Functional Description

The ’AC/ACT399 is a high-speed quad 2-port register. It se-

lects four bits of data from either of two sources (Ports) un-

der control of a common Select input (S). The selected data

is transferred to a 4-bit output register synchronous with the

LOW-to-HIGH transition of the Clock input (CP). The 4-bit

D-type output register is fully edge-triggered. The Data in-

puts (I

time prior to and hold time after the LOW-to-HIGH transition

of the Clock input for predictable operation.

Function Table

Inputs

Outputs

SI

0

I

1

CP

Q

Q

LL

X

N

LH

LH

X

N

HL

HX

L

N

LH

HX

H

N

HL

H = HIGH Voltage Level

L = LOW Voltage Level

X = Immaterial

Logic Diagram

DS100356-4

Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.

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