STMICROELECTRONICS M74HC4538TTR

M74HC4538
Dual retriggerable monostable multivibrator
Features
■
High speed:
tPD = 25 ns (typ.) at VCC = 6 V
■
Low power dissipation
standby state:
ICC = 4 μA (max.) at TA = 25 °C
active state:
ICC = 200 μA (max.) at VCC = 6 V
■
High noise immunity:
VNIH = VNIL = 28 % VCC (min.)
■
Symmetrical output impedance:
|IOH| = IOL = 4 mA (min.)
■
Balanced propagation delays:
tPLH ≅ tPHL
■
Wide operating voltage range:
VCC (opr) = 2 to 6 V
■
Wide output pulse width range:
tWOUT = 120 ns ~ 60 s over at VCC = 4.5 V
■
Pin and function compatible with
74 series 4538
SO-16
DIP-16
TSSOP16
Description
The M74HC4538 is a high speed CMOS monostable
multivibrator fabricated with silicon gate C2MOS
technology.
Each multivibrator features both a negative A, and a
positive B, edge triggered input, either of which can be
used as an inhibit input. Also included is a clear input
that when taken low resets the one shot. The
monostable multivibrators are retriggerable. That is,
they may be triggered repeatedly while their outputs are
generating a pulse and the pulse will be extended.
Pulse width stability over a wide range of temperature
and supply is achieved using linear CMOS techniques.
The output pulse equation is simply: PW = 0.7 (R)(C)
where PW is in seconds, R in Omhs and C is in Farads.
All the inputs are equipped with protection circuits
against static discharge and transient excess voltage.
Table 1.
Device summary
Order code
Package
Packaging
M74HC4538B1R
DIP-16
Tube
M74HC4538RM13TR
SO-16
Tape and reel
M74HC4538TTR
TSSOP16
Tape and reel
May 2008
Rev 2
1/18
www.st.com
18
Pin connection and IEC logic symbols
1
Pin connection and IEC logic symbols
Figure 1.
Pin connections and IEC logic symbols
Inputs
Outputs
Table 2.
2/18
M74HC4538
1T1
1
16
VCC
1T2
2
15
2T1
1CD
3
14
2T2
1A
4
13
2CD
1B
5
12
2A
Q1
6
11
2B
Q1
7
10
Q2
GND
8
9
Q2
Inputs
Outputs
Pin description
Pin number
Symbol
Name and function
1, 15
1T1, 2T1
External capacitor connections
2, 14
1T2, 2T2
External resistor, capacitor connections
3, 13
1CD, 2CD
Direct reset inputs (active low)
4, 12
1A, 2A
Trigger inputs (low to high, edge-triggered)
5, 11
1B, 2B
Trigger inputs (high to low, edge-triggered)
6, 10
Q1, Q2
Pulse outputs
7, 9
Q1, Q2
Complementary pulse outputs
8
GND
Ground (0 V)
16
VCC
Positive supply voltage
M74HC4538
Pin connection and IEC logic symbols
Figure 2.
Input and output equivalent circuit
VCC
VCC
Output
Input
GND
Table 3.
GND
Truth table
Inputs
Outputs
Note
B
CD
H
H
X
L
H
L
H
Inhibit
H
X
H
L
H
Inhibit
A
L
X
Figure 3.
Q
Q
Output enable
H
X
L
Output enable
L
H
Inhibit
System diagram
3/18
Pin connection and IEC logic symbols
Figure 4.
Timing chart
Figure 5.
Block diagram
M74HC4538
1. Cx, Rx, Dx are external components.
2. Dx is a clamping diode.
The external capacitor is charged to VCC in the standby state, i.e. no trigger. When the supply voltage is
turned off Cx is discharged mainly through an internal parasitic diode (see figures). If Cx is sufficiently large
and VCC decreases rapidly, there will be some possibility of damaging the IC with a surge current or latchup. If the voltage supply filter capacitor is large enough and VCC decreases slowly, the surge current is
automatically limited and damage to the IC is avoided. The maximum forward current of the parasitic diode
is approximately 20 mA. In cases 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/20 mA.
