HEF4538BP,652

Logic - Multivibrators

The HEF4538BP​, 652 is a monostable multivibrator with reset and complementary outputs. It has two programmable regeneration modes, self-timed mode and pulse duration mode. This integrated circuit utilises CMOS logic providing an extremely low-power logic resource, with precision timer capabilities with minimum power drain on battery power sources.

Application Field

The HEF4538BP​, 652 is typically used in automotive, commercial and consumer electronic systems requiring precision timing, counting or delay functions as input signals. The reset and complementary outputs provide a programmable reset pulse, either self-timed or of fixed duration. It is also useful for frequency division and clock formatting.

Working Principle

The HEF4538BP​, 652 combines two internally connected circuits and functions as a basic multivibrator. In monostable mode, the high and low threshold voltage levels on the external reset pin determine the logic state of the Q output. When the external reset pin is set high, the Q output will be low and the complementary output, Q* will be high. When the external reset pin is set low, the Q output will remain high and the complementary output, Q* will become low.

In pulse duration mode, the delay time is determined by the externally programmable R and C components, the on-chip current limiting resistors, and the external clock frequency. The reset and complementary outputs then activate and deactivate the reset pin according to the delay time. When the external reset pin is triggered, the Q output will be low and the complementary output, Q* will become high. When the external reset pin is released, the Q output will stay low and the complementary output, Q* will be low.

Conclusion

In conclusion, the HEF4538BP​, 652 is a highly-integrated monostable multivibrator with reset and complementary outputs, capable of two programmable refresh modes and offering extremely low power consumption. This integrated circuit is typically used in automotive, consumer and commercial applications as a precision timer, counter or delay function as inputs. It is also suitable for frequency division and clock formatting.