HEF4538B Dual precision monostable multivibrator Rev. 11 19 October 2018 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 and R . Typical pulse width variation over the specified temperature range is EXT EXT 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 s to infinity. The duration and accuracy of the output pulse are determined by the external timing components C and EXT R . The output pulse width (t ) is equal to R C . The linear design techniques in EXT W EXT EXT 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 power supply range of 3 V to 15 V referenced to V (usually DD SS ground). Unused inputs must be connected to V , V , or another input. DD SS 2. Features and benefits Tolerant of slow trigger rise and fall times Fully static operation 5 V, 10 V, and 15 V parametric ratings Standardized symmetrical output characteristics Specified from -40 C to +85 C and -40 C to +125 C Complies with JEDEC standard JESD 13-B 3. Ordering information Table 1. Ordering information Type number Package Temperature range Name Description Version HEF4538BT -40 C to +125 C SO16 plastic small outline package 16 leads body SOT109-1 width 3.9 mmNexperia HEF4538B Dual precision monostable multivibrator 4. Functional diagram 2 1REXT/CEXT 1 1CEXT 1Q 6 5 1A 4 1B 1Q 7 3 1CD 14 2REXT/CEXT 15 2CEXT 2Q 10 11 2A 12 2B 2Q 9 13 2CD 001aae727 Fig. 1. Functional diagram nB nA V DD nREXT/CEXT V ref1 enable nCEXT nQ V SS nCD nQ V ref2 enable 001aae734 Fig. 2. Logic diagram (one multivibrator) HEF4538B All information provided in this document is subject to legal disclaimers. Nexperia B.V. 2018. All rights reserved Product data sheet Rev. 11 19 October 2018 2 / 14