74HC4538 [STMICROELECTRONICS]
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATOR; 双可重触发单稳多谐振荡器
| 型号： | 74HC4538 |
| 厂家： | 
ST |
| 描述： | DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATOR |
| 文件： | 总14页 (文件大小：290K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
M54HC4538
M74HC4538
DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATOR
.
.
.
.
.
.
.
.
HIGH SPEED
tPD = 25 ns (TYP.) AT VCC = 5 V
LOW POWER DISSIPATION
STANDBY STATEICC =4µA(MAX.)ATTA =25°C
ACTIVE STATE ICC =200 µA (TYP.) AT VCC = 5 V
HIGH NOISE IMMUNITY
V
NIH = VNIL = 28 % VCC (MIN.)
B1R
F1R
OUTPUT DRIVE CAPABILITY
10 LSTTL LOADS
BALANCED PROPAGATION DELAYS
tPLH = tPHL
WIDE OUTPUT PULSE WIDTH RANGE
tWOUT = 120 ns ~ 60 s OVER AT VCC = 4.5 V
OUTPUT PULSE WIDTH INDEPENDENT
FROM TRIGGER INPUT PULSE WIDTH
PIN AND FUNCTION COMPATIBLE
WITH 4538B
(Plastic Package)
(Ceramic Package)
M1R
C1R
(Micro Package)
(Chip Carrier)
ORDER CODES :
M54HC4538F1R
M74HC4538M1R
M74HC4538B1R
M74HC4538C1R
PIN CONNECTIONS (top view)
DESCRIPTION
The M54/74HC4538 is a high speed CMOS DUAL
MONOSTABLEMULTIVIBRATOR fabricated insili-
con gate C2MOS technology. It has the same high
speed performance of LSTTL combined with true
CMOS low power consumption. Each multivibrator
features both a negative, A, and a positive, B, edge
triggered input, either of which can be used as an in-
hibit 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 reapeatedly while their outputs are gener-
ating 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
Ohms, and C is in Farads.
NC =
All inputs are equipped with protection circuits
against static discharge and transient excess volt-
age.
No Internal
Connection
October 1993
1/14
M54/M74HC4538
SYSTEM DIAGRAM
TIMING CHART
2/14
M54/M74HC4538
BLOCK DIAGRAM
Notes : 1. Cx, Rx, Dx areexternal components.
2. Dx is a clamping diode.
3. The external capacitor is charged to VCC inthe stand-by state, i.e. no trigger.When the supply voltage is turned offCx is discharged
mainlythrough aninternal parasitic diode(seefigures). IfCx issufficiently largeandVCC decreases rapidy, there willbesomepossibility
of damaging the I.C. with a surgecurrent or latch-up. If the voltage supply filter capacitor is large enough and VCC decrease slowly,
the surge current is automatically limitedand damage the I.C. is avoided. The maximum forward current of the parasitic diodeis ap-
proximately 20 mA. In cases where Cx is largethe time taken for the supply voltage to fall to 0.4 VCC can be calculated as follows :
tf ≥ (VCC – 0.7) Cx/20 mA
In cases where tf is too short an external champing diode is required to protect the I.C. from the surge current.
FUNCTIONAL DESCRIPTION
STAND-BY STATE
Triggering the multivibrator causes Qto go high after
internal delay due to the flip-flop and the gate. Q re-
mains high until the voltage at R/C external rises
again to VREFH. Atthis point C2 output goes low and
G goes low. C2 stops operating. That means that
after triggering when the voltage at R/C external re-
turns 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 ca-
pacitorand the delay time in the I.C. can be ignored,
the width of the output pulse tw (out) is as follows :
tW(OUT) = 0.72 Cx • Rx
The external capacitor, Cx, is fully charged to VCC
in the stand-by state. Hence, before triggering, tran-
sistorQp and Qn (connected to the Rx/Cx node) are
bothturned off. Thetwo 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 :
1 st) A is ”low” and B has a falling edge ;
2 nd) B is ”high” and A has a rising edge ;
RE-TRIGGER OPERATION
When a second trigger pulse follows the first its ef-
fect will depend on the state of the multivibrator. If
the capacitor Cx is being charged the voltage level
of Rx/Cx external falls toVREFL 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.
