S E M I C O N D U C T O R
1
Features
Overriding Reset Terminates Output Pulse
Triggering From the Leading or Trailing Edge
Q and Q Buffered Outputs
Separate Resets
Wide Range of Output-Pulse Widths
Schmitt Trigger on Both A and B Inputs
Fanout (Over Temperature Range)
- Standard Outputs . . . . . . . . . . . . . . . 10 LSTTL Loads
- Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads
Wide Operating Temperature Range . . . -55
o
C to 125
o
C
Balanced Propagation Delay and Transition Times
Significant Power Reduction Compared to LSTTL
Logic ICs
HC Types
- 2V to 6V Operation
- High Noise Immunity: N
IL
= 30%, N
IH
= 30%of V
CC
at
V
CC
= 5V
HCT Types
- 4.5V to 5.5V Operation
- Direct LSTTL Input Logic Compatibility,
V
IL
= 0.8V (Max), V
IH
= 2V (Min)
- CMOS Input Compatibility, I
l
1
A at V
OL
, V
OH
Pinout
CD74HC123, CD74HCT123, CD74HC423, CD74HCT423
(PDIP, SOIC)
TOP VIEW
Description
The Harris CD74HC123, CD74HCT123, CD74HC423 and
CD74HCT423 are dual monostable multivibrators with
resets. They are all retriggerable and differ only in that the
123 types can be triggered by a negative to positive reset
pulse; whereas the 423 types do not have this feature. An
external resistor (R
X
) and an external capacitor (C
X
) control
the timing and the accuracy for the circuit. Adjustment of Rx
and C
X
provides a wide range of output pulse widths from
the Q and Q terminals. Pulse triggering on the A and B
inputs occur at a particular voltage level and is not related to
the rise and fall times of the trigger pulses.
Once triggered, the output pulse width may be extended by
retriggering inputs A and B. The output pulse can be
terminated by a LOW level on the Reset (R) pin. Trailing
edge triggering (A) and leading edge triggering (B) inputs
are provided for triggering from either edge of the input
pulse. If either Mono is not used each input on the unused
device (A, B, and R) must be terminated high or low.
The minimum value of external resistance, Rx is typically 5k
.
The minimum value external capacitance, C
X
, is 0pF. The
calculation for the pulse width is t
W
= 0.45 R
X
C
X
at V
CC
= 5V.
14
15
16
9
13
12
11
10
1
2
3
4
5
7
6
8
1A
1B
1R
1Q
2Q
2C
X
GND
2R
X
C
X
V
CC
1C
X
1Q
2Q
2R
2B
2A
1R
X
C
X
Ordering Information
PART NUMBER
TEMP. RANGE (
o
C)
PACKAGE
PKG.
NO.
CD74HC123E
-55 to 125
16 Ld PDIP
E16.3
CD74HCT123E
-55 to 125
16 Ld PDIP
E16.3
CD74HC423E
-55 to 125
16 Ld PDIP
E16.3
CD74HCT423E
-55 to 125
16 Ld PDIP
E16.3
CD74HC123M
-55 to 125
16 Ld SOIC
M16.15
CD74HCT123M
-55 to 125
16 Ld SOIC
M16.15
CD74HC423M
-55 to 125
16 Ld SOIC
M16.15
CD74HCT423M
-55 to 125
16 Ld SOIC
M16.15
NOTES:
1. When ordering, use the entire part number. Add the suffix 96 to
obtain the variant in the tape and reel.
2. Wafer or die for this part number is available which meets all elec-
trical specifications. Please contact your local sales office or
Harris customer service for ordering information.
September 1997
CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures.
Copyright
Harris Corporation 1997
File Number
1708.1
CD74HC123, CD74HCT123,
CD74HC423, CD74HCT423
High Speed CMOS Logic Dual Retriggerable
Monostable Multivibrators with Resets
2
Functional Diagram
TRUTH TABLE
INPUTS
OUTPUTS
A
B
R
Q
Q
CD74HC/HCT123
H
X
H
L
H
X
L
H
L
H
L
H
H
H
X
X
L
L
H
L
H
CD74HC/HCT423
H
X
H
L
H
X
L
H
L
H
L
H
H
H
X
X
L
L
H
NOTE: H = High Voltage Level, L = Low Voltage Level,
X = Don't Care.
