MC74HC393A

http://onsemi.com

5

PIN DESCRIPTIONS

INPUTS

Clock (Pins 1, 13)

Clock input. The internal flip–flops are toggled and the

counter state advances on high–to–low transitions of the

clock input.

CONTROL INPUTS

Reset (Pins 2, 12)

Active–high, asynchronous reset. A separate reset is

provided for each counter. A high at the Reset input prevents

counting and forces all four outputs low.

OUTPUTS

Q1, Q2, Q3, Q4 (Pins 3, 4, 5, 6, 8, 9, 10, 11)

Parallel binary outputs Q4 is the most significant bit.

SWITCHING WAVEFORMS

tPHL

VCC

GND

VCC

GND

50%

50%

50%

trec

CLOCK

Q

RESET

Figure 1.

Figure 2.

Figure 3. Test Circuit

Q1

Q2

Q3

Q4

CLOCK

RESET

1, 13

2, 12

3, 11

4, 10

5, 9

6, 8

EXPANDED LOGIC DIAGRAM

*Includes all probe and jig capacitance

CL*

TEST

POINT

DEVICE

UNDER

TEST

OUTPUT

CLOCK

Q

90%

90%

50%

10%

tf

tr

VCC

GND

tw

1/fmax

tPLH

tPHL

90%

50%

10%

tTLH

tTHL

C

DQ

tw

Q

C

DQ

Q

C

DQ

Q

C

DQ

Q