Functional description

M74HC259

2

Functional description

Table 3: Truth table

Inputs

Outputs of addressed latch

Other output

Function

CLEAR

ENABLE

H

L

D

Qi0

Addressable latch

H

H

Qi0

Qi0

Memory

L

L

D

L

8-line demulitplexer

L

H

L

L

Clear all bits to "L"

D: the level at the data input

Qi0: the level before the indicated steady state input conditions where established (i = 0, 1,

……, 7)

Inputs selected

Latch addressed

C

B

A

L

L

L

Q0

L

L

H

Q1

L

H

L

Q2

L

H

H

Q3

H

L

L

Q4

H

L

H

Q5

H

H

L

Q6

H

H

H

Q7

Figure 2: Input and output equivalent circuit

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DocID001933 Rev 2