September 1993

22

Philips Semiconductors

Product specification

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

74HC/HCT7403

Note to Fig.18

The “7403” is easily expanded to increase word length. Composite DIR and DOR flags are formed with the addition of

an AND gate. The basic operation and timing are identical to a single FIFO, with the exception of an added gate delay

on the flags.

Fig.18 Expanded FIFO for increased word length; 64 words x 10 bits.

handbook, full pagewidth

MGA678

DIR

OE

SI

DOR

SO

MR

Dn

Qn

4

4

7403

DIR

OE

SI

DOR

SO

MR

7403

Dn

Qn

4

4

DATA INPUT

COMPOSITE

DIR

FLAG

SI

MR

OE

SO

DATA OUTPUT

COMPOSITE

DOR

FLAG

DATA INPUT

DATA OUTPUT