SN74ALS232B

16

× 4 ASYNCHRONOUS FIRST-IN, FIRST-OUT MEMORY

SCAS251B – FEBRUARY 1989 – REVISED APRIL 1998

4

POST OFFICE BOX 655303

timing diagram

Invalid

Invalid

Word 1

Word 1

Word 2 Word 3

RST

LDCK

D0–D3

UNCK

Q0–Q3

EMPTY

FULL

W1

W2

W3

Don’t Care

W1

W2

W15 W16

Word 2 Word 3 Word 4

Initialize

Pointers

Load

W1

Unload

W2

Empty

Full

–0.5 V to 7 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–0.5 V to 7 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Voltage range applied to a disabled 3-state output

–0.5 V to 5.5 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Package thermal impedance,

105

°C/W

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FN package

83

°C/W

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

N package

78

°C/W

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–65

°C to 150°C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. This is a stress rating only, and

functional operation of the device at these or any other conditions beyond those indicated in the “recommended operating conditions” section of

this specification is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

NOTES:

1. All voltage values are with respect to GND.

2. The package thermal impedance is calculated in accordance with JESD 51, except for through-hole packages, which use a trace

length of zero.