CD74HC123 Datasheet, PDF (7/8 Pages) Texas Instruments – High Speed CMOS Logic Dual Retriggerable Monostable Multivibrators with Resets

CD74HC123, CD74HCT123, CD74HC423, CD74HCT423
Test Circuits and Waveforms
A
B = LOW
A = HIGH
B
R
V_S
t_W
t_W
V_S
Q
t_W
t_W
FIGURE 1. OUTPUT PULSE CONTROL USING RESET INPUT
(R) PULSE FOR 123
A
B
R
V_S
t_W
B = LOW
A = HIGH
Q
t_W
V_S
t_W
FIGURE 2. OUTPUT PULSE CONTROL USING RESET INPUT
(R) FOR 423
A
B
t_W
B
A
Q
V_S
t_W
t_rT
t_W
(R = HIGH)
t_W
NOTE: Output pulse control using retrigger pulse for 123 and 423.
FIGURE 3. TRIGGERING OF ONE SHOT BY INPUT A OR INPUT B FOR A PERIOD t_W
8
6
4
2
10³ ₈
6
4
2
10² ₈
6
4
2
10¹ ₈
6
4
2
= ^100kΩ
R^X
= ^10kΩ
R^X
DC SUPPLY VOLTAGE (V_CC) = 5V
AMBIENT TEMPERATURE (T_A) = 25^oC
2 4 68 2 4 68 2 4 68 2 4 68
10³
10⁴
10⁵
10⁶
10⁷
EXTERNAL CAPACITANCE (C_X) - pF
FIGURE 4. TYPICAL OUTPUT PULSE WIDTH AS A FUNCTION
OF C_X FOR R_X = 10kΩ AND 100kΩ
0.9
EXTERNAL CAPACITANCE (C_X) = 10nF
0.8
EXTERNAL RESISTANCE (R_X) = 10kΩ TO 100kΩ
0.7
AMBIENT TEMPERATURE (T_A) = 25^oC
0.6
0.5
HCT
0.4
0.3
0.2
0.1
1 2 3 4 5 6 7 8 9 10 11
DC SUPPLY VOLTAGE (V_CC) - VOLTS
FIGURE 5. TYPICAL “K” FACTOR AS A FUNCTION OF V_CC
7