After the multivibrator has been retriggered com-
parator 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. ThevoltageatR/Cexternal beginstorise
with a time constant setby the external components
Rx, Cx.
Hence the minimum time for a second trigger to be
effective, trr (Min.) depends on VCC and Cx.
3/14
M54/M74HC4538
FUNCTIONAL DESCRIPTION (continued)
RESET OPERATION
Also transistor Op is turned on and Cx is charged
quicky to VCC. This means if CD input goes low, the
IC becomes waiting state both in operating and non
operating state.
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.
TRUTH TABLE
INPUTS
OUTPUTS
NOTE
A
B
H
L
CD
H
Q
Q
OUTPUT ENABLE
X
H
L
H
L
L
H
H
INHIBIT
INHIBIT
X
H
H
OUTPUT ENABLE
INHIBIT
X
X
L
L
H
INPUT AND OUTPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
IEC LOGIC SYMBOL
PIN No SYMBOL
NAME AND FUNCTION
1, 15
2, 14
3, 13
4, 12
5, 11
1T1, 2T1 External Capacitor
Connections
1T2, 2T2 External Resistor/Capacitor
Connections
1CD, 2CD Direct Reset Inputs (Active
LOW)
1A, 2A
Trigger Inputs (LOW to
HIGH, Edge-Triggered)
1B, 2B
Trigger Inputs (HIGH to
LOW, Edge-Triggered)
6, 10
7, 9
8
Q1, Q2
Q1, Q2
GND
Pulse Outputs
Complementary Pulse Outputs
Ground (0V)
16
VCC
Positive Supply Voltage
4/14
M54/M74HC4538
ABSOLUTE MAXIMUM RATINGS
Symbol
VCC
VI
Parameter
Value
Unit
Supply Voltage
-0.5 to +7
-0.5 to VCC + 0.5
-0.5 to VCC + 0.5
± 20
V
V
DC Input Voltage
VO
DC Output Voltage
V
IIK
DC Input Diode Current
DC Output Diode Current
DC Output Source Sink Current Per Output Pin
mA
mA
mA
mA
mW
oC
IOK
± 20
IO
± 25
ICC or IGND DC VCC or Ground Current
± 50
PD
Tstg
TL
Power Dissipation
500 (*)
Storage Temperature
Lead Temperature (10 sec)
-65 to +150
300
oC
Absolute MaximumRatingsare those values beyond whichdamage tothe device may occur. Functional operation under these condition isnotimplied.
(*) 500 mW: 65 oC derate to 300 mW by 10mW/oC: 65 oC to 85 oC
RECOMMENDED OPERATING CONDITIONS
Symbol
VCC
VI
Parameter
Value
2 to 6
Unit
V
Supply Voltage
Input Voltage
Output Voltage
0 to VCC
0 to VCC
V
VO
V
Top
Operating Temperature: M54HC Series
M74HC Series
-55 to +125
-40 to +85
oC
oC
tr, tf
Input Rise and Fall Time (CLR only)
VCC = 2 V
VCC = 4.5 V
VCC = 6 V
0 to 1000
0 to 500
ns
0 to 400
CX
RX
External Capacitor
External Resistor
NO LIMITATION (*)
5K to 1M (*)
1K to 1M (*)
VCC ≤ 3 V
Ω
VCC > 3 V
(*) The maximum allowable values of Cx and Rx are a function of leakage of capacitor Cx, the leakage of device and leakagedue to the board
layout and surface resistance. Susceptibility to externally induced noise may occur for Rx > 1MΩ
5/14
M54/M74HC4538
DC SPECIFICATIONS
Test Conditions
VCC
Value
TA = 25 oC
54HC and 74HC
-40 to 85 oC -55 to 125 oC
Symbol
Parameter
Unit
74HC
54HC
(V)
Min. Typ. Max. Min. Max. Min. Max.
