SN74ACT7806

256

× 18

STROBED FIRST-IN, FIRST-OUT MEMORY

SCAS438C – APRIL 1992 – REVISED APRIL 1998

2

POST OFFICE BOX 655303

description (continued)

A low level on the reset (RESET) input resets the internal stack pointers and sets FULL high, HF low, and

EMPTY low. The Q outputs are not reset to any specific logic level. The FIFO must be reset upon power up.The

first word loaded into empty memory causes EMPTY to go high and the data to appear on the Q outputs. It is

important to note that the first word does not have to be unloaded. The data outputs are noninverting with respect

to the data inputs and are in the high-impedance state when the output-enable (OE) input is high.

The SN74ACT7806 is characterized for operation from 0

°C to 70°C.

0

21

D0

20

D1

19

D2

18

D3

17

D4

16

D5

15

D6

14

D7

12

D8

Q0

33

0

Q1

34

Q2

36

Q3

37

Q4

38

28

FULL

HF

22

HALF-FULL

AF/AE

24

ALMOST FULL/EMPTY

29

EMPTY

Q5

40

Q6

41

Q7

42

Q8

43

Data

1

Φ

FIFO 256

× 18

SN74ACT7806

11

D9

9

D10

8

D11

7

D12

6

D13

5

D14

4

D15

3

D16

17

2

D17

Q9

45

Q10

46

Q11

47

Q12

48

Q13

49

Q14

51

Q15

53

Q16

54

Q17

55

17

RESET

OE

PEN

RESET

1

25

LDCK

LDCK

Data

PROGRAM ENABLE

23

EN1

56

32

UNCK

UNCK

EMPTY

FULL

† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.