TC74HC221AP/AF TOSHIBA CMOS Digital Integrated Circuit Silicon Monolithic TC74HC221AP, TC74HC221AF Dual Monostable Multivibrator The TC74HC221A is a high speed CMOS MONOSTABLE 2 TC74HC221AP MULTIVIBRATOR fabricated with silicon gate C MOS technology. It achieves the high speed operation similar to equivalent LSTTL while maintaining the CMOS low power dissipation. There are two trigger inputs, A input (negative edge), and B input (positive edge). These inputs are valid for a slow rise/fall time signal (tr = tf = 1 s) as they are schmitt trigger inputs. This device may also be triggered by using CLR input (positive edge). After triggering, the output stays in a MONOSTABLE state for TC74HC221AF a time period determined by the external resistor and capacitor (Rx, Cx ). A low level at the CLR input breaks this state. Limits for Cx and Rx are: External capacitor, Cx: No limit External resistor, Rx: V = 2.0 V more than 5 k CC V 3.0 V more than 1 k CC All inputs are equipped with protection circuits against static discharge or transient excess voltage. Features (Note) Weight High speed: t = 25 ns (typ.) at V = 5 V pd CC DIP16-P-300-2.54A : 1.00 g (typ.) SOP16-P-300-1.27A : 0.18 g (typ.) Low power dissipation Standy by State: I = 4 A (max) at Ta = 25C CC Active State: I = 700 A (max) at Ta = 25C CC High noise immunity: V = V = 28% V (min) NIH NIL CC Output drive capability: 10 LSTTL loads Symmetrical output impedance: I = I = 4 mA (min) OH OL Balanced propagation delays: t t pLH pHL Wide operating voltage range: V (opr) = 2 to 6 V CC Pin and function compatible with 74LS221 Note: In the case of using only one circuit, CLR should be tied to GND, Rx/CxCxQ Q should be tied to OPEN, the other inputs should be tied to VCC or GND. Start of commercial production 1988-05 1 2016-12-02 TC74HC221AP/AF Pin Assignment IEC Logic Symbol Block Diagram (Note) Note: Cx, Rx, Dx are external capacitor, resistor, and diode, respectively. Note: External clamping diode, Dx The external capacitor is charged to VCC level in the wait state, i.e. when no trigger is applied. If the supply voltage is turned off, Cx is discharges mainly through the internal (parasitic) diode. If Cx is sufficiently large and VCC drops rapidly, there will be some possibility of damaging the IC through in rush current or latch-up. If the capacitance of the supply voltage filter is large enough and VCC drops slowly, the in rush current is automatically limited and damage to the IC is avoided. The maximum value of forward current through the parasitic diode is 20 mA. In the case of a large Cx, the limit of fall time of the supply voltage is determined as follows: > tf (VCC - 0.7) Cx/20 mA = (tf is the time between the supply voltage turn off and the supply voltage reaching 0.4 VCC.) In the even a system does not satisfy the above condition, an external clamping diode (Dx) is needed to protect the IC from rush current. 2 2016-12-02