VIH
High Level Input
Voltage
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
4.5
6.0
1.5
3.15
4.2
1.5
3.15
4.2
1.5
3.15
4.2
V
V
VIL
Low Level Input
Voltage
0.5
1.35
1.8
0.5
1.35
1.8
0.5
1.35
1.8
VOH
High Level
Output Voltage
1.9
4.4
5.9
2.0
4.5
6.0
1.9
4.4
1.9
4.4
VI =
VIH
or
IO=-20 µA
V
V
5.9
5.9
VIL
IO=-4.0 mA 4.18 4.31
4.13
5.63
4.10
5.60
IO=-5.2 mA 5.68
5.8
0.0
0.0
0.0
VOL
Low Level Output 2.0
Voltage
0.1
0.1
0.1
0.1
0.1
0.1
0.1
VI =
VIH
or
IO= 20 µA
4.5
6.0
4.5
6.0
0.1
0.1
VIL
IO= 4.0 mA
IO= 5.2 mA
0.17 0.26
0.18 0.26
±0.1
0.37
0.37
±1
0.40
0.40
±1
II
Input Leakage
6.0
VI = VCC or GND
µA
µA
µA
Current
II
Input Leakage
6.0
VI = VCC or GND
Rext/Cext
±0.1
±1
±1
Current
ICC
ICC
Quiescent Supply 6.0 VI = VCC or GND
Current
4
40
80
Quiescent Supply 2.0 VI = VCC or GND
40
0.2
0.3
120
0.3
0.6
160
0.4
0.8
µA
mA
mA
Current
pins 2, 14
VI = VCC/2
4.5
6.0
6/14
M54/M74HC4538
AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, Input tr = tf = 6 ns)
Test Conditions
Value
-40 to 85 oC -55 to 125 oC
74HC 54HC
TA = 25 oC
54HC and 74HC
Symbol
Parameter
Unit
VCC
(V)
Min. Typ. Max. Min. Max. Min. Max.
tTLH
tTHL
Output Transition
Time
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
30
8
75
15
95
19
110
22
ns
ns
ns
ns
µs
ms
7
13
16
19
tPLH
tPHL
Propagation
Delay Time
(A, B - Q, Q)
120
30
25
100
25
20
250
50
315
63
375
75
43
54
64
tPLH
tPHL
Propagation
Delay Time
(CD - Q, Q)
195
39
245
49
295
59
33
42
50
tWOUT
Output Pulse
Width
RX = 5KΩ
RX = 1KΩ
RX = 1KΩ
540 1200
1500
320
260
96
1800
375
320
96
CX = 0
180
150
83
250
200
96
70
69
69
70
69
69
70
69
69
CX = 0.01 µF
RX = 10KΩ
77
85
85
85
77
85
85
85
0.67 0.75 0.83 0.67 0.83 0.67
0.67 0.73 0.77 0.67 0.77 0.67
0.67 0.73 0.77 0.67 0.77 0.67
±1
0.9
0.8
0.8
CX = 0.1 µF
RX = 10KΩ
∆tWOUT Output Pulse
Width Error
%
ns
ns
ns
ns
µs
Between Circuits
(In same pack)
tW(H)
tW(L)
Minimum Pulse
Width
(CLOCK)
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
30
8
75
15
13
75
15
13
15
5
95
19
16
95
19
16
15
5
110
22
19
110
22
19
20
7
7
tW(L)
tREM
ts
Minimum Pulse
Width
(CLEAR)
30
8
7
Minimum Clear
Removal Time
0
0
0
5
5
Minimum
Retrigger Time
380
92
72
6
6
CX = 0.1 µF
RX = 1KΩ
CX = 0.01 µF
RX = 1KΩ
1.4
1.2
5
CIN
Input Capacitance
10
10
10
pF
pF
CPD (*) Power Dissipation
Capacitance
70
(*) CPD isdefined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without load.
