SN54LS490, SN74LS490

DUAL 4-BIT DECADE COUNTERS

SDLS125A – OCTOBER 1976 – REVISED JULY 1998

5

POST OFFICE BOX 655303

–0.5 V to 7 V

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

Clear and set-to-9 voltage

–0.5 V to 7 V

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

Clock input voltage

–0.5 V to 5.5 V

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

Package thermal impedance,

113

°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. These are stress ratings only, and

functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not

implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

NOTES:

1. Voltage values are with respect to network ground terminal.

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

length of zero.

recommended operating conditions

SN54LS490

SN74LS490

UNIT

MIN

NOM

MAX

MIN

NOM

MAX

UNIT

VCC

Supply voltage

4.5

5

5.5

4.75

5

5.25

V

IOH

High-level output current

–400

–400

µA

IOL

Low-level output current

4

8

mA

fcount

Count frequency

0

25

0

25

MHz

tw

Pulse width (any input)

20

20

ns

tsu

Clear or set-to-9 inactive-state setup time

25

↓‡

25

↓‡

ns

TA

Operating free-air temperature

–55

125

0

70

°C

‡ The arrow (

↓) indicates that the falling edge of the clock pulse is used for reference.