTION
FEATURES
The UCC5638 Multimode SCSI Terminator provides smooth transition
Auto Selection Single Ended (SE) or
into the LVD SCSI Parallel Interface (SPI-2, SPI-3, SPI-4). It automatically
Low Voltage Differential (LVD)
Termination senses the bus, via DIFFB, and switches the termination to either single ended (SE) or low voltage differential (LVD) SCSI, dependent on which
Meets SCSI-1, SCSI-2, Ultra2 (SPI-2
type of devices are connected to the bus. The UCC5638 can not be used
LVD SCSI), Ultra3, Ultra160 (SPI-3)
on HVD, EIA485, differential SCSI bus. If the UCC5638 detects HVD
and Ultra320 (SPI-4) Standards
SCSI device, it switches to a high impedance state.
2.7V to 5.25V Operation
The Multimode terminator contains all functions required to terminate and Differential Failsafe Bias auto detect and switch modes for SPI-2, SPI-3 and SPI-4 bus architectures. Single Ended and Differential impedances and currents are trimmed for
Thermal packaging for low junction
maximum effectiveness. Fail Safe biasing is provided to insure signal integ-
temperature and better MTBF.
rity. Device/Bus type detection circuitry is integrated into the terminator to provide automatic switching of termination between single ended and LVD SCSI and high impedance for HVD SCSI. The multimode function pro- vides all the performance analog functions necessary to implement SPI-2 termination in a single monolithic device. The UCC5638 is offered in pin LQFP package for temperature range of 0°C to 70°C.
BLOCK DIAGRAM
(NOISE LOAD)
HIGH POWER
2.15V DIFFERENTIAL
REF 1.3V
1.3V DIFFSEN
LOW VOLTAGE
34DIFFB
DIFFERENTIAL
–15m A ISOURCE –5m A
SINGLE ENDED 50µA ISINK 200µA
SOURCE/SINK REGULATOR
REF L1– 1.25V
MODE ALL SWITCHES L1+
SE UP LVD DOWN SE GND SWITCH
10µA DISCNCT OPEN
36DISCNCT 56m V
3TRMPWR
SE GND SWITCH
HS/GND HS/GND 4-9 28-33
REG GND 4.7µF
UDG-98063
SLUS271B - FEBRUARY 2000 - REVISED APRIL 2001
Page Summary Contents For Texas Instruments Multimode SCSI 15-Line Terminator UCC5638 datasheet user manual
Manual Details
| Brand | Texas Instruments |
|---|---|
| Pages | 8 |
| File Size | 132.29 KB |
| Published | July 12, 2026 |
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Frequently Asked Questions
What SCSI standards does the UCC5638 support?
It supports SCSI-1, SCSI-2, Ultra2 through Ultra160 (SPI-2, SPI-3, SPI-4).
Can this terminator be used on an HVD or EIA485 bus?
No; it cannot be used on a HVD, EIA485, or any differential SCSI bus.
How does the device automatically detect termination modes?
It senses the bus via DIFFB and switches automatically between single-ended (SE) or low voltage differential (LVD) termination.
What is the recommended operating supply voltage range?
The recommended operating condition for the UCC5638 is 2.7V to 5.25V.