(Refer toTest Circuit). Average operting current can be obtained by the followingequation. ICC(opr) = CPD •VCC • fIN +ICC‘ • Duty/100 + ICC/2 (per circuit)
(ICC‘ = ActiveSupply Current)
(Duty = %))
7/14
M54/M74HC4538
TEST CIRCUIT ICC (Opr.)
Output Pulse Width Constant K = Supply Voltage.
INPUT WAVEFORMIS THE SAME AS THAT IN CASE OF
SWITCHINGCHARACTERISTICS TEST.
tWOUT - Cx Characteristics (Typ).
trr - VCC Characteristics (Typ).
8/14
M54/M74HC4538
SWITCHING CHARACTERISTICS TEST WAVEFORM
9/14
M54/M74HC4538
Plastic DIP16 (0.25) MECHANICAL DATA
mm
inch
TYP.
DIM.
MIN.
TYP.
MAX.
MIN.
0.020
0.030
MAX.
a1
B
b
0.51
0.77
1.65
0.065
0.5
0.020
0.010
b1
D
E
e
0.25
20
0.787
8.5
2.54
17.78
0.335
0.100
0.700
e3
F
7.1
5.1
0.280
0.201
I
L
3.3
0.130
Z
1.27
0.050
P001C
10/14
M54/M74HC4538
Ceramic DIP16/1 MECHANICAL DATA
mm
inch
DIM.
MIN.
TYP.
MAX.
20
MIN.
TYP.
MAX.
0.787
0.276
A
B
7
D
E
3.3
0.130
0.700
0.38
0.015
e3
F
17.78
2.29
0.4
2.79
0.55
1.52
0.31
1.27
10.3
8.05
5.08
0.090
0.016
0.046
0.009
0.020
0.110
0.022
0.060
0.012
0.050
0.406
0.317
0.200
G
H
L
1.17
0.22
0.51
M
N
P
7.8
0.307
Q
P053D
11/14
M54/M74HC4538
SO16 (Narrow) MECHANICAL DATA
mm
inch
TYP.
DIM.
MIN.
TYP.
MAX.
1.75
0.2
MIN.
MAX.
0.068
0.007
0.064
0.018
0.010
A
a1
a2
b
0.1
0.004
1.65
0.46
0.25
0.35
0.19
0.013
0.007
b1
C
0.5
0.019
c1
D
45° (typ.)
9.8
5.8
10
0.385
0.228
0.393
0.244
E
6.2
e
1.27
8.89
0.050
0.350
e3
F
3.8
4.6
0.5
4.0
5.3
0.149
0.181
0.019
0.157
0.208
0.050
0.024
G
L
1.27
0.62
M
S
8° (max.)
P013H
12/14
M54/M74HC4538
PLCC20 MECHANICAL DATA
mm
inch
DIM.
MIN.
9.78
8.89
4.2
TYP.
MAX.
10.03
9.04
MIN.
0.385
0.350
0.165
TYP.
MAX.
0.395
0.356
0.180
A
B
D
4.57
d1
d2
E
2.54
0.56
0.100
0.022
7.37
8.38
0.290
0.330
0.004
e
1.27
5.08
0.38
0.050
0.200
0.015
e3
F
G
0.101
M
M1
1.27
1.14
0.050
0.045
P027A
13/14
M54/M74HC4538
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsability for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may results from its use. No
license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specificationsmentioned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied.
SGS-THOMSON Microelectronicsproductsare notauthorized foruse ascritical componentsin life support devices or systems without express
written approval of SGS-THOMSON Microelectonics.
1994 SGS-THOMSON Microelectronics - All Rights Reserved
SGS-THOMSON Microelectronics GROUP OF COMPANIES
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14/14
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