16-Bit Registered Transceivers

CY74FCT16646T

CY74FCT162646T

SCCS060 - August 1994 - Revised March 2000

Data sheet acquired from Cypress Semiconductor Corporation.

Data sheet modified to remove devices not offered.

Copyright

Features

• FCT-E speed at 3.8 ns

• Power-off disable outputs permits live insertion

• Edge-rate control circuitry for significantly improved

noise characteristics

• Typical output skew < 250 ps

• ESD > 2000V

• TSSOP (19.6-mil pitch) and SSOP (25-mil pitch)

packages

• Industrial temperature range of

−40˚C to +85˚C

CY74FCT16646T Features:

• 64 mA sink current, 32 mA source current

CY74FCT162646T Features:

• Balanced 24 mA output drivers

• Reduced system switching noise

Functional Description

The

CY74FCT16646T

and

CY74FCT162646T

16-bit

transceivers are three-state, D-type registers, 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 will be clocked into the registers as the appropriate

clock pin goes to a HIGH logic level. Output Enable (OE) and

direction pins (DIR) are provided to control the transceiver

function. In the transceiver mode, data present at the high

impedance port may be stored in either the A or B register, or

in both. The select controls can multiplex stored and real-time

(transparent mode) data. The direction control determines

which bus will receive data when the Output Enable (OE) is

Active LOW. In the isolation mode (Output Enable (OE) HIGH),

A data may be stored in the B register and/or B data may be

stored in the A register. The output buffers are designed with

a power-off disable feature that allows live insertion of boards.

The

CY74FCT16646T

is

ideally

suited

for

driving

high-capacitance loads and low-impedance backplanes.

The CY74FCT162646T has 24-mA balanced output drivers

with current limiting resistors in the outputs. This reduces the

need for external terminating resistors and provides for

minimal undershoot and reduced ground bounce. The

CY74FCT162646T is ideal for driving transmission lines.

Logic Block Diagrams

FCT16646-1

C

D

1B1

C

D

1A1

TO 7 OTHER CHANNELS

1SAB

1CLKAB

1CLKBA

1DIR

1SBA

1OE

B REG

A REG

C

D

2B1

C

D

2A1

2SAB

2CLKAB

2CLKBA

2DIR

2SBA

2OE

B REG

FCT16646-2

TO 7 OTHER CHANNELS

A REG