SN54LVTH18652A Datasheet, PDF (1/38 Pages) Texas Instruments – 3.3-V ABT SCAN TEST DEVICES WITH 18-BIT TRANSCEIVERS AND REGISTERS

SN54LVTH18652A, SN54LVTH182652A, SN74LVTH18652A, SN74LVTH182652A
3.3-V ABT SCAN TEST DEVICES
WITH 18-BIT TRANSCEIVERS AND REGISTERS
SCBS312C – MARCH 1994 – REVISED JUNE 1997
D Members of the Texas Instruments
SCOPE ™ Family of Testability Products
D Members of the Texas Instruments
Widebus ™ Family
D State-of-the-Art 3.3-V ABT Design Supports
Mixed-Mode Signal Operation (5-V Input
and Output Voltages With 3.3-V V_CC)
D Support Unregulated Battery Operation
Down to 2.7 V
D Include D-Type Flip-Flops and Control
Circuitry to Provide Multiplexed
Transmission of Stored and Real-Time Data
D Bus Hold on Data Inputs Eliminates the
Need for External Pullup/Pulldown
Resistors
D B-Port Outputs of ’LVTH182652A Devices
Have Equivalent 25-Ω Series Resistors, So
No External Resistors Are Required
D Compatible With the IEEE Std 1149.1-1990
(JTAG) Test Access Port and
Boundary-Scan Architecture
D SCOPE Instruction Set
– IEEE Std 1149.1-1990 Required
Instructions and Optional CLAMP and
HIGHZ
– Parallel-Signature Analysis at Inputs
– Pseudo-Random Pattern Generation
From Outputs
– Sample Inputs/Toggle Outputs
– Binary Count From Outputs
– Device Identification
– Even-Parity Opcodes
D Packaged in 64-Pin Plastic Thin Quad Flat
(PM) Packages Using 0.5-mm
Center-to-Center Spacings and 68-Pin
Ceramic Quad Flat (HV) Packages Using
25-mil Center-to-Center Spacings
description
The ’LVTH18652A and ’LVTH182652A 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) V_CC 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.
Data flow in each direction is controlled by clock (CLKAB and CLKBA), select (SAB and SBA), and
output-enable (OEAB and OEBA) inputs. For A-to-B data flow, data on the A bus is clocked into the associated
registers on the low-to-high transition of CLKAB. When SAB is low, real-time A data is selected for presentation
to the B bus (transparent mode). When SAB is high, stored A data is selected for presentation to the B bus
(registered mode). When OEAB is high, the B outputs are active. When OEAB is low, the B outputs are in the
high-impedance state.
Control for B-to-A data flow is similar to that for A-to-B data flow but uses CLKBA, SBA, and OEBA inputs. Since
the OEBA input is active-low, the A outputs are active when OEBA is low and are in the high-impedance state
when OEBA is high. Figure 1 illustrates the four fundamental bus-management functions that can be performed
with the ’LVTH18652A and ’LVTH182652A.
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 Incorporated.
UNLESS OTHERWISE NOTED this document contains PRODUCTION
DATA information current as of publication date. Products conform to
specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all
parameters.
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Copyright © 1997, Texas Instruments Incorporated
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