1/12July 2001
■HIGH SPEED :
tPD = 23 ns (TYP.) at VCC = 6V
■LOW POWER DISSIPATION:
STAND BY STATE :
ICC=4µA (MAX.) at T A=25°C
ACTIVE STATE :
ICC=200µA (MAX.) at VCC = 5V
■HIGH NOISE IMMUNITY:
VNIH = VNIL = 28 % VCC (MIN.)
■SYMMETRICAL OUTPUT IMPEDANCE:
|IOH| = IOL = 4mA (MIN)
■BALANCED PROPAGATION DELAYS:
tPLH ≅ tPHL
■WIDE OPERATING VOLTAGE RANGE:
VCC (O PR) = 2V to 6V
■WIDE OUTPUT PULSE WIDTH RANGE :
tWOUT = 120 ns ~ 60 s OVER AT V CC = 4.5 V
■PIN AND FUNCTION COMPATIBLE WIT H
74 SERIES 123
DESCRIPTION
The M74HC123 is an high speed CMOS
MONOSTABLE MULTIVIBRATO R fabricated with
silicon gat e C2MOS technology.
There are two trigger inputs, A INPUT (negative
edge) and B IN PU T (positive edge). These inputs
are valid for slow rising/falling signals, (tr=tf=l sec).
The device may also be triggered by using the
CLR input (positive-edge) because of the
Schmitt-trigger input; after triggering the output
maintains the MONOSTABLE state for the time
period de termined by the external res istor Rx and
capacitor Cx. When Cx > 10nF and Rx > 10KΩ,
the output pulse width value is approsimatively
given by the formula : t W(OUT ) = K · Cx · Rx.
(K ≅ 0.45).
Taking CLR low breaks this MONOSTABLE
ST ATE . If the ne xt trigger pul se oc curs du ring the
MONOSTABLE period it makes the
MONOSTABLE period longer. Limit for values of
Cx and Rx : Cx : NO LIMIT
Rx : Vcc < 3.0 V 5KΩ to 1MΩ
Vcc > 3.0V 1KΩ to 1MΩ
All inputs are equipped with protection circuits
against static discharge and transient excess
voltage.
M74HC123
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATOR
PIN CONNECTION AND IEC LO GIC SYMBOLS
ORDER CODES
PACKAGE TUBE T & R
DIP M74HC123B1R
SOP M74HC123M1R M74HC123RM13TR
TSSOP M74HC123TTR
TSSOPDIP SOP
M74HC123
2/12
INPUT AND OUT PUT EQUIVALENT CIRCUIT PIN DESCRIPTION
TRUTH TABLE
X : Don’t Care
PIN No SYMBOL NAME AND FUNCTION
1,9 1A, 2A Trigger Inputs (Negative
Edge Triggered)
2, 10 1B, 2B Trigger Inputs (Positive
Edge Triggered)
3, 11 1 CLR
2 CLR
Direct Reset LOW and
trigger Action at Positive
Edge
4, 12 1Q, 2Q Outputs (Active Low)
72RX/CXExternal Resistor
Capacitor Connection
13, 5 1Q, 2Q Outputs (Active High)
14, 6 1CX
2CXExternal Capacitor
Connection
15 1RX/CXExternal Resistor
Capacitor Connection
8 GND Ground (0V)
16 Vcc Positive Supply Voltage
INPUTS OUTPUTS NOTE
ABCLRQQ
H H OUTPUT ENABLE
X L H L H INHIBIT
H X H L H INHIBIT
L H OUTPUT ENABLE
L H OUTPUT ENABLE
X X L L H INHIBIT
M74HC123
3/12
SYSTEM DI AGRAM
Th i s l ogic dia gram has not be used to estimat e propagation del ays
TIMING CHART
M74HC123
4/12
BLOCK DIAGRAM
(1) Cx, Rx , Dx are ext ernal co m ponents.
(2) Dx is a clamping diode.