2R
11
2A
9
10
5
12
2Q
2Q
2B
MONO 2
V
CC
6
7
2Cx
2RxCx
1R
3
1A
2
1
13
4
1Q
1Q
1B
MONO 1
V
CC
14
15
1Cx
1RxCx
1Cx
1Rx
2Cx
2Rx
CD74HC123, CD74HCT123, CD74HC423, CD74HCT423
3
Absolute Maximum Ratings
Thermal Information
DC Supply Voltage, V
CC
. . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 7V
DC Input Diode Current, I
IK
For V
I
< -0.5V or V
I
> V
CC
+ 0.5V
. . . . . . . . . . . . . . . . . . . . . .
20mA
DC Output Diode Current, I
OK
For V
O
< -0.5V or V
O
> V
CC
+ 0.5V
. . . . . . . . . . . . . . . . . . . .
20mA
DC Output Source or Sink Current per Output Pin, I
O
For V
O
> -0.5V or V
O
< V
CC
+ 0.5V
. . . . . . . . . . . . . . . . . . . .
25mA
DC V
CC
or Ground Current, I
CC or
I
GND
. . . . . . . . . . . . . . . . . .
50mA
Operating Conditions
Temperature Range (T
A
) . . . . . . . . . . . . . . . . . . . . . -55
o
C to 125
o
C
Supply Voltage Range, V
CC
HC Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2V to 6V
HCT Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.5V to 5.5V
DC Input or Output Voltage, V
I
, V
O
. . . . . . . . . . . . . . . . . 0V to V
CC
Input Rise and Fall Time
2V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000ns (Max)
4.5V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500ns (Max)
6V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400ns (Max)
Thermal Resistance (Typical, Note 3)
JA
(
o
C/W)
PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
90
SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
115
Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . 150
o
C
Maximum Storage Temperature Range . . . . . . . . . .-65
o
C to 150
o
C
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300
o
C
(SOIC - Lead Tips Only)
CAUTION: Stresses above those listed in "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress only rating and operation
of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
3.
JA
is measured with the component mounted on an evaluation PC board in free air.
DC Electrical Specifications
PARAMETER
SYMBOL
TEST
CONDITIONS
V
CC
(V)
25
o
C
-40
o
C TO 85
o
C -55
o
C TO 125
o
C
UNITS
V
I
(V)
I
O
(mA)
MIN
TYP
MAX
MIN
MAX
MIN
MAX
HC TYPES
High Level Input
Voltage
V
IH
-
-
2
1.5
-
-
1.5
-
1.5
-
V
4.5
3.15
-
-
3.15
-
3.15
-
V
6
4.2
-
-
4.2
-
4.2
-
V
Low Level Input
Voltage
V
IL
-
-
2
-
-
0.5
-
0.5
-
0.5
V
4.5
-
-
1.35
-
1.35
-
1.35
V
6
-
-
1.8
-
1.8
-
1.8
V
High Level Output
Voltage
CMOS Loads
V
OH
V
IH
or V
IL
-0.02
2
1.9
-
-
1.9
-
1.9
-
V
-0.02
4.5
4.4
-
-
4.4
-
4.4
-
V
-0.02
6
5.9
-
-
5.9
-
5.9
-
V
High Level Output
Voltage
TTL Loads
-
-
-
-
-
-
-
-
-
V
-4
4.5
3.98
-
-
3.84
-
3.7
-
V
-5.2
6
5.48
-
-
5.34
-
5.2
-
V
Low Level Output
Voltage
CMOS Loads
V
OL
V
IH
or V
IL
0.02
2
-
-
0.1
-
0.1
-
0.1
V
0.02
4.5
-
-
0.1
-
0.1
-
0.1
V
0.02
6
-
-
0.1
-
0.1
-
0.1
V
Low Level Output
Voltage
TTL Loads
-
-
-
-
-
-
-
-
-
V
4
4.5
-
-
0.26
-
0.33
-
0.4
V
5.2
6
-
-
0.26
-
0.33
-
0.4
V
Input Leakage
Current
I
I
V
CC
or
GND
-
6
-
-
0.1
-
1
-
1
A
Quiescent Device
Current
I
CC
V
CC
or
GND
0
6
-
-
8
-
80
-
160
A
CD74HC123, CD74HCT123, CD74HC423, CD74HCT423
4
HCT TYPES
High Level Input
Voltage
V
IH
-
-
4.5 to
5.5
2
-
-
2
-
2
-
V
Low Level Input
Voltage
V
IL
-
-
4.5 to
5.5
-
-
0.8
-
0.8
-
0.8
V
High Level Output
Voltage
CMOS Loads
V
OH
V
IH
or V
IL
-0.02
4.5
4.4
-
-
4.4
-
4.4
-
V
High Level Output
Voltage
TTL Loads
-4
4.5
3.98
-
-
3.84
-
3.7
-
V
Low Level Output
Voltage
CMOS Loads
V
OL
V
IH
or V
IL
0.02
4.5
-
-
0.1
-
0.1
-
0.1
V
Low Level Output
Voltage
TTL Loads
4
4.5
-
-
0.26
-
0.33
-
0.4
V
Input Leakage
Current
I
I
V
CC
and
GND
0
5.5
-
0.1
-
1
-
1
A
Quiescent Device
Current
I
CC
V
CC
or
GND
0
5.5
-
-
8
-
80
-
160
A
Additional Quiescent
Device Current Per
Input Pin: 1 Unit Load
I
CC
V
CC
-2.1
-
4.5 to
5.5
-
100
360
-
450
-
490
A
NOTE: For dual-supply systems theoretical worst case (V
I
= 2.4V, V
CC
= 5.5V) specification is 1.8mA.
