Philips HEF4538BU, HEF4538BT, HEF4538BPB, HEF4538BP, HEF4538BDB Datasheet

INTEGRATED CIRCUITS

DATA SHEET

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			January 1995
File under Integrated Circuits, IC04

Philips Semiconductors	Product specification

Dual precision monostable multivibrator

HEF4538B

MSI

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,(1) RCTC) for connecting the external timing components Ct and 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

Fig.1 Functional diagram.

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 Ct and Rt. 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 CD terminates the output pulse immediately. Schmitt-trigger action in the trigger inputs makes the circuit highly tolerant to slower rise and fall times.

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

I0A, I0B

I1A, I1B

CDA, CDB

OA, OB

OA, OB

CTC A, CTC B

RCTC A, RCTC B

Note

input (HIGH to LOW triggered)

input (LOW to HIGH triggered)

direct reset input (active LOW)

output

complementary output (active LOW)

external capacitor connections(1)

external capacitor/ resistor connections

1. Always connected to ground.

FAMILY DATA, IDD LIMITS category MSI

See Family specifications.

January 1995

2

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1995 January

3

Fig.3 Logic diagram.

multivibrator monostable precision Dual

HEF4538B MSI

Semiconductors Philips

specification Product