CY54FCT646T, CY74FCT646T

8-BIT REGISTERED TRANSCEIVERS

WITH 3-STATE OUTPUTS

SCCS031A – JULY 1994 – REVISED OCTOBER 2001

1

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

D Function, Pinout, and Drive Compatible

With FCT and F Logic

D Reduced VOH (Typically = 3.3 V) Versions

of Equivalent FCT Functions

D Edge-Rate Control Circuitry for

Significantly Improved Noise

Characteristics

D Ioff Supports Partial-Power-Down Mode

Operation

D Matched Rise and Fall Times

D Fully Compatible With TTL Input and

Output Logic Levels

D ESD Protection Exceeds JESD 22

– 2000-V Human-Body Model (A114-A)

– 200-V Machine Model (A115-A)

– 1000-V Charged-Device Model (C101)

D Independent Register for A and B Buses

D CY54FCT646T

– 48-mA Output Sink Current

– 12-mA Output Source Current

D CY74FCT646T

– 64-mA Output Sink Current

– 32-mA Output Source Current

D 3-State Outputs

description

The

’FCT646T

devices

consist

of

a

bus

transceiver circuit with 3-state, D-type flip-flops,

and control circuitry arranged for multiplexed

transmission of data directly from the input bus or

from the internal registers. Data on the A or B bus

is clocked into the registers as the appropriate

clock pin goes to a high logic level. Output-enable (G) and direction (DIR) inputs control the transceiver function.

In the transceiver mode,data present at the high-impedance port can be stored in either the A or B register, or

in both. Select controls (SAB, SBA) can multiplex stored and real-time (transparent mode) data. DIR determines

which bus receives data when G is low. In the isolation mode (G is high), A data can be stored in the B register

and/or B data can be stored in the A register.

These devices are fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the

outputs, 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.

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8

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12

24

23

22

21

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19

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16

15

14

13

CPAB

SAB

DIR

A1

A2

A3

A4

A5

A6

A7

A8

GND

VCC

CPBA

SBA

G

B1

B2

B3

B4

B5

B6

B7

B8

32 1 28 27

12 13

5

6

7

8

9

10

11

25

24

23

22

21

20

19

G

B1

B2

NC

B3

B4

B5

A1

A2

A3

NC

A4

A5

A6

426

14 15 16 17 18

NC – No internal connection

CY54FCT646T ...D PACKAGE

CY74FCT646T ...Q OR SO PACKAGE

(TOP VIEW)

CY54FCT646T . . . L PACKAGE

(TOP VIEW)

On products compliant to MIL-PRF-38535, all parameters are tested

unless otherwise noted. On all other products, production

processing does not necessarily include testing of all parameters.