PIN DESCRIPTIONS

PIN

PIN TYPE *

DESCRIPTION

I

Data Inputs, LH5481

O/Z

Data Outputs, LH5481

I

Data Inputs, LH5491

O

Data Outputs, LH5491

SI

I

Shift In

SO

I

Shift Out

IR

O

Input Ready

OR

O

Output Ready

* I = Input, O = Output, Z = High-Impedance, V = Power Voltage Level

PIN

PIN TYPE *

DESCRIPTION

HF

O

Half-Full Flag

AFE

O

Almost-Full / Almost-

Empty

MR

I

Master Reset

OE

I

Output Enable

(LH5481 only)

V

Positive Power Supply

V

Ground

5481-3

WRITE POINTER

WRITE MULTIPLEXER

MEMORY ARRAY

READ MULTIPLEXER

READ POINTER

INPUT

CONTROL

LOGIC

DATA IN

MASTER

RESET

SI

IR

MR

ALMOST-FULL/

ALMOST-EMPTY

HALF-FULL

DATA OUT

OUTPUT

CONTROL

LOGIC

AFE

HF

OR

SO

(LH5491)

OE

(LH5481)

.

.

.

.

.

.

Figure 3. LH5481/91 Block Diagram

LH5481/91

64

× 8 / 64 × 9 FIFO

2