74HCT4538DB-T [NXP]
IC HCT SERIES, DUAL MONOSTABLE MULTIVIBRATOR, PDSO16, PLASTIC, SSOP-16, Prescaler/Multivibrator;
| 型号： | 74HCT4538DB-T |
| 厂家： | 
NXP |
| 描述： | IC HCT SERIES, DUAL MONOSTABLE MULTIVIBRATOR, PDSO16, PLASTIC, SSOP-16, Prescaler/Multivibrator 时钟 光电二极管 逻辑集成电路 |
| 文件： | 总13页 (文件大小：141K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
INTEGRATED CIRCUITS
DATA SHEET
For a complete data sheet, please also download:
• The IC06 74HC/HCT/HCU/HCMOS Logic Family Specifications
• The IC06 74HC/HCT/HCU/HCMOS Logic Package Information
• The IC06 74HC/HCT/HCU/HCMOS Logic Package Outlines
74HC/HCT4538
Dual retriggerable precision
monostable multivibrator
September 1993
Product specification
File under Integrated Circuits, IC06
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
trigger/retrigger input (nA1) , an overriding active LOW
direct reset input (nRD), an output (nQ) and its complement
(nQ), and two pins (nCTC and nRCTC) for connecting the
external timing components Ct and Rt. Typical pulse width
variation over temperature range is ± 0.2%.
FEATURES
• Separate reset inputs
• Triggering from leading or trailing edge
• Output capability: standard
• ICC category: MSI
The “4538” may be triggered by either the positive or the
negative edges of the input pulse. The duration and
accuracy of the output pulse are determined by the
external timing components Ct and Rt. The output pulse
width (T) is equal to 0.7 × Rt × Ct. The linear design
techniques guarantee precise control of the output pulse
width.
• Power-on reset on-chip
GENERAL DESCRIPTION
The 74HC/HCT4538 are high-speed Si-gate CMOS
devices and are pin compatible with “4538” of the “4000B”
series. They are specified in compliance with JEDEC
standard no. 7A.
A LOW level at nRD terminates the output pulse
immediately.
The 74HC/HCT4538 are dual retriggerable-resettable
monostable multivibrators. Each multivibrator has an
active LOW trigger/retrigger input (nA0), an active HIGH
Schmitt-trigger action in the trigger inputs makes the circuit
highly tolerant to slower rise and fall times.
QUICK REFERENCE DATA
GND = 0 V; Tamb = 25 °C; tr = tf = 6 ns
TYPICAL
SYMBOL
PARAMETER
CONDITIONS
UNIT
ns
HC
HCT
30
tPHL/ tPLH
CI
propagation delay nA0, nA1 to nQ, nQ
input capacitance
CL = 15 pF; VCC = 5 V 27
3.5
3.5
pF
pF
CPD
power dissipation capacitance per multivibrator notes 1 and 2
136
138
Notes
1.
C
PD is used to determine the dynamic power dissipation (PD in µW):
PD = CPD × VCC2 × fi + ∑ (CL × VCC2 × fo) +
+ 0.48 × CEXT × VCC2 × fo + D × 0.8 × VCC where:
fi = input frequency in MHz
fo = output frequency in MHz
∑ (CL × VCC2 × fo) = sum of outputs
CL = output load capacitance in pF
V
CC = supply voltage in V
D = duty factor in %
CEXT = timing capacitance in pF
2. For HC the condition is VI = GND to VCC
For HCT the condition is VI = GND to VCC − 1.5 V
ORDERING INFORMATION
See “74HC/HCT/HCU/HCMOS Logic Package Information”.
September 1993
2
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
PIN DESCRIPTION
PIN NO.
1, 15
2, 14
3, 13
4, 12
5, 11
6, 10
7, 9
SYMBOL
1CTC, 2CTC
1RCTC, 2RCTC
1RD, 2RD
1A1, 2A1
1A0, 2A0
1Q, 2Q
NAME AND FUNCTION
external capacitor connections
external resistor/capacitor connections
direct reset inputs (active LOW)
trigger inputs (LOW-to-HIGH, edge-triggered)
trigger inputs (HIGH-to-LOW, edge-triggered)
pulse outputs
1Q, 2Q
complementary pulse outputs
ground (0 V)
8
GND
16
VCC
positive supply voltage
Fig.1 Pin configuration.
Fig.2 Logic symbol.
Fig.3 IEC logic symbol.
September 1993
3
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
FUNCTION TABLE
INPUTS
nA1
OUTPUTS
nA0
nRD
nQ
nQ
↓
L
H
H
↑
H
L
X
X
L
H
Notes
1. H = HIGH voltage level
L = LOW voltage level
X = don’t care
↑
↓
= LOW-to-HIGH transition
= HIGH-to-LOW transition
Fig.4 Functional diagram.