In cases where tf is too short an external clamping diode is required to protect the IC from the surge
current.
4/18
M74HC4538
2
Functional description
Functional description
Standby state
The external capacitor Cx, is fully charged to VCC in the standby 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 only leakage current.
Trigger operation
Triggering occurs when:
–
A is low and B has a falling edge
–
B is high and A has a rising edge
After the multivibrator has been retriggered, the comparator C1 and C2 start operating and
Qn is turned on. Cx then discharges through Qn. The voltage at the node Rx/Cx external
falls.
When it reaches VREFL the output of comparator C1 becomes low. This in turn resets the
flip-flop and Qn is turned off.
At this point C1 stops functioning but C2 continues to operate.
The voltage at R/C external begins to rise with a time constant set by the external
components Rx and 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 G goes low. C2 stops 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 the delay time in the IC can be ignored, the width of the output pulse tw(out) is
as follows:
t W( OUT ) = 0.72Cx • Rx
Re-triggered operation
When a second triggered pulse follows the first, its effect will depend on the state of the
multivibrator. If the capacitor Cx is being charged, the voltage level of Rx/Cx external falls to
VREFL again and Q remains high i.e. the retrigger pulse arrives in a time shorter than the
period Rx · Cx seconds, the capacitor charging time constant. If the second trigger pulse is
very close to the initial trigger pulse it is ineffective; i.e. the second trigger must arrive in the
capacitor discharge cycle to be ineffective; hence the minimum time for a second trigger to
be effective, trr (min.) depends on VCC and Cx.
Reset operation
CD is normally high. If CD is low, the trigger is not effective because Q output goes low and
trigger control flip-flop is reset. Also transistor Op is turned on and Cx is charged quickly to
VCC. Then, if CD input goes low the IC becomes waiting state both in operating and non
operating state.
5/18
Maximum rating
3
M74HC4538
Maximum rating
Stressing the device above the rating listed in the “Absolute maximum ratings” table may
cause permanent damage to the device. These are stress ratings only, and operation of the
device at these or any other conditions above those indicated in the operating sections of
this specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability. Refer also to the STMicroelectronics SURE
Program and other relevant quality documents.
Table 4.
Absolute maximum ratings
Symbol
VCC
Parameter
Supply voltage
Value
Unit
-0.5 to +7
V
VI
DC input voltage
-0.5 to VCC + 0.5
V
VO
DC output voltage
-0.5 to VCC + 0.5
V
IIK
DC input diode current
± 20
mA
IOK
DC output diode current
± 20
mA
IO
DC output current
± 25
mA
DC VCC or ground current
± 50
mA
500(1)
mW
-65 to +150
°C
300
°C
Value
Unit
2 to 6
V
ICC or
IGND
PD
Power dissipation
Tstg
Storage temperature
TL
Lead temperature (10 sec)
1. 500 mW at 65 ° C; derate to 300 mW by 10 mW/ ° C from 65° C to 85° C
3.1
Recommended operating conditions
Table 5.
Recommended operating conditions
Symbol
VCC
Supply voltage
VI
Input voltage
0 to VCC
V
VO
Output voltage
0 to VCC
V
Top
Operating temperature
-55 to 125
°C
VCC = 2.0 V
0 to 1000
ns
VCC = 4.5 V
0 to 500
ns
VCC = 6.0 V
0 to 400
ns
No limitation
pF
tr, tf
6/18
Parameter
Input rise and fall time (CD only)
Cx
External capacitor
Rx
External resistor
VCC ≤3.0 V
5 K to 1 M
VCC ≥ 3.0 V
1 K to 1 M
Ω
M74HC4538
Electrical characteristics
4
Electrical characteristics
Table 6.
