The M74HC221 is an high speed CMOS MONOSTABLE MULTIVIBRATOR fabricated with silicon gate C2MOS technology.
There are two trigger inputs, A INPUT (negative edge) and B INPUT (positive edge).
Triggering on the B input occurs at a particular voltage threshold and is not related to rise and fall time of the applied pulse. The device may also be trigger by using the CLR input (positive edge) because of the Schimtt-trigger input; aftert riggering the output maintains the MONOSTABLE STATE for the time period determined by the external resistor Rx and capacitor Cx. Taking CLR low breaks this MONOSTABLE STATE. If the next trigger pulse occurs during the MONOSTABLE period it makes the MONOSTABLE period longer.
Limit for values of Cx and Rx :
Cx : NO LIMIT
Rx : Vcc < 3.0V 5KΩ to 1MΩ
Vcc > 3.0V 1KΩ to 1MΩ
K ≅ 0.7
All inputs are equipped with protection circuits against static discharge and transient excess voltage.
■ HIGH SPEED :
tPD = 24 ns (TYP.) at VCC = 6V
■ LOW POWER DISSIPATION:
STAND BY STATE :
ICC=4µA (MAX.) at TA=25°C
ACTIVE STATE :
ICC=700µA (MAX.) at VCC = 5V
■ HIGH NOISE IMMUNITY:
VNIH = VNIL = 28 % VCC (MIN.)
■ SYMMETRICAL OUTPUT IMPEDANCE:
|IOH| = IOL = 4mA (MIN)
■ BALANCED PROPAGATION DELAYS:
tPLH ≅ tPHL
■ WIDE OPERATING VOLTAGE RANGE:
VCC (OPR) = 2V to 6V
■ WIDE OUTPUT PULSE WIDTH RANGE :
tWOUT = 150 ns ~ 60 s OVER AT VCC = 4.5 V
■ PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 221
(Picture:Pinout / Diagram)