= one HIGH level output pulse
= one LOW level output pulse
(1) Connect CTC (pins 1 and 15) to GND (pin 8).
Fig.5 Connection of the external timing
components Rt and Ct.
(1) Positive edge triggering.
(2) Positive edge retriggering (pulse
lengthening).
(3) Negative edge triggering.
(4) Reset (pulse shortening).
(5) Vref1 and Vref2 are internal reference voltages.
(6) T = 0.7 × Rt × Ct (see also Fig.5).
Fig.6 Timing diagram.
September 1993
4
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
nA
1
nA
0
V
CC
power - on reset
V
CC
nRC
TC
enable
V
ref1
nQ
nQ
nC
TC
GND
nR
D
V
ref2
enable
MBA338
bnok,lfuapgedwith
Fig.7 Logic diagram (Vref1 and Vref2 are internal reference voltages).
September 1993
5
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
DC CHARACTERISTICS FOR 74HC
For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications”.
Output capability: standard
ICC category: MSI
AC CHARACTERISTICS FOR 74HC
GND = 0 V; tr = tf = 6 ns; CL = 50 pF
Tamb (°C)
TEST CONDITIONS
74HC
SYMBOL
PARAMETER
UNIT
VCC
(V)
+25
−40 to +85
−40 to +125
OTHER
min. typ. max. min. max. min. max.
tPLH
tPHL
tPHL
tPLH
propagation delay
nA0, nA1 to nQ
85
31
25
265
53
45
330
66
56
400
80
68
ns
ns
ns
ns
ns
ns
ns
ns
2.0 Fig.8
4.5
6.0
propagation delay
nA0, nA1 to nQ
83
30
24
265
53
45
330
66
56
400
80
68
2.0 Fig.8
4.5
6.0
propagation delay
nRD to nQ
80
29
23
265
53
45
330
66
56
400
80
68
2.0 Fig.8
4.5
6.0
propagation delay
nRD to nQ
83
30
24
265
53
45
340
68
58
400
80
68
2.0 Fig.8
4.5
6.0
t
THL/ tTLH
output transition
time
19
7
6
75
15
13
95
19
16
110
22
19
2.0 Fig.8
4.5
6.0
tW
nA0 pulse width
LOW
80
16
14
17
6
5
100
20
17
120
24
20
2.0 Fig.8
4.5
6.0
tW
nA1 pulse width
HIGH
80
16
14
17
6
5
100
20
17
120
24
20
2.0 Fig.8
4.5
6.0
tW
nRD pulse width
LOW
80
16
14
19
7
6
100
20
17
120
24
20
2.0 Fig.8
4.5
6.0
tW
nQ, nQ pulse width 0.63 0.70
HIGH or LOW
0.77 0.602 0.798 0.595 0.805 ms
5.0 Fig.8;
Rt = 10 kΩ;
Ct = 0.1 µF
2.0 Fig.8
4.5
6.0
trem
removal time
35
7
6
2
2
45
9
55
11
9
ns
RD to nA0, nA1
6
8
September 1993
6
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
T
amb (°C)
TEST CONDITIONS
74HC
SYMBOL
PARAMETER
UNIT
VCC
(V)
+25
−40 to +85
−40 to +125
OTHER
min. typ. max. min. max. min. max.
trt
retrigger time
nA0, nA1
−
−
−
455+X
80+X
55+X
−
−
−
−
−
−
ns
2.0 Fig.8
4.5 X = CEXT
6.0 (4.5 × VCC
/
)
REXT
CEXT
external timing
resistor
10
2
1000
1000
kΩ
2.0
5.0
external timing
capacitor
pF
5.0
no limits
NON-STANDARD DC CHARACTERISTICS FOR 74HC
Voltages are referenced to GND (ground = 0 V)
T
amb (°C)
TEST CONDITIONS
OTHER
74HC
SYMBOL
±II
PARAMETER
UNIT
VCC
(V)
VI
+25
min. typ max. min. max. min. max.
0.5 5.0 10.0 µA
−40 to +85 −40 to +125
(V)
input leakage current
nRCEXT
6.0
2.0
or
VCC or GND;
note 1
GND
Note
1. This measurement can only be carried out after a trigger pulse is applied.
September 1993
7
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
DC CHARACTERISTICS FOR 74HCT
For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications”.
Output capability: standard
ICC category: MSI
Note to HCT types
The value of additional quiescent supply current (∆ICC) for a unit load of 1 is given in the family specifications.
To determine ∆ICC per input, multiply this value by the unit load coefficient shown in the table below.
