Philips hef4538b DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

For a complete data sheet, please also download:

•The IC04 LOCMOS HE4000B Logic
Family Specifications HEF, HEC

•The IC04 LOCMOS HE4000B Logic
Package Outlines/Information HEF, HEC

HEF4538B
MSI

Dual precision monostable
multivibrator

Product specification
File under Integrated Circuits, IC04

January 1995

Philips Semiconductors Product specification

Dual precision monostable multivibrator

DESCRIPTION

The HEF4538B is a dual retriggerable-resettable
monostable multivibrator. Each multivibrator has an active
LOW trigger/retrigger input (I0), an active HIGH
trigger/retrigger input (I1), an overriding active LOW direct
reset input (CD), an output (O) and its complement (O),
and two pins (CTC,
timing components Ctand Rt. Typical pulse width variation
over temperature range is ± 0,2%.

The HEF4538B may be triggered by either the positive or
the negative edges of the input pulse and will produce an

(1)

RCTC) for connecting the external

HEF4538B

MSI

accurate output pulse with a pulse width range of 10 µs to
infinity. The duration and accuracy of the output pulse are
determined by the external timing components C
The output pulse width (T) is equal to Rt× Ct. The linear
design techniques in LOCMOS guarantee precise control
of the output pulse width.

A LOW level at CDterminates the output pulse
immediately. Schmitt-trigger action in the trigger inputs
makes the circuit highly tolerant to slower rise and fall
times.

and Rt.

t

Fig.2 Pinning diagram.

HEF4538BP(N): 16-lead DIL; plastic (SOT38-1)
HEF4538BD(F): 16-lead DIL; ceramic (cerdip) (SOT74)
HEF4538BT(D): 16-lead SO; plastic (SOT109-1)
( ): Package Designator North America

PINNING

I

0A,I0B

, I

I

1A

1B

CDA, C

, O

O

A

OA, O
C

TC A

RC

TC A

B
B

, C

DB

TC B

, RC

input (HIGH to LOW triggered)
input (LOW to HIGH triggered)
direct reset input (active LOW)
output
complementary output (active LOW)
external capacitor connections
external capacitor/ resistor

TC B

(1)

connections

Note

1. Always connected to ground.

Fig.1 Functional diagram.

January 1995 2

FAMILY DATA, I

LIMITS category MSI

DD

See Family specifications.

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January 1995 3

Philips Semiconductors Product specification

Dual precision monostable multivibrator

Fig.3 Logic diagram.

HEF4538B

MSI