74HC4538-Q100
Rev. 3 — 17 March 2017
Dual retriggerable precision monostable multivibrator
Product data sheet
1
General description
The 74HC4538-Q100 is a dual retriggerable-resettable monostable multivibrator. Each
multivibrator has two trigger/retrigger inputs (nA and nB), a direct reset input (nCD),
two complementary outputs (nQ and nQ), and two pins (nREXT/CEXT and nCEXT)
for connecting the external timing components C
EXT
and R
EXT
. Typical pulse width
variation over temperature range is ± 0.2 %. The device 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 C
EXT
and R
EXT
. The output
pulse width (T
W
) is equal to 0.7 × R
EXT
× C
EXT
. The linear design techniques guarantee
precise control of the output pulse width. A LOW level at nCD terminates the output pulse
immediately. Schmitt-trigger action in the trigger inputs makes the circuit highly tolerant
to slower rise and fall times. Inputs include clamp diodes. This enables the use of current
limiting resistors to interface inputs to voltages in excess of V
CC
.
This product has been qualified to the Automotive Electronics Council (AEC) standard
Q100 (Grade 1) and is suitable for use in automotive applications.
2
Features and benefits
•
Automotive product qualification in accordance with AEC-Q100 (Grade 1)
–
Specified from -40 °C to +85 °C and from -40 °C to +125 °C
•
Tolerant of slow trigger rise and fall times
•
Separate reset inputs
•
Triggering from falling or rising edge
•
Complies with JEDEC standard no. 7A
•
CMOS input levels:
•
ESD protection:
–
MIL-STD-883, method 3015 exceeds 2000 V
–
HBM JESD22-A114F exceeds 2000 V
–
MM JESD22-A115-A exceeds 200 V
•
Multiple package options
Nexperia
Dual retriggerable precision monostable multivibrator
74HC4538-Q100
3
Ordering information
Package
Temperature
range
Name
SO16
Table 1. Ordering information
Type number
Description
plastic small outline package; 16 leads;
body width 3.9 mm
Version
SOT109-1
SOT403-1
74HC4538D-Q100
74HC4538PW-Q100
-40 °C to +125 °C
-40 °C to +125 °C
TSSOP16 plastic thin shrink small outline package; 16 leads;
body width 4.4 mm
4
Functional diagram
2
1
1REXT/CEXT
1CEXT
1Q
6
5
4
1A
1B
1Q
7
3
14
15
1CD
2REXT/CEXT
2CEXT
2Q
10
11
12
2A
2B
2Q
9
13
2CD
001aae727
Figure 1. Functional diagram
74HC4538_Q100
All information provided in this document is subject to legal disclaimers.
© Nexperia B.V. 2017. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2017
2 / 20
Nexperia
Dual retriggerable precision monostable multivibrator
74HC4538-Q100
nB
nA
V
CC
nREXT/CEXT
V
ref1
nCEXT
GND
nCD
enable
power-on reset
V
CC
V
ref2
enable
nQ
nQ
mba338
GND
Figure 2. Logic diagram (one multivibrator)
74HC4538_Q100
All information provided in this document is subject to legal disclaimers.
© Nexperia B.V. 2017. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2017
3 / 20
Nexperia
Dual retriggerable precision monostable multivibrator
74HC4538-Q100
5
Pinning information
5.1 Pinning
74HC4538-Q100
1CEXT
1REXT/CEXT
1CD
1B
1A
1Q
1Q
GND
1
2
3
4
5
6
7
8
aaa-026544
16 V
CC
15 2CEXT
14 2REXT/CEXT
13 2CD
12 2B
11 2A
10 2Q
9
2Q
1CEXT
1REXT/CEXT
1CD
1B
1A
1Q
1Q
GND
1
2
3
4
5
6
7
8
aaa-026546
74HC4538-Q100
16 V
CC
15 2CEXT
14 2REXT/CEXT
13 2CD
12 2B
11 2A
10 2Q
9
2Q
Figure 3. Pin configuration for SO16
Figure 4. Pin configuration for TSSOP16
5.2 Pin description
Table 2. Pin description
Symbol
1CEXT, 2CEXT
1REXT/CEXT, 2REXT/CEXT
1CD, 2CD
1B, 2B
1A, 2A
1Q, 2Q
1Q, 2Q
GND
V
CC
Pin
1, 15
2, 14
3, 13
4, 12
5, 11
6, 10
7, 9
8
16
Description
external capacitor connection (always connected to ground)
external capacitor/resistor connection
direct reset input (active LOW)
input (LOW to HIGH triggered)
input (HIGH to LOW triggered)
output
complementary output (active LOW)
ground (0 V)
supply voltage
74HC4538_Q100
All information provided in this document is subject to legal disclaimers.
© Nexperia B.V. 2017. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2017
4 / 20
Nexperia
Dual retriggerable precision monostable multivibrator
74HC4538-Q100
6
Functional description
[1]
Table 3. Function table
Inputs
nA
↓
H
X
[1]
Outputs
nB
L
↑
X
nCD
H
H
L
nQ
nQ
L
H
H = HIGH voltage level; L = LOW voltage level; X = don’t care;
↑ = positive-going transition; ↓ = negative-going transition;
= one HIGH level output pulse, with the pule width determined by C
EXT
and R
EXT
;
= one LOW level output pulse, with the pulse width determined by C
EXT
and R
EXT
.
(1)
(1)
(2)
(1)
nB input
(3)
nA input
(4)
nCD input
nREXT/CEXT input
V
ref1
V
ref2
V
ref1
V
ref2
nQ output
T
T
T
(5)
001aae737
(1) Positive edge triggering.
(2) Positive edge re-triggering (pulse lengthening).
(3) Negative edge triggering.
(4) Reset (pulse shortening).
(5) T
W
= 0.7 x R
EXT
x C
EXT
(see also
Figure 6.
Figure 5. Timing diagram
CEXT
GND
nCEXT
nA
nB
REXT
V
CC
nREXT/CEXT
nQ
nQ
T
T = 0.7 × R
EXT
× C
EXT
nCD
001aak192
Figure 6. Connection of the external timing components R
EXT
and C
EXT
74HC4538_Q100
All information provided in this document is subject to legal disclaimers.
© Nexperia B.V. 2017. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2017
5 / 20
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