1 General description

The HEF4047B is a retriggerable astable multivibrator that can be configured as either

a positive-edge or negative-edge triggered monostable multivibrator. The output pulse

width is programmed by selection of external components (Rt and Ct). Inputs include

clamp diodes. This enables the use of current limiting resistors to interface inputs to

voltages in excess of VCC.

2 Features and benefits

2.1 General

• Monostable (one-shot) or astable (free-running) operation

• True and complemented buffered outputs

• Only one external resistor and capacitor required

2.2 Monostable multivibrator

• Positive- or negative-edge triggering

• Output pulse width independent of trigger pulse duration

• Retriggerable option for pulse-width expansion

• Long pulse width possible using small RC components with external counter provision

• Fast recovery time independent of pulse width

• Pulse-width accuracy maintained at duty cycles approaching 100

2.3 Astable multivibrator

• Free-running or gatable operating modes

• 50 duty cycle

• Oscillator output available