HEF4538BT,652

Multivibrators Overview

The HEF4538BT,652 is a dual precision monostable multivibrator from the HEF4000B logic series by Nexperia. It operates within a supply voltage range of 3 V to 15 V and supports an ambient temperature range of -40 °C to +125 °C. The device features two independent multivibrators with active LOW trigger/retrigger inputs (nA), active HIGH trigger/retrigger inputs (nB), and overriding active LOW direct reset inputs (nCD). Each channel provides outputs (nQ) and their complements (nQ). The output pulse width is determined by external timing components REXT and CEXT, typically ranging from 10 μs to infinity.

Multivibrators Feature Summary

• Dual retriggerable and resettable monostable multivibrator configuration
• High tolerance for slow trigger rise and fall times via Schmitt trigger action
• LOCMOS linear design techniques ensure precise control of output pulse width
• Fully static operation with standardized symmetrical output characteristics

Multivibrators Applications

• Pulse generation circuits requiring accurate timing
• Debouncing switches or contacts
• Timing delay applications in digital systems

Multivibrators Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to confirm package type and temperature rating. Confirm that the component meets all required environmental specifications for the intended application environment before finalizing procurement decisions.

Multivibrators Selection Notes

Select this component when a dual-channel monostable solution is required with high noise immunity and compatibility with standard CMOS logic levels. Ensure external timing components are chosen to meet the desired pulse width requirements while considering leakage currents at maximum operating temperatures.

Multivibrators Part Context

This part belongs to the HEF4000B family of CMOS logic devices manufactured by Nexperia. It utilizes LOCMOS technology to provide low power dissipation and high noise immunity. The device is housed in a SO16 plastic small outline package (SOT109-1) suitable for surface mount assembly.

Multivibrators Replacement Considerations

HEF4538BP

Multivibrators FAQ

How is the output pulse width determined?

The output pulse width is determined by the values of the external timing resistor (REXT) and capacitor (CEXT) connected to the respective pins.

What happens if the direct reset input is activated?

A LOW level at the direct reset input (nCD) terminates the output pulse immediately, regardless of the current state of the trigger inputs.