Texas Instruments CY74FCT2543TQCT, CY74FCT2543TQC, CY74FCT2543CTSOCT, CY74FCT2543CTSOC, CY74FCT2543CTQCT Datasheet

8-Bit Latched Transceive

r

CY74FCT2543T

SCCS042 - September 1994 - Revised March 2000

Data sheet acquired from Cypress Semiconductor Corporation.
Data sheet modified to remove devices not offered.

Copyright © 2000, Texas Instruments Incorporated

Features

• Function and pinout compatible with FCT and F logic

• FCT-C speed at 5.3 ns max.

FCT-A speed at 6.5 ns max.

• 25Ωoutputseriesresistorstoreducetransmissionline

reflection noise

• Reduced V

OH

(typically = 3.3V) versions of equivalent

FCT functions

• Edge-rate control circuitry for significantly improved

noise characteristics

• Power-off disable feature

• Matched rise and fall times

• Fully compatible with TTL input and output logic levels

• Sink current 12 mA
Source current 15 mA

• Separation controls for data flow in each direction

• Back to back latches for storage

• ESD > 2000V

• Extended commercial temp. range of –40˚C to +85˚C

Functional Description

The FCT2543T Octal Latched Tranceiver contains two sets of
eight D-type latches. Separate Latch Enable (

LEAB, LEBA)

and Output Enable (

OEAB, OEBA) permits each latch set to
have independent control of inputting and outputting in either
direction of data flow. For data flow from A to B, for example,
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 truth table.
With

CEAB LOW, a LOW signal on the A-to-B Latch Enable

(

LEAB) input makes the A-to-B latches transparent; a subse-

quent LOW-to-HIGH transition of the

LEAB signal puts the A
latches in the storage mode and their output no longer change
with the A inputs. With

CEAB and OEAB both LOW, the
three-state B output buffersare 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 have been added to the outputs to reduce
system noise caused by reflections. The FCT2543T can be
used to replace the FCT543T to reduce noise in an existing
design.

The outputs are designed with a power-off disable feature to
allow for liv e insertion of boards.

FCT2543T–1

LE

D

Q

LE

DQ

Detail A

Detail A x 7

A

0

A

2

A

1

A

3

A

4

A

6

A

5

A

7

B

0

B

2

B

1

B

3

B

4

B

6

B

5

B

7

OEBA

CEBA

LEBA

OEAB

CEAB

LEAB

FunctionalBlock Diagram Pin Configurations

1
2
3
4
5
6
7
8
9
10
11
12

16

17

18

19

20

24
23
22
21

13

14

V

CC

FCT2543T–3

15

SOIC/QSOP

Top View

LEBA

A

1

A

2

A

3

A

4

A

5

A

6

A

7

CEAB

B

1

B

2

B

3

B

4

B

5

B

6

B

7

OEAB

CEBAOEBA

A

0

GND

B

0

LEAB

CY74FCT2543T

2

Maximum Ratings

[4,5]

(Above which theuseful life may be impaired. For user guide­lines, not tested.)

Storage Temperature .....................................−65°C to +150°C

Ambient Temperature with

Power Applied..................................................−65°C to +135°C

Supply Voltage to Ground Potential..................−0.5V to +7.0V

DC Input Voltage .................................................−0.5V to +7.0V

DC Output Voltage..............................................−0.5V to +7.0V

DC Output Current (Maximum Sink Current/Pin) ......120 mA

Power Dissipation..........................................................0.5W

Static Discharge Voltage............................................>2001V

(per MIL-STD-883, Method 3015)

Pin Description

Name Description

OEAB A-to-B Output Enable Input (Active LOW)
OEBA B-to-A Output Enable Input (Active LOW)
CEAB A-to-B Enable Input (Active LOW)
CEBA B-to-A Enable Input (Active LOW)
LEAB A-to-B Latch Enable Input (Active LOW)
LEBA B-to-A Latch Enable Input (Active LOW)
A A-to-B Data Inputs or B-to-A Three-State Outputs
B B-to-A Data Inputs or A-to-B Three-State Outputs

Function Table

[1,2]

Inputs Latch Outputs

CEAB LEAB OEAB A-to-B

[3]

B

H X X Storing High Z
X H X Storing X
X X H X High Z

L L L Transparent Current A Inputs
L H L Storing Previous A Inputs

Operating Range

Range

Ambient

Temperature V

CC

Commercial −40°C to +85°C 5V ± 5%

Electrical Characteristics Over the Operating Range

Parameter Description Test Conditions Min. Typ.

[7]

Max. Unit

V

OH

Output HIGH Voltage VCC=Min., IOH=−15 mA 2.4 3.3 V

V

OL

Output LOW Voltage VCC=Min., IOL=12 mA 0.3 0.55 V

R

OUT

Output Resistance VCC=Min., IOL=12 mA 20 25 40 Ω

V

IH

Input HIGH Voltage 2.0 V

V

IL

Input LOW Voltage 0.8 V

V

H

Hysteresis

[8]

All inputs 0.2 V

V

IK

Input Clamp Diode Voltage VCC=Min., IIN=−18 mA −0.7 −1.2 V

I

IH

Input HIGH Current VCC=Max., VIN=V

CC

5 µA

I

IH

Input HIGH Current VCC=Max., VIN=2.7V ±1 µA

I

IL

Input LOW Current VCC=Max., VIN=0.5V ±1 µA

I

OZH

Off State HIGH-Level Output
Current

VCC=Max., V

OUT

=2.7V 15 µA

I

OZL

Off State LOW-Level
Output Current

VCC=Max., V

OUT

=0.5V −15 µA

I

OS

Output Short Circuit Current

[9]

VCC=Max., V

OUT

=0.0V −60 −120 −225 mA

I

OFF

Power-Off Disable VCC=0V, V

OUT

=4.5V ±1 µA

Notes:

1. H = HIGH Voltage Level. L = LOW Voltage Level. X = Don’t Care.

2. A-to-B data flow shown: B-to-A is the same, except using

CEBA, LEBA, and OEBA.

3. Before LEAB LOW-to-HIGH transition.

4. Unless otherwise noted, these limits are over the operating free-air temperature range.

5. Unused inputs must always be connected to an appropriate logic voltage level, preferably either VCC or ground.

6. T

A

is the “instant on” case temperature.