Functional Description

The ’F398 and ’F399 are high-speed quad 2-port registers

They select four bits of data from either of two sources

(Ports) under control of a common Select input (S) The

selected data is transferred to a 4-bit output register syn-

chronous with the LOW-to-HIGH transition of the Clock in-

put (CP) The 4-bit D-type output register is fully edge-trig-

stable only a setup time prior to and hold time after the

LOW-to-HIGH transition of the Clock input for predictable

operation The ’F398 has both Q and Q outputs

Function Table

Inputs

Outputs

QQ

II

X

L

H

Ih

X

H

L

hX

I

L

H

hX

h

H

L

transition

transition

’F398 only

Logic Diagram

TLF9533 – 9

’F398 Only

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

3