DC Electrical Specifications
(Continued)
PARAMETER
SYMBOL
TEST
CONDITIONS
V
CC
(V)
25
o
C
-40
o
C TO 85
o
C -55
o
C TO 125
o
C
UNITS
V
I
(V)
I
O
(mA)
MIN
TYP
MAX
MIN
MAX
MIN
MAX
HCT Input Loading Table
INPUT
UNIT LOADS
All
0.35
NOTE: Unit Load is
I
CC
limit specified in DC Electrical Table, e.g.
360
A max at 25
o
C.
Prerequisite for Switching Specifications
PARAMETER
SYMBOL V
CC
(V)
25
o
C
-40
o
C TO 85
o
C
-55
o
C TO 125
o
C
UNITS
MIN
TYP
MAX
MIN
TYP
MAX
MIN
TYP
MAX
HC TYPES
Minimum Input,
Pulse Width
t
WL
A
2
100
-
-
125
-
-
150
-
-
ns
4.5
20
-
-
25
-
-
30
-
-
ns
6
17
-
-
21
-
-
26
-
-
ns
B
t
WH
2
100
-
-
125
-
-
150
-
-
ns
4.5
20
-
-
25
-
-
30
-
-
ns
6
17
-
-
21
-
-
26
-
-
ns
CD74HC123, CD74HCT123, CD74HC423, CD74HCT423
5
R
t
WL
2
100
-
-
125
-
-
150
-
150
ns
4.5
20
-
-
25
-
-
30
-
30
ns
6
17
-
-
21
-
-
26
-
26
ns
A and B Hold Time
t
H
2
50
-
-
65
-
-
75
-
75
ns
4.5
10
-
-
13
-
-
15
-
15
ns
6
9
-
-
11
-
-
13
-
13
ns
Reset Removal Time
t
REM
2
50
-
-
65
-
-
75
-
75
ns
4.5
10
-
-
13
-
-
15
-
15
ns
6
9
-
-
11
-
-
13
-
13
ns
Retrigger Time Number
t
rT
5
-
-
-
-
-
-
-
-
-
ns
R
X
= 10K
, C
X
= 0
-
50
-
-
63
-
-
76
-
ns
Output Pulse Width
t
W
5
Q or Q
R
X
= 10K
, C
X
= 10nF
40
-
50
38.7
-
51.3
38.2
-
51.8
s
HCT TYPES
Minimum Input,
Pulse Width
t
WL
5
-
A
20
-
-
25
-
-
30
-
-
ns
B
t
WH
20
-
-
25
-
-
30
-
-
ns
R
t
WL
20
-
-
25
-
-
30
-
-
ns
A and B Hold Time
t
H
5
10
-
-
13
-
-
15
-
-
ns
Reset Removal Time
t
REM
5
10
-
-
13
-
-
15
-
ns
Retrigger Time Number
(Note 4)
R
X
= 10K
, C
X
= 0
t
rT
5
-
50
-
-
63
-
-
76
-
ns
Output Pulse Width Q or Q
t
W
5
40
-
50
38.7
-
51.3
38.2
-
51.8
s
R
X
= 10K
, C
X
= 10nF
NOTE:
4. Time to trigger depends on the values of R
X
and C
X
. The output pulse width can only be extended when the time between the active-
going edges of the trigger input pulses meet the minimum retrigger time requirement.
