1

PS8548

07/31/01

12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789012123456789012

12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789012123456789012

12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789012123456789012

PI74AVC+16821

2.5V 20-Bit Bus Interface

Flip-Flop with 3-State Outputs

Logic Block Diagram

Product Features

• PI74AVC

• True ±24mA Balanced Drive @ 3.3V

• 3.6V I/O Tolerant Inputs and Outputs

• All outputs contain a patented DDC

(Dynamic Drive Control) circuit that reduces noise

without degrading propagation delay

• Industrial operation: –40°C to +85°C

• Available Packages:

– 56-pin 240 mil wide plastic TSSOP (A)

– 56-pin 173 mil wide plastic TVSOP (K)

Description

Pericom Semiconductor’s PI74AVC+ series of logic circuits are

produced using the Company’s advanced submicron CMOS

technology, achieving industry leading speed.

ThePI74AVC+16821isa20-bit businterfaceflip-flopdesignedfor

or one 20-bit flip-flop. The 20 flip-flops are edge-triggered D-type

flip-flops. On the positive transition of the clock (CLK) input, the

device provides true data at the Q outputs.

A buffered output-enable (OE) input can be used to place the ten

outputsineitheranormallogicstate(HIGHorLOWlevel)orahigh-

impedance state. In the high-impedance state, the outputs neither

load nor drive the bus lines significantly. The high-impedance state

and increased drive provide the capacity to drive bus lines without

the need for interface or pullup components.

OE does not affect the internal operation of the flip-flops. Old data

can be retained or new data can be entered while the outputs are in

the high-impedance state.

To ensure the high-impedance state during power up or power

minimum value of the resistor is determined by the current sinking

capability of the driver.

1

OE

1

D

1CLK

TO 9 OTHER CHANNELS

1

1

56

55

2

One of Ten

Channels

2

OE

1

D

2CLK

TO 9 OTHER CHANNELS

28

29

42

15

One of Ten

Channels