SN54AHCT123A, SN74AHCT123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
SCLS420G JUNE 1998 REVISED APRIL 2003
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
D
Inputs Are TTL-Voltage Compatible
D
Schmitt-Trigger Circuitry On A, B, and CLR
Inputs for Slow Input Transition Rates
D
Edge Triggered From Active-High or
Active-Low Gated Logic Inputs
D
Retriggerable for Very Long Output Pulses
D
Overriding Clear Terminates Output Pulse
D
Latch-Up Performance Exceeds 100 mA Per
JESD 78, Class II
D
ESD Protection Exceeds JESD 22
2000-V Human-Body Model (A114-A)
200-V Machine Model (A115-A)
1000-V Charged-Device Model (C101)
description/ordering information
These edge-triggered multivibrators feature
output pulse-duration control by three methods. In
the first method, the A input is low, and the B input
goes high. In the second method, the B input is
high, and the A input goes low. In the third method,
the A input is low, the B input is high, and the clear
(CLR) input goes high.
The output pulse duration is programmed by
selecting external resistance and capacitance
values. The external timing capacitor must be
connected between C
ext
and R
ext
/C
ext
(positive)
and an external resistor connected between
R
ext
/C
ext
and V
CC
. To obtain variable pulse
durations, connect an external variable resistance
between R
ext
/C
ext
and V
CC
. The output pulse
duration also can be reduced by taking CLR low.
ORDERING INFORMATION
TA
PACKAGE
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
PDIP N
Tube
SN74AHCT123AN
SN74AHCT123AN
SOIC
D
Tube
SN74AHCT123AD
AHCT123A
40
C to 85
C
SOIC D
Tape and reel
SN74AHCT123ADR
AHCT123A
40
C to 85
C
SSOP DB
Tape and reel
SN74AHCT123ADBR
HB123A
TSSOP PW
Tape and reel
SN74AHCT123APWR
HB123A
TVSOP DGV
Tape and reel
SN74AHCT123ADGVR
HB123A
CDIP J
Tube
SNJ54AHCT123AJ
SNJ54AHCT123AJ
55
C to 125
C
CFP W
Tube
SNJ54AHCT123AW
SNJ54AHCT123AW
LCCC FK
Tube
SNJ54AHCT123AFK
SNJ54AHCT123AFK
Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are
available at www.ti.com/sc/package.
Copyright
2003, Texas Instruments Incorporated
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SN54AHCT123A . . . J OR W PACKAGE
SN74AHCT123A . . . D, DB, DGV, N, OR PW PACKAGE
(TOP VIEW)
SN54AHCT123A . . . FK PACKAGE
(TOP VIEW)
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
1A
1B
1CLR
1Q
2Q
2C
ext
2R
ext
/C
ext
GND
V
CC
1R
ext
/C
ext
1C
ext
1Q
2Q
2CLR
2B
2A
3
2
1 20 19
9 10 11 12 13
4
5
6
7
8
18
17
16
15
14
1C
ext
1Q
NC
2Q
2CLR
1CLR
1Q
NC
2Q
2C
ext
1B
1A
NC
2A
2B
V
1R
2R
GND
NC
CC
NC No internal connection
ext
/C
ext
ext
/C
ext
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
On products compliant to MIL-PRF-38535, all parameters are tested
unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.
SN54AHCT123A, SN74AHCT123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
SCLS420G JUNE 1998 REVISED APRIL 2003
2
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
description/ordering information(continued)
Pulse triggering occurs at a particular voltage level and is not directly related to the transition time of the input
pulse. The A, B, and CLR inputs have Schmitt triggers with sufficient hysteresis to handle slow input transition
rates with jitter-free triggering at the outputs.
Once triggered, the basic pulse duration can be extended by retriggering the gated low-level-active (A) or
high-level-active (B) input. Pulse duration can be reduced by taking CLR low. CLR input can be used to override
A or B inputs. The input/output timing diagram illustrates pulse control by retriggering the inputs and early
clearing.
