TC74HC221AP(F) Toshiba, TC74HC221AP(F) Datasheet - Page 4

• Manufacturer Part Number: TC74HC221AP(F)
• Manufacturer: Toshiba

Specifications of TC74HC221AP(F)

• Logic Family: HC
• High Level Output Current: -5.2mA
• Low Level Output Current: 5.2mA
• Quiescent Current: 4uA
• Number Of Elements: 2
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (max): 6V
• Operating Supply Voltage (typ): 2.5/3.3/5V
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Technology: CMOS
• Abs. Propagation Delay Time: 295ns
• Operating Supply Voltage (min): 2V
• Lead Free Status / RoHS Status: Compliant

Timing Chart
Functional Description
(1)
(2)
(3)
Stand-by state
triggering, the Q
comparators that relate to the timing of the output pulse, and two reference voltage supplies turn off.
The total supply current is only leakage current.
Trigger operation
input is low, and the B input has a rising signal; second, where the B input is high, and the A input
has a falling signal; and third, where the A input is low and the B input is high, and the CLR
input has a rising signal.
external capacitor discharges through Q
voltage level falls to the internal reference voltage Vref L, the output of C1 becomes low. The flip-flop
is then reset and Q
constant of external capacitor Cx and resistor Rx.
gates. It stays high even if the voltage of Rx/Cx changes from falling to rising. When Rx/Cx reaches
the internal reference voltage Vref H, the output of C2 becomes low, the output Q goes low and C2
stops its operation. That means, after triggering, when the voltage level of the Rx/Cx node reaches
Vref H, the IC returns to its MONOSTABLE state.
delays of the IC, the width of the output pulse, tw (OUT), is as follows:
Reset operation
output is held low and trigger control F/F is reset. Also, Q
The external capacitor (Cx) is fully charged to V
Trigger operation is effective in any of the following three cases. First the condition where the A
After a trigger becomes effective, comparators C1 and C2 start operating, and Q
After Q
Upon the triggering, output Q becomes high, following some delay time of the internal F/F and
With large values of Cx and Rx, and ignoring the discharge time of the capacitor and internal
In normal operation, CLR input is held high. If CLR is low, a trigger has no effect because the Q
This means if CLR input is set low, the IC goes into a wait state.
tw (OUT) = 1.0 Cx Rx
N
turns off, the voltage at the Rx/Cx node starts rising at a rate determined by the time
P
and Q
N
turns off. At that moment C1 stops but C2 continues operating.
N
transistors which are connected to the Rx/Cx node are in the off state. Two
N
. The voltage level at the Rx/Cx node drops. If the Rx/Cx
4
CC
in the stand-by state. That means, before
P
turns on and Cx is charge rapidly to V
TC74HC221AP/AF/AFN
N
is turned on. The
2007-10-01
CC
.