DC specifications
Test condition
Symbol
Parameter
Value
TA = 25°C
VCC
(V)
Min
VIH
VIL
VOH
VOL
High level input
voltage
Low level input
voltage
High level output
voltage
Low level output
voltage
Typ
-40 to 85°C
Max
Min
Max
-55 to
125°C
Min
2.0
1.5
1.5
1.5
4.5
3.15
3.15
3.15
6.0
4.2
4.2
4.2
Unit
Max
V
2.0
0.5
0.5
0.5
4.5
1.35
1.35
1.35
6.0
1.8
1.8
1.8
2.0
IO = -20 μA
1.9
2.0
1.9
1.9
4.5
IO = -20 μA
4.4
4.5
4.4
4.4
6.0
IO = -20 μA
5.9
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
2.0
IO = 20 μA
0.0
0.1
0.1
0.1
4.5
IO = 20 μA
0.0
0.1
0.1
0.1
6.0
IO = 20 μA
0.0
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
V
V
V
II
Input leakage
current
6.0
VI = VCC or GND
± 0.1
±1
±1
μA
II
Input leakage
current
6.0
VI = VCC or GND
Rext/Cext
± 0.1
±1
±1
μA
ICC
Quiescent supply
current
6.0
VI = VCC or GND
4
40
80
μA
40
120
160
200
μA
ICC
Quiescent supply
current
0.2
0.3
0.4
0.6
mA
0.3
0.6
0.8
1.0
mA
2.0
4.5
6.0
VI = VCC or GND
Pin 2 or 14
VIN = VCC/2
7/18
Electrical characteristics
Table 7.
M74HC4538
AC electrical characteristics (CL = 50 pF, Input tr = tf = 6 ns)
Test condition
Symbol
Parameter
Value
TA = 25°C
VCC
(V)
Min
tTLH tTHL
tPLH tPHL
tPLH tPHL
Output transition
time
Propagation
delay time
(A, B - Q, Q)
Propagation
delay time
(CD - Q, Q)
Max
2.0
30
75
95
110
4.5
8
15
19
22
6.0
7
13
16
19
2.0
120
250
315
375
4.5
30
50
63
75
6.0
25
43
54
64
2.0
100
195
245
295
4.5
25
39
49
59
6.0
20
33
42
50
Rx = 5 KΩ
540
1200
1500
1800
Rx = 1 KΩ
180
250
320
375
Rx = 1 KΩ
150
200
260
320
70
83
96
70
96
70
96
69
77
85
69
85
69
85
69
77
85
69
85
69
85
0.67
0.75
0.83
0.67
0.83
0.67
0.9
0.67
0.73
0.77
0.67
0.77
0.67
0.8
0.67
0.73
0.77
0.67
0.77
0.67
0.8
4.5
6.0
Cx=0
2.0
tWOUT
4.5
Cx = 0.01 μF
Rx = 10 KΩ
6.0
2.0
4.5
6.0
ΔtWOUT
Output pulse
width error
between circuits
in same package
Minimum pulse
tW(H) tW(L) width
(A,B)
tW(L)
tREM
8/18
Minimum pulse
width
(CD)
Minimum clear
removal time
Cx = 0.1 μF
Rx = 10 KΩ
Min
Max
-55 to
125°C
Typ
2.0
Output pulse
width
-40 to 85°C
Min
Unit
Max
±1
ns
ns
ns
ns
μs
ms
%
2.0
30
75
95
110
4.5
8
15
19
22
6.0
7
13
16
19
2.0
30
75
95
110
4.5
8
15
19
22
6.0
7
13
16
19
2.0
0
15
15
20
4.5
0
5
5
7
6.0
0
5
5
ns
ns
ns
M74HC4538
Table 7.
Electrical characteristics
AC electrical characteristics (CL = 50 pF, Input tr = tf = 6 ns) (continued)
Test condition
Symbol
Parameter
Value
TA = 25°C
VCC
(V)
Min
Typ
Cx = 0.1 μF
Rx = 1KΩ
4.5
Minimum
retrigger time
Min
Unit
Max
ns
72
6
2.0
Cx = 0.01μF
Rx = 1KΩ
μs
1.4
6.0
1.2
Capacitive characteristics
Test condition
Symbol
Max
92
6.0
4.5
Table 8.
