1. General description
The HEF4538B-Q100 is a dual retriggerable-resettable monostable multivibrator. Each
multivibrator has an active LOW trigger/retrigger input (nA
) and an active HIGH
trigger/retrigger input (nB). It has an overriding active LOW direct reset input (nCD
) and an
output (nQ) together with its complement (nQ
). There are also two pins for connecting the
external timing components C
ext
and R
ext
. These pins, nREXT/CEXT, and nCEXT, are
always connected to ground. Typical pulse width variation over the specified temperature
range is 0.2 %.
Either the positive or the negative edges of the input pulse can trigger the multivibrator.
The trigger produces an accurate output pulse with a pulse width range of 10 s to infinity.
The external timing components C
ext
and R
ext
determine the duration and accuracy of the
output pulse. The output pulse width (t
W
) is equal to R
ext
C
ext
. The linear design
techniques in LOCMOS (Local Oxide CMOS) guarantee precise control of the output
pulse width. A LOW level at nCD
terminates the output pulse immediately. The Schmitt
trigger action of the trigger inputs, makes the circuit highly tolerant of slower rise and fall
times.
It operates over a recommended V
DD
power supply range of 3 V to 15 V referenced to V
SS
(usually ground). Unused inputs must be connected to V
DD
, V
SS
, or another input.
This product has been qualified to the Automotive Electronics Council (AEC) standard
Q100 (Grade 1) and is suitable for use in automotive applications.
2. Features and benefits
Automotive product qualification in accordance with AEC-Q100 (Grade 1)
Specified from 40 C to +85 C and from 40 C to +125 C
Tolerant of slow trigger rise and fall times
Fully static operation
5 V, 10 V, and 15 V parametric ratings
Standardized symmetrical output characteristics
ESD protection:
MIL-STD-883, method 3015 exceeds 2000 V
HBM JESD22-A114F exceeds 2000 V
MM JESD22-A115-A exceeds 200 V (C = 200 pF, R = 0 )
Complies with JEDEC standard JESD 13-B
HEF4538B-Q100
Dual precision monostable multivibrator
Rev. 2 — 10 December 2013 Product data sheet
