SN74LS228

16

× 4 SYNCHRONOUS FIRST-IN, FIRST-OUT MEMORY

WITH OPEN-COLLECTOR OUTPUTS

SDLS024 – JANUARY 1991 – REVISED SEPTEMBER 1993

POST OFFICE BOX 655303

10–6

recommended operating conditions (see Note 2)

MIN

NOM

MAX

UNIT

VCC

Supply voltage

4.75

5

5.25

V

VIH

High-level input voltage

2

V

VIL

Low-level input voltage

0.8

V

VOH

High-level output voltage

Q outputs

5.5

V

IOH

High-level output current

IR, OR

– 0.4

mA

IOL

Low level output current

Q outputs

24

mA

IOL

Low-level output current

IR, OR

8

mA

LDCK high

60

LDCK low

15

tw

Pulse duration

UNCK low

30

ns

UNCK high

30

CLR low

20

Data to LDCK

↓

50

tsu

Setup time

LDCK

↓ before UNCK↓

50

ns

UNCK

↑ before LDCK↑

50

th

Hold time

Data from LDCK

↓

0

ns

TA

Operating free-air temperature

0

70

°C

NOTE 2: 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 the VIL, VIH, or minimum pulse duration limits 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 = 4.75 V,

II = – 18 mA

– 1.5

V

IOH

Q outputs

VCC = 4.75 V,

VOH = 5.5 V

0.1

mA

VOH

IR, OR

VCC = 4.75 V,

IOH = – 0.4 mA

2.7

3.4

V

Q outputs

VCC = 4 75 V

IOL = 12 mA

0.25

0.4

VOL

Q outputs

VCC = 4.75 V

IOL = 24 mA

0.35

0.5

V

VOL

IR OR

VCC = 4 75 V

IOL = 4 mA

0.25

0.4

V

IR, OR

VCC = 4.75 V

IOL = 8 mA

0.35

0.5

IOZH

Q outputs

VCC = 5.25 V,

VO = 2.7 V

20

µA

IOZL

Q outputs

VCC = 5.25 V,

VO = 0.4 V

–20

µA

II

VCC = 5.25 V,

VI = 7 V

0.1

mA

IIH

VCC = 5.25 V,

VI = 2.7 V

20

µA

IIL

VCC = 5.25 V,

VI = 0.4 V

– 0.4

mA

IOS‡

IR, OR

VCC = 5.25 V

–20

– 100

mA

Outputs high

84

135

ICC

VCC = 5.25 V

Outputs low

87

155

mA

Outputs disabled

89

155

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

‡ Not more than one output should be shorted at a time, and duration of the short circuit should not exceed one second.