Dual precision monostable multivibrator

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 Cext and Rext. 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 μs to infinity. The external timing components Cext and Rext determine the duration and accuracy of the output pulse. The output pulse width (tW) is equal to Rext x Cext. 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 VDD power supply range of 3 V to 15 V referenced to VSS (usually ground). Unused inputs must be connected to VDD, VSS, 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.

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-833, method 3015 exceeds 2000 V
    • HBM JESD22-A114F exceeds 2000 V
    • MM JESD22-A115-A exceeds 200 V (C = 200 pF, R = 0 Ω)
  • Complies with JEDEC standard JESD 13-B



Type numberProduct statusVCC (V)Logic switching levelsOutput drive capability (mA)tpd (ns)Power dissipation considerationsTamb (°C)Rth(j-a) (K/W)Ψth(j-top) (K/W)Rth(j-c) (K/W)Package name
HEF4538BT-Q100Production4.5 - 15.5CMOS± 2.460medium-40~85783.537SO16


Type numberPackagePackage informationReflow-/Wave solderingPackingStatusMarkingOrderable part number, (Ordering code (12NC))
Reel 13" Q1/T1ActiveHEF4538BTHEF4538BT-Q100J
( 9353 001 14118 )

Quality, reliability & chemical content

Type numberOrderable part numberChemical contentRoHS / RHFLeadfree conversion dateMSLMSL leadfree
HEF4538BT-Q100HEF4538BT-Q100JHEF4538BT-Q100Always Pb-free11
Quality and reliability disclaimer

Documentation (5)

File nameTitleTypeDate
HEF4538B_Q100Dual precision monostable multivibratorData sheet2018-10-19
AN11051Pin FMEA HEF4000 familyApplication note2019-01-09
SOT109-1plastic, small outline package; 16 leads; 1.27 mm pitch; 9.9 mm x 3.9 mm x 1.75 mm bodyPackage information2021-01-06
SO-SOJ-WAVEFootprint for wave solderingWave soldering2009-10-08
SO-SOJ-REFLOWFootprint for reflow solderingReflow soldering2009-10-08


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