SCAS745A − DECEMBER 2003 − REVISED APRIL 2004
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
DControlled Baseline
− One Assembly/Test Site, One Fabrication
Site
DEnhanced Diminishing Manufacturing
Sources (DMS) Support
DEnhanced Product-Change Notification
DQualification Pedigree†
DMembers of the Texas Instruments
SCOPE Family of Testability Products
DMembers of the Texas Instruments
Widebus Family
DState-of-the-Art 3.3-V ABT Design Supports
Mixed-Mode Signal Operation (5-V Input
and Output Voltages With 3.3-V VCC)
DSupport Unregulated Battery Operation
Down to 2.7 V
†Component qualification in accordance with JEDEC and industry
standards to ensure reliable operation over an extended
temperature range. This includes, but is not limited to, Highly
Accelerated Stress Test (HAST) or biased 85/85, temperature
cycle, autoclave or unbiased HAST, electromigration, bond
intermetallic life, and mold compound life. Such qualification
testing should not be viewed as justifying use of this component
beyond specified performance and environmental limits.
DInclude D-Type Flip-Flops and Control
Circuitry to Provide Multiplexed
Transmission of Stored and Real-Time Data
DBus Hold on Data Inputs Eliminates the
Need for External Pullup/Pulldown
Resistors
DB-Port Outputs of SN74LVTH182646A
Devices Have Equivalent 25-Ω Series
Resistors, So No External Resistors Are
Required
DCompatible With IEEE Std 1149.1-1990
(JTAG) Test Access Port and
Boundary-Scan Architecture
DSCOPE Instruction Set
− IEEE Std 1149.1-1990 Required
Instructions and Optional CLAMP and
HIGHZ
− Parallel-Signature Analysis at Inputs
− Pseudorandom Pattern Generation From
Outputs
− Sample Inputs/Toggle Outputs
− Binary Count From Outputs
− Device Identification
− Even-Parity Opcodes
description/ordering information
The SN74LVTH18646A and SN74LVTH182646A scan test devices, with 18-bit bus transceivers and registers,
are members of the Texas Instruments (TI) SCOPE testability integrated-circuit family. This family of devices
supports IEEE Std 1149.1-1990 boundary scan to facilitate testing of complex circuit board assemblies. Scan
access to the test circuitry is accomplished via the 4-wire test access port (TAP) interface.
Additionally, these devices are designed specifically for low-voltage (3.3-V) VCC operation, but with the
capability to provide a TTL interface to a 5-V system environment.
In the normal mode, these devices are 18-bit bus transceivers and registers that allow for multiplexed
transmission of data directly from the input bus or from the internal registers. They can be used either as two
9-bit transceivers or one 18-bit transceiver. The test circuitry can be activated by the TAP to take snapshot
samples of the data appearing at the device pins or to perform a self test on the boundary-test cells. Activating
the TAP in the normal mode does not affect the functional operation of the SCOPE bus transceivers
and registers.
ORDERING INFORMATION
TAPACKAGE‡ORDERABLE
PART NUMBER TOP-SIDE
MARKING
LQFP − PM Tape and reel 8V18646AIPMREP LH18646AEP
−40°C to 85°CLQFP − PM Tape and reel 8V182646AIPMREP§
‡Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available
at www.ti.com/sc/package.
§Product Preview
Copyright 2004, Texas Instruments Incorporated
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SCOPE and Widebus are trademarks of Texas Instruments.