Th e external capacit or i s c harged to V cc in the st and-b y-state, i.e. no trigge r. When the supply voltage is turned off Cx is discharged mainly
trough an int ernal paras itic diode(see figures). If Cx is su fficiently large and V cc dec reases rapi dly, there will b e s ome po ssibility of damaging
the I .C. with a surge current or latch- up. If the vo l tage sup pl y f i l ter capa ci t or is large enough and Vcc decrease slow l y, the s urg e current is
automat ically limited and damage to the I.C. is avoided. The maximum forward current of the parasitic diode is approximatel y 20 mA. In case s
where Cx is large the time taken for the supply voltage to fall to 0.4 Vcc can be calculated as follows :
tf > (Vcc - 0.7) x Cx/20mA
In cases where tf is too short an externa l clam ping diode is required to p rotect the I.C. fr om t he surge current .
FUNCTIONAL DESCRIPTION
STAND-BY STATE
The external capac itor,Cx, is f ully charged t o Vcc
in the stand-by state. Hence, before triggering,
transistor Qp and Qn (connected to the Rx/Cx
node) are both turned-off. The two comparators
that control the timing and the two reference
voltage sources stop operating. The total supply
current is therefore onl y leakage current.
TRIGGER OPERATION
Triggeri ng occurs when :
1 st) A is "LOW" and B has a falling ed ge;
2 nd) B is "HIGH" and A has a rising edge;
3 rd) A is "LOW" and B is HIGH and C1 has a
rising edge;
After the multivibrator has been retriggered
comparator C1 and C2 start operating and Qn is
turned on. Cx then discharges through Qn. The
voltag e at the node R/C ext ernal falls.
When it reaches VREFL the output of comparator
C1 becomes low. This in turn reset the flip-flop
and Qn is turned off.
At this point C1 stops functioni ng but C2 continues
to operate.
The voltage at R/C external begins to rise with a
time cons tant set by the ext ernal com pon ents Rx,
Cx.
Triggering the multivibrator causes Q to go high
after internal delay due to the flip-flop and the
gate. Q remains high until the voltage at R/C
external rises again to VREFH . At this point C2
output goes low and O goes low. C2 stop
operating. That means that after triggering when
the voltage R/C external returns to VREFH the
multivibrator has returned to its MONOSTABLE
STATE. In the case where Rx · Cx are large
enough and the discharge time of the capacitor
and t he delay tim e in the I.C. can be ignored, the
width of the output pulse tw (out) is as follows :
tW(OUT) = 0.45 Cx · Rx
RE - TRIGGERED OPERATION
When a second trigger pulse follows the first its
effect wi ll depend on the state of the multivibrator.
If the capacitor Cx is being charged the voltage
level of R/C external falls to VREFL again and Q
remains High i.e. the retrigger pulse arrives in a
time shorte r than th e period Rx · Cx se conds, the
capacitor charging time constant. If the second
trigger pulse is very clos e to the initial t rigger pulse
it is ineffective ; i. e. the second trigger mu st arrive
in the capacitor discharge cycle to be ineffective;
Hence the minimum time for a second trigger to be
effective depends on Vcc and Cx
RESET OPERATION
CL is normally high. If CL is low, the trigger is not
effective because Q output goes low and trigger
control f lip- f lo p is rese t .
Also transis tor Op is turned on and Cx is c harged
quickly to Vcc. This means if CL input goes low the
IC becomes waiting state both in operating and
non operating state.