The variance in output pulse duration from device to device typically is less than
0.5% for given external timing
components. An example of this distribution for the 'AHCT123A is shown in Figure 10. Variations in output pulse
duration versus supply voltage and temperature are shown in Figure 6.
During power up, Q outputs are in the low state, and Q outputs are in the high state. The outputs are glitch free,
without applying a reset pulse.
For additional application information on multivibrators, see the application report, Designing With the
SN74AHC123A and SN74AHCT123A, literature number SCLA014.
FUNCTION TABLE
(each multivibrator)
INPUTS
OUTPUTS
CLR
A
B
Q
Q
L
X
X
L
H
X
H
X
L
H
X
X
L
L
H
H
L
H
#
H
L
H
These outputs are based on the
assumption that the indicated
steady-state conditions at the A and
B inputs have been set up long enough to
complete any pulse started before the
setup.
logic diagram, each multivibrator (positive logic)
CLR
Cext
Rext/Cext
R
B
A
Q
Q
SN54AHCT123A, SN74AHCT123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
SCLS420G JUNE 1998 REVISED APRIL 2003
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
input/output timing diagram
A
B
CLR
Q
Q
tw
tw
tw + trr
trr
Rext/Cext
absolute maximum ratings over operating free-air temperature (unless otherwise noted)
Supply voltage range, V
CC
(see Note 1)
0.5 V to 7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range, V
I
(see Note 2)
0.5 V to 7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output voltage range, V
O
(see Note 1)
0.5 V to V
CC
+ 0.5 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input clamp current, I
IK
(V
I
< 0)
20 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output clamp current, I
OK
(V
O
< 0 or V
O
> V
CC
)
20 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous output current, I
O
(V
O
= 0 to V
CC
)
25 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous current through V
CC
or GND
50 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Package thermal impedance,
JA
(see Note 3): D package
73
C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DB package
82
C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DGV package
120
C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
N package
67
C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PW package
108
C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range, T
stg
65
C to 150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTES:
1. Voltage values are with respect to the network ground terminal.
2. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
3. The package thermal impedance is calculated in accordance with JESD 51-7.
SN54AHCT123A, SN74AHCT123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
SCLS420G JUNE 1998 REVISED APRIL 2003
4
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
recommended operating conditions (see Note 4)
SN54AHCT123A
SN74AHCT123A
UNIT
MIN
MAX
MIN
MAX
UNIT
VCC
Supply voltage
4.5
5.5
4.5
5.5
V
VIH
High-level input voltage
2
2
V
VIL
Low-level input voltage
0.8
0.8
V
VI
Input voltage
0
5.5
0
5.5
V
VO
Output voltage
0
VCC
0
VCC
V
IOH
High-level output current
8
8
mA
IOL
Low-level output current
8
8
mA
Rext
External timing resistance
1k
1k
t/
VCC
Power-up ramp rate
1
1
ms/V
TA
Operating free-air temperature
55
125
40
85
C
NOTE 4: Unused Rext/Cext terminals should be left unconnected. All remaining unused inputs of the device must be held at VCC or GND to ensure
proper device operation. Refer to the TI application report, Implications of Slow or Floating CMOS Inputs, literature number SCBA004.
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
VCC
TA = 25
C
SN54AHCT123A
SN74AHCT123A
UNIT
PARAMETER
TEST CONDITIONS
VCC
MIN
TYP
MAX
MIN
MAX
MIN
MAX
UNIT
VOH
IOH = 50
m
A
4 5 V
4.4
4.5
4.4
4.4
V
VOH
IOH = 8 mA
4.5 V
3.94
3.8
3.8
V
VOL
IOL = 50
m
A
4 5 V
0.1
0.1
0.1
V
VOL
IOL = 8 mA
4.5 V
0.36
0.5
0.44
V
Rext/Cext
VI = VCC or GND
5.5 V
0.25
2.5
2.5
II
A, B,
and CLR
VI = VCC or GND
0 V to 5.5 V
0.1
1*
1
m
A
ICC
Quiescent
VI = VCC or GND, IO = 0
5.5 V
4
40
40
m
A
ICC
Active state
(per circuit)
VI = VCC or GND,
Rext/Cext = 0.5 VCC
5.5 V
560
750
975
975
m
A
ICC
One input at 3.4 V, Other
inputs at VCC or GND
5.5 V
1.35
1.5
1.5
mA
Ci
VI = VCC or GND
5 V
1.9
10
10
pF
* On products compliant to MIL-PRF-38535, this parameter is not production tested at VCC = 0 V.
