ROHM BU4538B Datasheet

1

Standard ICs

Dual precision monostable
multivibrator

BU4538B

The BU4538B is a monostable multivibrator that can be reset and retriggered. It is triggered from either edge of an
input pulse. As the output pulse width and accuracy are determined by the external timing constants Cx and Rx, a
wide range of accurate output pulse widths is available. Linear CMOS technology makes it possible to control the
output pulse width with greater accuracy. Determination is made based on t

WOUT = Rx · Cx throughout the entire

power supply voltage range, eliminating the necessity for other coefficients.

•

Features

1) Low power dissipation.

2) Wide range of operating power supply voltages.

3) High input impedance.

4) High fan-out.

5) Direct drive of 2 L-TTL inputs and 1 LS-TTL input.

•

Block diagram

•

Logic circuit diagram

2

T

2A

T1A

AA

BA

QA

Q

C

D

T1
T2

Q

QA

CDA

3

4

5

6

7

8

15

14

13

12

11

10

9

V

SS

1

T

1B

VDD

CDB

AB

BB

QB

T2B

QB

16

BA

Q

C

D

T1
T2

Q

BA

VDD

RX

2 (14)

1 (15)

4 (12)

T

1

Vref1 Enable

S

R

V

ref2

Reset Latch

QQ

Enable

A
B

C

X

VDD

Control

Output

Latch

QS

QR

T2

CD

5 (11)
3 (13)

6 (10)
7 (9)

•

Truth table

INPUT OUTPUT

ABC

D Q

Q
HH
LH L H

HLH
LH
XXL L H

H

2

Standard ICs BU4538B

•

Absolute maximum ratings (Ta = 25°C, VSS = 0V)

Parameter Symbol Limits Unit

V

DD – 0.3 ~ + 18 V

mW

°C
°C

V

IN – 0.3 ~ VDD + 0.3 V

1000 (DIP)

– 55 ~ + 150

– 40 ~ + 85

Pd
Topr
Tstg

Power supply voltage
Power dissipation
Operating temperature
Storage temperature
Input voltage

Parameter Symbol Min. Typ. Max. Unit Conditions

V

IH

3.5

——

V

5

—

7.0

——

10

11.0

——

15

V

IL

——

1.5
V

5

———

3.0 10

——

4.0 15

I

IH

——

0.3 µ

A15V

IH = 15V

I

IL

——

– 0.3 µ

A15V

IL = 0V

V

OH

4.95

——

V

5

I

O = 0mA9.95

——

10

14.95

——

15

V

OL

——

0.05
V

5

I

O = 0mA

——

0.05 10

——

0.05 15

I

OH

– 0.16

——

mA

5VOH = 4.6V

– 0.4

——

10 V

OH = 9.5V

– 1.2

——

15 V

OH = 13.5V

I

OL

0.44

——

mA

5VOL = 0.4V

1.1

——

10 V

OL = 0.5V

3.0

——

15 V

OL = 1.5V

I

DD

——

20

µ

A

5

V

I = VDD or GND

——

40 10

——

80 15

V

DD (V)

Input high level voltage

Input low level voltage

Input high level current
Input low level current

Output high level voltage

Output low level voltage

Output high level current

Output low level current

Static current dissipation

•

Electrical characteristics

DC characteristics (unless otherwise noted, Ta = 25°C, V

SS = 0V)