HEF4538B Datasheet, PDF (1/17 Pages) NXP Semiconductors – Dual precision monostable multivibrator

HEF4538B
Dual precision monostable multivibrator
Rev. 06 — 2 November 2009
Product data sheet
1. General description
The HEF4538B is a dual retriggerable-resettable monostable multivibrator. Each
multivibrator has an active LOW trigger/retrigger input (nA), an active HIGH
trigger/retrigger input (nB), an overriding active LOW direct reset input (nCD), an output
(nQ) and its complement (nQ), and two pins (nREXT/CEXT, and nCEXT, always
connected to ground) for connecting the external timing components C_EXT and R_EXT.
Typical pulse width variation over the specified temperature range is ±0.2 %.
The multivibrator may be triggered by either the positive or the negative edges of the input
pulse and will produce an 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_EXT and R_EXT. 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 trigger inputs’ Schmitt trigger action 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. It is
also suitable for use over the industrial (−40 °C to +85 °C) and automotive (−40 °C to
+125 °C) temperature ranges.
2. Features
I Tolerant of slow trigger rise and fall times
I Fully static operation
I 5 V, 10 V, and 15 V parametric ratings
I Standardized symmetrical output characteristics
I Operates across the automotive temperature range −40 °C to +125 °C
I Complies with JEDEC standard JESD 13-B
3. Applications
I Automotive and industrial