Prerequisite for Switching Specifications
(Continued)
PARAMETER
SYMBOL V
CC
(V)
25
o
C
-40
o
C TO 85
o
C
-55
o
C TO 125
o
C
UNITS
MIN
TYP
MAX
MIN
TYP
MAX
MIN
TYP
MAX
CD74HC123, CD74HCT123, CD74HC423, CD74HCT423
6
Switching Specifications
C
L
= 50pF, Input t
r
, t
f
= 6ns, R
X
= 10K
, C
X
= 0
PARAMETER
SYMBOL
TEST
CONDITIONS
V
CC
(V)
25
o
C
-40
o
C TO
85
o
C
-55
o
C TO
125
o
C
UNITS
MIN
TYP
MAX
MIN
MAX
MIN
MAX
HC TYPES
Trigger Propagation Delay
t
PHL
C
L
= 50pF
A, B, R to Q
2
-
-
300
-
375
-
450
ns
4.5
-
-
60
-
75
-
90
ns
C
L
= 15pF
5
-
25
-
-
-
-
-
ns
C
L
= 50pF
6
-
-
51
-
64
-
76
ns
A, B, R to Q
t
PHL
C
L
= 50pF
2
-
-
320
-
400
-
480
ns
4.5
-
-
64
-
80
-
96
ns
C
L
= 15pF
5
-
26
-
-
-
-
-
ns
C
L
= 50pF
6
-
-
54
-
68
-
82
ns
Reset Propagation Delay
t
PHL
, t
PLH
C
L
= 50pF
2
-
-
215
-
270
-
325
ns
R to Q or Q
4.5
-
-
43
-
54
-
65
ns
6
-
-
37
-
46
-
55
ns
Output Transition Time
t
THL
, t
TLH
C
L
= 50pF
2
-
-
75
-
95
-
110
ns
4.5
-
-
15
-
19
-
22
ns
6
-
-
13
-
16
-
19
ns
Output Pulse Width
-
-
5
R
X
= 10K
, C
X
= 10pF
-
45
-
-
-
-
-
s
Pulse Width Match Between
Circuits In the Same Package
-
-
5
R
X
= 10K
, C
X
= 10pF
-
2
-
-
-
-
-
%
Power Dissipation Capacitance
C
PD
C
L
= 15pF
5
-
-
-
-
-
-
-
pF
Input Capacitance
C
IN
C
L
= 50pF
-
10
-
10
-
10
-
10
pF
NOTES:
5. C
PD
is used to determine the dynamic power consumption, per multivibrator.
6. P
D
= (C
PD
+ C
X
) V
CC
2
f
i
(C
L
V
CC
2
f
O
) where f
i
= input frequency, f
O
= Output Frequency, C
L
= Output Load Capacitance,
C
X
= External Capacitance V
CC
= Supply Voltage assuming f
i
I
t
W
------
CD74HC123, CD74HCT123, CD74HC423, CD74HCT423
7
Test Circuits and Waveforms
FIGURE 1. OUTPUT PULSE CONTROL USING RESET INPUT
(R) PULSE FOR 123
FIGURE 2. OUTPUT PULSE CONTROL USING RESET INPUT
(R) FOR 423
FIGURE 3. TRIGGERING OF ONE SHOT BY INPUT A OR INPUT B FOR A PERIOD t
W
FIGURE 4. TYPICAL OUTPUT PULSE WIDTH AS A FUNCTION
OF C
X
FOR R
X
= 10k
AND 100k
FIGURE 5. TYPICAL "K" FACTOR AS A FUNCTION OF V
CC
B = LOW
A = HIGH
t
W
t
W
V
S
V
S
Q
R
B
A
t
W
t
W
A
B
R
B = LOW
A = HIGH
Q
t
W
V
S
V
S
t
W
t
W
A
B
B
A
Q
t
rT
(R = HIGH)
t
W
t
W
t
W
t
W
NOTE: Output pulse control using retrigger pulse for 123 and 423.
V
S
OUTPUT PULSE WIDTH (
s)
2
4
6
8
10
3
10
2
10
1
2
4
6
8
2
4
6
8
2
4
6
8
EXTERNAL CAPACITANCE (C
X
) - pF
2
4 6 8
10
3
10
4
2
4 6 8
2
4 6 8
2
4 6 8
10
5
10
6
10
7
R
X
= 100k
R
X
= 10k
DC SUPPLY VOLTAGE (V
CC
) = 5V
AMBIENT TEMPERATURE (T
A
) = 25
o
C
EXTERNAL CAPACITANCE (C
X
) = 10nF
EXTERNAL RESISTANCE (R
X
) = 10k
TO 100k
AMBIENT TEMPERATURE (T
A
) = 25
o
C
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
1
2
3
4
5
6
7
8
9
10
11
"K" F
A
CT
OR
HCT
DC SUPPLY VOLTAGE (V
CC
) - VOLTS
CD74HC123, CD74HCT123, CD74HC423, CD74HCT423
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