SN74ALS232B

16

× 4 ASYNCHRONOUS FIRST-IN, FIRST-OUT MEMORY

SCAS251B – FEBRUARY 1989 – REVISED APRIL 1998

5

POST OFFICE BOX 655303

recommended operating conditions (see Note 3)

MIN

NOM

MAX

UNIT

VCC

Supply voltage

4.5

5

5.5

V

VIH

High-level input voltage

2

V

VIL

Low-level input voltage

0.8

V

IOH

High level output current

Q outputs

–2.6

mA

IOH

High-level output current

FULL, EMPTY

–0.4

mA

IOL

Low level output current

Q outputs

24

mA

IOL

Low-level output current

FULL, EMPTY

8

mA

TA

Operating free-air temperature

0

70

°C

NOTE 3: To ensure proper operation of this high-speed FIFO device, it is necessary to provide a clean signal to the LDCK and UNCK clock inputs.

Any excessive noise or glitching on the clock inputs that violates limits for maximum VIL, minimum VIH, or minimum pulse duration can

cause a false clock or improper operation of the internal read and write pointers.

electrical characteristics over recommended operating free-air temperature range (unless

otherwise noted)

PARAMETER

TEST CONDITIONS

MIN

TYP†

MAX

UNIT

VIK

VCC = 4.5 V,

II = –18 mA

–1.2

V

VOH

Q outputs

VCC = 4.5 V,

IOH = –2.6 mA

2.4

3.2

V

VOH

FULL, EMPTY

VCC = 4.5 V to 5.5 V,

IOH = –0.4 mA

VCC–2

V

Q outputs

VCC =4 5V

IOL = 12 mA

0.25

0.4

VOL

Q outputs

VCC = 4.5 V

IOL = 24 mA

0.35

0.5

V

VOL

FULL EMPTY

VCC =4 5V

IOL = 4 mA

0.25

0.4

V

FULL, EMPTY

VCC = 4.5 V

IOL = 8 mA

0.35

0.5

IOZH

VCC = 5.5 V,

VO = 2.7 V

20

µA

IOZL

VCC = 5.5 V,

VO = 0.4 V

–20

µA

II

VCC = 5.5 V,

VI = 7 V

0.1

mA

IIH

VCC = 5.5 V,

VI = 2.7 V

20

µA

IIL

VCC = 5.5 V,

VI = 0.4 V

–0.2

mA

IO‡

VCC = 5.5 V,

VO = 2.25 V

–30

–112

mA

ICC

VCC = 5.5 V

80

125

mA

† All typical values are at VCC = 5 V, TA = 25°C.

‡ The output conditions have been chosen to produce a current that closely approximates one-half of the true short-circuit output current, IOS.