This test is performed with the terminal in the off-state condition.
This is the increase in supply current for each input at one of the specified TTL voltage levels rather than 0 V or VCC.
timing requirements over recommended operating free-air temperature range, V
CC
= 5 V
0.5 V
(unless otherwise noted) (see Figure 1)
TEST CONDITIONS
TA = 25
C
SN54AHCT123A
SN74AHCT123A
UNIT
TEST CONDITIONS
MIN
TYP
MAX
MIN
MAX
MIN
MAX
UNIT
t
Pulse
CLR
5
5
5
ns
tw
duration
A or B trigger
5
5
5
ns
t
Pulse retrigger time
Rext = 1 k
, Cext = 100 pF
60
ns
trr
Pulse retrigger time
Rext = 1 k
, Cext = 0.01
m
F
1.5
m
s
See retriggering data in the application information section.
SN54AHCT123A, SN74AHCT123A
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATORS
SCLS420G JUNE 1998 REVISED APRIL 2003
5
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
switching characteristics over recommended operating free-air temperature range,
V
CC
= 5 V
0.5 V (unless otherwise noted) (see Figure 1)
PARAMETER
FROM
TO
TEST
TA = 25
C
SN54AHCT123A
SN74AHCT123A
UNIT
PARAMETER
FROM
TO
TEST
A
UNIT
PARAMETER
(INPUT)
(OUTPUT)
CONDITIONS
MIN
TYP
MAX
MIN
MAX
MIN
MAX
UNIT
tPLH
A
B
Q
Q
CL = 15 pF
5.3*
10*
1*
13*
1
11
ns
tPHL
A or B
Q or Q
CL = 15 pF
5.3*
10*
1*
13*
1
11
ns
tPLH
CLR
Q
Q
CL = 15 pF
7.7*
12*
1*
15*
1
13
ns
tPHL
CLR
Q or Q
CL = 15 pF
7.7*
12*
1*
15*
1
13
ns
tPLH
CLR t i
Q
Q
CL = 15 pF
8*
13*
1*
16*
1
14
ns
tPHL
CLR trigger
Q or Q
CL = 15 pF
8*
13*
1*
16*
1
14
ns
tPLH
A
B
Q
Q
CL = 50 pF
6.8
11
1
14
1
12
ns
tPHL
A or B
Q or Q
CL = 50 pF
6.8
11
1
14
1
12
ns
tPLH
CLR
Q or Q
CL = 50 pF
9.2
13
1
16
1
14
ns
tPHL
CLR
Q or Q
CL = 50 pF
9.2
13
1
16
1
14
ns
tPLH
CLR t i
Q
Q
CL = 50 pF
9.5
14
1
17
1
15
ns
tPHL
CLR trigger
Q or Q
CL = 50 pF
9.5
14
1
17
1
15
ns
CL = 50 pF,
Cext = 28 pF,
Rext = 2 k
133
200
240
240
ns
tw
Q or Q
CL = 50 pF,
Cext = 0.01
F,
Rext = 10 k
90
100
110
90
110
90
110
m
s
CL = 50 pF,
Cext = 0.1
F,
Rext = 10 k
0.9
1
1.1
0.9
1.1
0.9
1.1
ms
tw
1
%
* On products compliant to MIL-PRF-38535, this parameter is not production tested.
tw = Pulse duration at Q and Q outputs
tw = Output pulse-duration variation (Q and Q) between circuits in same package
operating characteristics, V
CC
= 5 V, T
A
= 25
C
PARAMETER
TEST CONDITIONS
TYP
UNIT
Cpd
Power dissipation capacitance
No load
29
pF
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