CY74FCT257T

QUAD 2-INPUT MULTIPLEXER

WITH 3-STATE OUTPUTS

SCCS019D – MAY 1994 – REVISED NOVEMBER 2001

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POST OFFICE BOX 655303

With FCT and F Logic

Equivalent FCT Functions

Significantly Improved Noise

Characteristics

Operation

Output Logic Levels

– 2000-V Human-Body Model (A114-A)

– 200-V Machine Model (A115-A)

– 1000-V Charged-Device Model (C101)

32-mA Output Source Current

description

The CY74FCT257T has four identical two-input multiplexers that select four bits of data from two sources under

selected when S is high. Data at the output is noninverted.

The CY74FCT257T is a logic implementation of a four-pole, two-position switch, where the position of the switch

is determined by the logic levels at S. Outputs are in the high-impedance state when the output-enable (OE)

input is high.

All but one device must be in the high-impedance state to avoid currents exceeding the maximum ratings if

outputs are tied together. OE inputs must ensure that there is no overlap when outputs of 3-state devices are

tied together.

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

PIN DESCRIPTION

NAME

DESCRIPTION

I

Data inputs

S

Common data-select input

OE

Output-enable input (active low)

Y

Data outputs

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.

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S

GND

OE

Q OR SO PACKAGE

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