INPUT
UNIT LOAD COEFFICIENT
nA0, nA1
nRD
0.50
0.65
AC CHARACTERISTICS FOR 74HCT
GND = 0 V; tr = tf = 6 ns; CL = 50 pF
Tamb (°C)
74HCT
TEST CONDITIONS
OTHER
SYMBOL PARAMETER
UNIT
VCC
+25
−40 to +85
−40 to +125
(V)
min. typ. max. min. max. min. max.
tPLH
tPHL
tPHL
tPLH
propagation delay
nA0, nA1 to nQ
35
35
35
35
7
60
60
60
60
15
75
75
75
75
19
90
90
90
90
21
ns
ns
ns
ns
ns
ns
ns
ns
4.5 Fig.8
4.5 Fig.8
4.5 Fig.8
4.5 Fig.8
4.5 Fig.8
4.5 Fig.8
4.5 Fig.8
4.5 Fig.8
propagation delay
nA0, nA1 to nQ
propagation delay
nRD to nQ
propagation delay
nRD to nQ
t
THL/ tTLH output transition time
tW
tW
tW
tW
trem
trt
nA0 pulse width
LOW
20
16
20
11
5
25
20
25
30
24
30
nA1 pulse width
HIGH
nRD pulse width
LOW
11
nQ, nQ pulse width
HIGH or LOW
0.63 0.70 0.77 0.602 0.798 0.595 0.805 ms
5.0 Fig.8; Rt = 10 kΩ;
Ct = 0.1 µF
removal time
RD to nA0, nA1
7
2
9
11
ns
ns
4.5 Fig.8
retrigger time
nA0, nA1
−
80+X
−
−
4.5 Fig.8
X = CEXT
/
(4.5 × VCC
)
REXT
CEXT
external timing
resistor
2
1000
kΩ
5.0
5.0
external timing
capacitor
pF
no limits
8
September 1993
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
NON-STANDARD DC CHARACTERISTICS FOR 74HCT
Voltages are referenced to GND (ground = 0 V)
Tamb (°C)
TEST CONDITIONS
74HCT
SYMBOL
±II
PARAMETER
UNIT
OTHER
VCC VI
(V) (V)
+25
min. typ max. min. max. min. max.
0.5 5.0 10.0 µA
−40 to +85 −40 to +125
input leakage current
nRCEXT
5.5 2.0
or
VCC or GND;
note 1
GND
Note
1. This measurement can only be carried out after a trigger pulse is applied.
AC WAVEFORMS
(1) HC : VM = 50%; VI = GND to VCC
.
HCT: VM = 1.3 V; VI = GND to 3 V.
Fig.8 Waveforms showing the input (nA1, nA0, nRD) to output (nQ, nQ) propagation delays, the output transition
times, the input and output pulse widths, the removal time from direct reset (nRD) to input (nA1, nA0), and
the input retrigger time.
September 1993
9
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
APPLICATION INFORMATION
(a)
(b)
Fig.9 Retriggerable monostable circuitry.
(a) rising-edge triggered; (b) falling-edge triggered.
(a)
(b)
Fig.10 Non-retriggerable monostable circuitry.
(a) rising-edge triggered; (b) falling-edge triggered.
September 1993
10
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
Power-down considerations
A large capacitor (CX) may cause problems when
powering-down the monostable due to the energy stored
in this capacitor. When a system containing this device is
powered-down or a rapid decrease of VCC to zero occurs,
the monostable may sustain damage, due to the capacitor
discharging through the input protection diodes. To avoid
this possibility, use a damping diode (DX) preferably a
germanium or Schottky type diode able to withstand large
current surges and connect as shown in Fig.11.
Fig.11 Power-down protection circuit.
Fig.12 Typical pulse width accuracy versus external capacitance; VCC = 4.5 V; Tamb = 25 °C.
Fig.13 Typical pulse width accuracy versus external resistance; VCC = 4.5 V; Tamb = 25 °C.
September 1993
11
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
Fig.14 Typical pulse width accuracy versus external capacitance; REXT = 10 kΩ; VCC = 4.5 V; Tamb = 25 °C.
Fig.15 Typical pulse width accuracy versus power supply; CEXT = 1 nF; Tamb = 25 °C.
Fig.16 Typical pulse width accuracy versus power supply; CEXT = 100 nF; Tamb = 25 °C.
September 1993
12
Philips Semiconductors
Product specification
Dual retriggerable precision monostable
multivibrator
74HC/HCT4538
Fig.17 Typical pulse width accuracy versus temperature; CEXT = 1 nF; VCC = 4.5 V.
Fig.18 Typical pulse width accuracy versus temperature; CEXT = 1 µF; VCC = 4.5 V.
PACKAGE OUTLINES
See “74HC/HCT/HCU/HCMOS Logic Package Outlines”.
September 1993
13
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