September 1993

23

Philips Semiconductors

Product specification

4-Bit x 64-word FIFO register; 3-state

74HC/HCT7403

Note to Fig.19

This circuit is only required if the SI input is constantly held HIGH, when the FIFO is empty and the automatic shift-in

cycles are started or if SO output is constantly held HIGH, when the FIFO is full and the automatic shift-out cycles are

started (see Figs 7 and 10).

Fig.19 Expanded FIFO for increased word length.

handbook, full pagewidth

MGA683

DIR

OE

SI

DOR

SO

MR

Dn

Qn

4

7403

DIR

OE

SI

DOR

SO

MR

7403

Dn

Qn

SI

MR

OE

SO

composite

DOR

composite

DIR

4

4

4

DQ

CP

R

74

Q

DQ

CP

Q

D

Q

CP

74

Q

D

Q

CP

Q R