CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper I.C. Handling Procedures.

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SEMICONDUCT OR

CD54AC191/3A

CD54ACT191/3A

Presettable Synchronous

4-Bit Binary Up/Down Counters

Functional Diagram

ACT INPUT LOAD TABLE

INPUT

UNIT LOAD (NOTE 1)

P0 - P3, PL

0.75

CL, U/D, CE

0.85

NOTE:

1. Unit load is

∆I

ASYN. PARALLEL

CLOCK

UP/DOWN

11

14

5

15

1

10

9

3

2

6

7

12

Q0

Q1

Q2

Q3

TERMINAL

P0

P1

P2

P3

BINARY PRESET

COUNT

4

13

RIPPLE CLOCK

ENABLE

LOAD ENABLE

COUNT

BINARY

OUTPUTS

June 1997

File Number

3896

Description

The CD54AC191/3A and CD54ACT191/3A are asynchro-

nously presettable binary up/down synchronous counters

that utilize the Harris Advanced CMOS Logic technology.

Presetting the counter to the number on preset data inputs

(P0-P3) is accomplished by setting LOW the asynchronous

parallel load input (PL). Counting occurs when PL is HIGH.

Count Enable (CE) is LOW, and the Up/Down (U/D) input is

either LOW for up-counting or HIGH for down-counting. The

counter is incremented or decremented synchronously with

the LOW-to-HIGH transition of the clock.

When an overflow or underflow of the counter occurs, the

Terminal Count (TC) output, which is LOW during counting,

goes HIGH and remains HIGH for one clock cycle. This

output can be used for look-ahead carry in high-speed

cascading. The TC output also initiates the Ripple Clock

(RC) output which, normally HIGH, goes LOW and remains

LOW for the low-level portion of the clock pulse. These

counters can be cascaded using the Ripple Count output.

The CD54AC191/3A and CD54ACT191/3A are supplied in

16-lead dual-in-line ceramic packages (F suffix).

Absolute Maximum Ratings

For Up to 4 Outputs Per Device, Add

±25mA For Each

Additional Output

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .±100mA

Lead Temperature (During Soldering)

At Distance 1/16in.

± 1/32in. (1.59mm ± 0.79mm)

Unit Inserted Into a PC Board (Min Thickness 1/16in., 1.59mm)

CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation

of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.

Recommended Operating Conditions

Unless Otherwise Specified, All Voltages Referenced to GND

CD54AC Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5V to 5.5V

CD54ACT Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.5V to 5.5V

Input Rise and Fall Slew Rate, dt/dv

at 1.5V to 3V (AC Types) . . . . . . . . . . . . . . . . . . . 0ns/V to 50ns/V

at 3.6V to 5.5V (AC Types) . . . . . . . . . . . . . . . . . 0ns/V to 20ns/V

at 4.5V to 5.5V (AC Types) . . . . . . . . . . . . . . . . . 0ns/V to 10ns/V

COMING SOON!

COMPLETE DATA SHEET