1

Data sheet acquired from Harris Semiconductor

SCHS142

September 1997

Features

• Overriding Reset Terminates Output Pulse

• Triggering From the Leading or Trailing Edge

• Q and Q Buffered Outputs

• Separate Resets

• Wide Range of Output-Pulse Widths

• Schmitt Trigger on Both A and B Inputs

• Fanout (Over Temperature Range)

- Standard Outputs . . . . . . . . . . . . . . . 10 LSTTL Loads

- Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads

• Balanced Propagation Delay and Transition Times

• Significant Power Reduction Compared to LSTTL

Logic ICs

• HC Types

- 2V to 6V Operation

• HCT Types

- 4.5V to 5.5V Operation

- Direct LSTTL Input Logic Compatibility,

Pinout

CD74HC123, CD74HCT123, CD74HC423, CD74HCT423

(PDIP, SOIC)

TOP VIEW

Description

The Harris CD74HC123, CD74HCT123, CD74HC423 and

CD74HCT423 are dual monostable multivibrators with

resets. They are all retriggerable and differ only in that the

123 types can be triggered by a negative to positive reset

pulse; whereas the 423 types do not have this feature. An

the timing and the accuracy for the circuit. Adjustment of Rx

the Q and Q terminals. Pulse triggering on the A and B

inputs occur at a particular voltage level and is not related to

the rise and fall times of the trigger pulses.

Once triggered, the output pulse width may be extended by

retriggering inputs A and B. The output pulse can be

terminated by a LOW level on the Reset (R) pin. Trailing

edge triggering (A) and leading edge triggering (B) inputs

are provided for triggering from either edge of the input

pulse. If either Mono is not used each input on the unused

device (A, B, and R) must be terminated high or low.

The minimum value of external resistance, Rx is typically 5k

Ω.

14

15

16

9

13

12

11

10

1

2

3

4

5

7

6

8

1A

1B

1R

1Q

2Q

GND

1Q

2Q

2R

2B

2A

Ordering Information

PART NUMBER

PACKAGE

PKG.

NO.

CD74HC123E

-55 to 125

16 Ld PDIP

E16.3

CD74HCT123E

-55 to 125

16 Ld PDIP

E16.3

CD74HC423E

-55 to 125

16 Ld PDIP

E16.3

CD74HCT423E

-55 to 125

16 Ld PDIP

E16.3

CD74HC123M

-55 to 125

16 Ld SOIC

M16.15

CD74HCT123M

-55 to 125

16 Ld SOIC

M16.15

CD74HC423M

-55 to 125

16 Ld SOIC

M16.15

CD74HCT423M

-55 to 125

16 Ld SOIC

M16.15

NOTES:

1. When ordering, use the entire part number. Add the suffix 96 to

obtain the variant in the tape and reel.

2. Wafer or die for this part number is available which meets all elec-

trical specifications. Please contact your local sales office or

Harris customer service for ordering information.

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

Copyright

File Number

1708.1

CD74HC123, CD74HCT123,

CD74HC423, CD74HCT423

High Speed CMOS Logic Dual Retriggerable

Monostable Multivibrators with Resets

[ /Title

(CD74

HC123

,

CD74

HCT12

3,

CD74

HC423

,

CD74

HCT42

3)

/Sub-

ject

(High

Speed