SN54HC191, SN74HC191

4BIT SYNCHRONOUS UP/DOWN BINARY COUNTERS

SCLS121D − DECEMBER 1982 − REVISED OCTOBER 2003

5

POST OFFICE BOX 655303

−0.5 V to 7 V

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

±20 mA

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

±20 mA

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

±25 mA

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

±50 mA

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

Package thermal impedance,

73

°C/W

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

N package

67

°C/W

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

NS package

64

°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. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.

2. The package thermal impedance is calculated in accordance with JESD 51-7.

recommended operating conditions (see Note 3)

SN54HC191

SN74HC191

UNIT

MIN

NOM

MAX

MIN

NOM

MAX

UNIT

VCC

Supply voltage

2

5

6

2

5

6

V

VCC = 2 V

1.5

1.5

VIH

High-level input voltage

VCC = 4.5 V

3.15

3.15

V

VIH

High-level input voltage

VCC = 6 V

4.2

4.2

V

VCC = 2 V

0.5

0.5

VIL

Low-level input voltage

VCC = 4.5 V

1.35

1.35

V

VIL

Low-level input voltage

VCC = 6 V

1.8

1.8

V

VI

Input voltage

0

VCC

0

VCC

V

VO

Output voltage

0

VCC

0

VCC

V

VCC = 2 V

1000

1000

∆t/∆v‡ Input transition rise/fall time

VCC = 4.5 V

500

500

ns

∆t/∆v‡ Input transition rise/fall time

VCC = 6 V

400

400

ns

TA

Operating free-air temperature

−55

125

−40

85

°C

NOTE 3: All unused inputs of the device must be held at VCC or GND to ensure proper device operation. Refer to the TI application report,

Implications of Slow or Floating CMOS Inputs, literature number SCBA004.

‡ If this device is used in the threshold region (from VILmax = 0.5 V to VIHmin = 1.5 V), there is a potential to go into the wrong state from induced

grounding, causing double clocking. Operating with the inputs at tt = 1000 ns and VCC = 2 V does not damage the device; however, functionally,

the CLK inputs are not ensured while in the shift, count, or toggle operating modes.