CY74FCT2543T

8-BIT LATCHED TRANSCEIVER

WITH 3-STATE OUTPUTS

SCCS042C – SEPTEMBER 1994 – REVISED NOVEMBER 2001

1

POST OFFICE BOX 655303

and F Logic

Transmission-Line Reflection Noise

of Equivalent FCT Functions

Significantly Improved Noise

Characteristics

Operation

Output Logic Levels

15-mA Output Source Current

Direction

– 2000-V Human-Body Model (A114-A)

– 200-V Machine Model (A115-A)

– 1000-V Charged-Device Model (C101)

description

The CY74FCT2543T octal latched transceiver contains two sets of eight D-type latches. Separate latch enable

(LEAB, LEBA) and output enable (OEAB, OEBA) inputs permit each latch set to have independent control of

inputting and outputting in either direction of data flow. For example, for data flow from A to B, the A-to-B enable

(CEAB) input must be low to enter data from A or to take data from B, as indicated in the function table. With

CEAB low, a low signal on the A-to-B latch enable (LEAB) input makes the A-to-B latches transparent; a

subsequent low-to-high transition of LEAB puts the A latches in the storage mode and their outputs no longer

change with the A inputs. With CEAB and OEAB both low, the 3-state B output buffers are active and reflect

data present at the output of the A latches. Control of data from B to A is similar, but uses CEAB, LEAB, and

OEAB inputs. On-chip termination resistors at the outputs reduce system noise caused by reflections. The

CY74FCT2543T can replace the CY74FCT543T to reduce noise in an existing design.

preventing damaging current backflow through the device when it is powered down.

Copyright

 2001, Texas Instruments Incorporated

PRODUCTION DATA information is 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.

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.

Q OR SO PACKAGE

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LEBA

OEBA

CEAB

GND

CEBA

LEAB

OEAB