MOTOROLA

SEMICONDUCTOR TECHNICAL DATA

3–1

REV 6

10/95

Dual Precision

Monostable Multivibrator

(Retriggerable, Resettable)

The MC54/74HC4538A is identical in pinout to the MC14538B. The device

inputs are compatible with standard CMOS outputs; with pullup resistors,

they are compatible with LSTTL outputs.

This dual monostable multivibrator may be triggered by either the positive

or the negative edge of an input pulse, and produces a precision output

pulse over a wide range of pulse widths. Because the device has conditioned

trigger inputs, there are no trigger–input rise and fall time restrictions. The

output pulse width is determined by the external timing components, Rx and

Cx. The device has a reset function which forces the Q output low and the Q

output high, regardless of the state of the output pulse circuitry.

• Unlimited Rise and Fall Times Allowed on the Trigger Inputs

• Output Pulse is Independent of the Trigger Pulse Width

• ± 10% Guaranteed Pulse Width Variation from Part to Part (Using the

Same Test Jig)

• Output Drive Capability: 10 LSTTL Loads

• Outputs Directly Interface to CMOS, NMOS and TTL

• Operating Voltage Range: 3.0 to 6.0 V

• Low Input Current: 1.0 µA

• High Noise Immunity Characteristic of CMOS Devices

• In Compliance with the Requirements Defined by JEDEC Standard

No. 7A

• Chip Complexity: 145 FETs or 36 Equivalent Gates

LOGIC DIAGRAM

PIN 16 = VCC

PIN 8 = GND

RX AND CX ARE EXTERNAL COMPONENTS

PIN 1 AND PIN 15 MUST BE HARD WIRED TO GND

CX1

RX1

VCC

Q1

RESET 1

B1

A1

TRIGGER

INPUTS

Q1

1

2

4

5

3

6

7

CX2

RX2

VCC

Q2

RESET 2

B2

A2

TRIGGER

INPUTS

Q2

15

14

12

11

13

10

9

MC54/74HC4538A

PIN ASSIGNMENT

13

14

15

16

9

10

11

12

5

4

3

2

1

8

7

6

A2

RESET 2

CX2/RX2

GND

VCC

Q2

Q2

B2

A1

RESET 1

CX1/RX1

GND

GND

Q1

Q1

B1

FUNCTION TABLE

Inputs

Outputs

Reset

A

B

Q

Q

H

H

H

L

H

X

L

Not Triggered

H

H

X

Not Triggered

H

L,H,

H

Not Triggered

H

L

L,H,

Not Triggered

L

X

X

L

H

X

X

Not Triggered

D SUFFIX

SOIC PACKAGE

CASE 751B–05

N SUFFIX

PLASTIC PACKAGE

CASE 648–08

ORDERING INFORMATION

MC54HCXXXXAJ

MC74HCXXXXAN

MC74HCXXXXAD

Ceramic

Plastic

SOIC

1

16

1

16

J SUFFIX

CERAMIC PACKAGE

CASE 620–10

1

16