Min
-55 to
125°C
380
2.0
trr
Max
-40 to 85°C
Parameter
VCC
(V)
Value
TA = 25°C
Min
-40 to 85°C
Typ
Max
10
CIN
Input capacitance
5.0
5
CPD
Power dissipation
capacitance (1)
5.0
70
Min
Max
10
-55 to 125°C
Min
Unit
Max
10
pF
pF
1. CPD 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 the following equation.
ICC(opr) = CPD x VCC x fIN + ICC’ Duty/100 + Ic/2(per monostable) (Icc’ : Active Supply current) (Duty : %)
9/18
Electrical characteristics
10/18
M74HC4538
Figure 6.
Test circuit
Figure 7.
Waveform: propagation delay times (f = 1 MHz; 50% duty cycle)
M74HC4538
5
Package mechanical data
Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a Lead-free second level interconnect. The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.
11/18
Package mechanical data
M74HC4538
Plastic DIP-16 (0.25) MECHANICAL DATA
mm.
inch
DIM.
MIN.
a1
0.51
B
0.77
TYP
MAX.
MIN.
TYP.
MAX.
0.020
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
Z
3.3
0.130
1.27
0.050
P001C
12/18
M74HC4538
Package mechanical data
SO-16 MECHANICAL DATA
DIM.
mm.
MIN.
TYP
A
a1
inch
MAX.
MIN.
TYP.
1.75
0.1
0.25
a2
0.004
0.010
0.46
0.013
0.018
0.25
0.007
1.64
b
0.35
b1
0.19
C
MAX.
0.068
0.063
0.5
0.010
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
e3
8.89
F
3.8
0.050
0.350
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
S
0.62
0.024
8° (max.)
0016020D
13/18
Package mechanical data
M74HC4538
TSSOP16 MECHANICAL DATA
mm.
inch
DIM.
MIN.
TYP
A
MIN.
MAX.
TYP.
MAX.
1.2
A1
0.05
A2
0.8
b
0.047
0.15
0.002
0.004
0.006
1.05
0.031
0.039
0.041
0.19
0.30
0.007
0.012
c
0.09
0.20
0.004
0.0079
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
1
e
0.65 BSC
K
0°
L
0.45
A
0.60
0.0256 BSC
8°
0°
0.75
0.018
8°
0.024
0.030
A2
A1
b
e
K
c
L
E
D
E1
PIN 1 IDENTIFICATION
1
0080338D
14/18
M74HC4538
Package mechanical data
Tape & Reel SO-16 MECHANICAL DATA
mm.
inch
DIM.
MIN.
A
TYP
MAX.
MIN.
C
12.8
D
20.2
0.795
N
60
2.362
T
MAX.
12.992
330
13.2
TYP.
0.504
22.4
0.519
0.882
Ao
6.45
6.65
0.254
0.262
Bo
10.3
10.5
0.406
0.414
Ko
2.1
2.3
0.082
0.090
Po
3.9
4.1
0.153
0.161
P
7.9
8.1
0.311
0.319
15/18
Package mechanical data
M74HC4538
Tape & Reel TSSOP16 MECHANICAL DATA
mm.
inch
DIM.
MIN.
A
MAX.
MIN.
13.2
TYP.
MAX.
12.992
330
C
12.8
D
20.2
0.795
N
60
2.362
T
16/18
TYP
0.504
22.4
0.519
0.882
Ao
6.7
6.9
0.264
0.272
Bo
5.3
5.5
0.209
0.217
Ko
1.6
1.8
0.063
0.071
Po
3.9
4.1
0.153
0.161
P
7.9
8.1
0.311
0.319
M74HC4538
6
Revision history
Revision history
Table 9.
Document revision history
Date
Revision
01-Jul-2001
1
Initial release.
2
Document converted and restructured to new template.
Removed: M74HC4538M1R order code.
Minor text changes.
Added: SO-16 and TSSOP16 tape and reel specifications.
26-May-2008
Changes
17/18
M74HC4538
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18/18