M74HC123
5/12
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are t hose v alues beyond which damage to the device may occur. Functional operation under these conditions is
not implie d
(* ) 500mW a t 65 °C; derate to 30 0m W by 10mW/°C fr om 65 °C to 85°C
RECOMMENDE D OPERATING CONDITIONS
The Maxi mum allowable values of Cx and Rx are a function of leakage of capacitor Cx, the leakage of devic e and leakage due to the boa rd
layout and surface resist ance . Susceptibility to ex ternally induced noise ma y occur for Rx > 1MΩ
Symbol Parameter Value Unit
VCC Supply Voltage -0.5 to +7 V
VIDC Input Voltage -0.5 to VCC + 0.5 V
VODC Output Voltage -0.5 to VCC + 0.5 V
IIK DC Input Diode Current ± 20 mA
IOK DC Output Diode Current ± 20 mA
IODC Output Current ± 25 mA
ICC or IGND DC VCC or Ground Curre nt ± 50 mA
PDPower Dissipation 500(*) mW
Tstg Storage Temperature -65 to +150 °C
TLLead Temperature (10 sec) 300 °C
Symbol Parameter Value Unit
VCC Supply Voltage 2 to 6 V
VIInput Voltage 0 to VCC V
VOOutput Voltage 0 to VCC V
Top Operating Temperature -55 to 125 °C
tr, tf
Input Rise and Fall Time VCC = 2.0V 0 to 1000 ns
VCC = 4.5V 0 to 500 ns
VCC = 6.0V 0 to 400 ns
Cx External Capacitor NO LIMITATION pF
Rx External Resistor Vcc < 3V 5K to 1M Ω
Vcc > 3V 1K to 1M
M74HC123
6/12
DC SPE CIFICATI ONS
(1) : Per Circuit
Symbol Parameter
Test Condition Value
Unit
VCC
(V)
TA = 25°C -40 to 85°C -55 to 125°C
Min. Typ. Max. Min. Max. Min. Max.
VIH High Level Input
Voltage 2.0 1.5 1.5 1.5 V4.5 3.15 3.15 3.15
6.0 4.2 4.2 4.2
VIL Low Level Input
Voltage 2.0 0.5 0.5 0.5 V4.5 1.35 1.35 1.35
6.0 1.8 1.8 1.8
VOH High Level Output
Voltage 2.0 IO=-20 µA1.9 2.0 1.9 1.9
V
4.5 IO=-20 µA4.4 4.5 4.4 4.4
6.0 IO=-20 µA5.9 6.0 5.9 5.9
4.5 IO=-4.0 mA 4.18 4.31 4.13 4.10
6.0 IO=-5.2 mA 5.68 5.8 5.63 5.60
VOL Low Level Output
Voltage 2.0 IO=20 µA0.0 0.1 0.1 0.1
V
4.5 IO=20 µA0.0 0.1 0.1 0.1
6.0 IO=20 µA0.0 0.1 0.1 0.1
4.5 IO=4.0 mA 0.17 0.26 0.33 0.40
6.0 IO=5.2 mA 0.18 0.26 0.33 0.40
IIInput Leakage
Current 6.0 VI = VCC or GND ± 0.1 ± 1 ± 1 µA
ICC Quiescent Supply
Current 6.0 VI = VCC or GND 44080µA
I
CC’ Active State
Supply Current (1) 2.0 VI = VCC or GND
Pin 7 or 15
VIN = VCC/2
45 200 260 320 µA
4.5 500 600 780 960 µA
6.0 0.7 1 1.3 1.6 mA
M74HC123
7/12
AC EL ECTRI CAL CHARACTERISTICS (CL = 50 pF, Input tr = tf = 6ns)
CAPACITIVE CHARACT ERISTICS
1) C PD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without
load. (Refer to Test Circuit). Average operating current can be obtained by t he following equation. ICC(opr) = CPD x VCC x fIN + I CC’ Duty/100
+ Ic/2(per monostable) (Icc’ : Active Supply current) (Duty : %)
Symbol Parameter
Test Condition Value
Unit
VCC
(V)
TA = 25°C -40 to 85°C -55 to 125°C
Min. Typ. Max. Min. Max. Min. Max.
tTLH tTHL Output Transition
Time 2.0 30 75 95 110 ns4.5 8151922
6.0 7131619
t
PLH tPHL Propagation Delay
Time
(A, B - Q, Q)
2.0 102 210 265 315 ns4.5 29 42 53 63
6.0 22 36 45 54
tPLH tPHL Propagation Delay
Time(CLR
TRIGGER - Q, Q)
2.0 102 235 295 355 ns4.5 31 47 59 71
6.0 23 40 50 60
tPLH tPHL Propagation Delay
Time
(CLR - Q, Q)
2.0 68 160 200 240 ns4.5 20 32 40 48
6.0 16 27 34 41
tWOUT Output Pulse Width 2.0 Cx = 100 pF
Rx = 10KΩ
1.4 µs4.5 1.2
6.0 1.1
2.0 Cx = 0.1µF
Rx = 100KΩ
4.6 ms4.5 4.4
6.0 4.3
∆tWOUT Output Pulse Width
Error Between
Circuits in Same
Package
±1
%
tW(H)
tW(L)
Minimum Pulse
Width 2.0 75 95 110 ns4.5 15 19 22
6.0 13 16 19
tW(L) Minimum Pulse
Width (CLR)2.0 75 95 110 ns4.5 15 19 22
6.0 13 16 19
trr Minimum Retrigger
Time 2.0 Cx = 100 pF
Rx = 10KΩ
325 ns4.5 108
6.0 78
2.0 Cx = 0.1µF
Rx = 100KΩ
5µs4.5 1.4
6.0 1.2
Symbol Parameter
Test Condition Value
Unit
VCC
(V)
TA = 25°C -40 to 85°C -55 to 125°C
Min. Typ. Max. Min. Max. Min. Max.
CIN Input Capacitance 5.0 5101010pF
C
PD Power Dissipation
Capacitance (note
1) 5.0 162 pF
M74HC123
8/12
TEST CIRCUIT
CL = 50p F or equiva l ent (i nclud es ji g and probe capacitanc e)
RT = ZOUT of pulse ge nerator (typically 50Ω)
WAVEFORM : SWITCIHNG CHARACTERISTICS TEST WAVEFORM (f=1MHz; 50% duty cycle)
M74HC123
9/12
DIM. mm. inch
MIN. TYP MAX. MIN. TYP. MAX.
a1 0.51 0.020
B 0.77 1.65 0.030 0.065
b 0.5 0.020
b1 0.25 0.010
D 20 0.787
E 8.5 0.335
e 2.54 0.100
e3 17.78 0.700
F 7.1 0.280
I 5.1 0.201
L 3.3 0.130
Z 1.27 0.050
Plastic DIP-16 (0.25) MECHANICAL DAT A
P001C
M74HC123
10/12
DIM. mm. inch
MIN. TYP MAX. MIN. TYP. MAX.
A 1.75 0.068
a1 0.1 0.2 0.003 0.007
a2 1.65 0.064
b 0.35 0.46 0.013 0.018
b1 0.19 0.25 0.007 0.010
C 0.5 0.019
c1 45° (typ.)
D 9.8 10 0.385 0.393
E 5.8 6.2 0.228 0.244
e 1.27 0.050
e3 8.89 0.350
F 3.8 4.0 0.149 0.157
G 4.6 5.3 0.181 0.208
L 0.5 1.27 0.019 0.050
M 0.62 0.024
S8° (max.)
SO-16 MECHANICAL DATA
PO13H
M74HC123
11/12
DIM. mm. inch
MIN. TYP MAX. MIN. TYP. MAX.
A 1.2 0.047
A1 0.05 0.15 0.002 0.004 0.006
A2 0.8 1 1.05 0.031 0.039 0.041
b 0.19 0.30 0.007 0.012
c 0.09 0.20 0.004 0.0089
D 4.9 5 5.1 0.193 0.197 0.201
E 6.2 6.4 6.6 0.244 0.252 0.260
E1 4.3 4.4 4.48 0.169 0.173 0.176
e 0.65 BSC 0.0256 BSC
K0° 8°0° 8°
L 0.45 0.60 0.75 0.018 0.024 0.030
TSSOP16 MECHANICAL DATA
cE
b
A2
A
E1
D
1
PIN 1 IDENTIFICATION
A1 L
K
e
0080338D
M74HC123
12/12
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