Semiconductor Components Industries, LLC, 2000
March, 2000 – Rev. 7
1 Publication Order Number:
MC74HC4538A/D
MC74HC4538A
Dual Precision
Monostable Multivibrator
(Retriggerable, Resettable)
The MC74HC4538A is identical in pinout to the MC14538B. The
device inputs are compatible with standard CMOS outputs; with
pullup resistors, they are compatible with LSTTL outputs.
This dual monostable multivibrator may be triggered by either the
positive or the negative edge of an input pulse, and produces a
precision output pulse over a wide range of pulse widths. Because the
device has conditioned trigger inputs, there are no trigger–input rise
and fall time restrictions. The output pulse width is determined by the
external timing components, Rx and Cx. The device has a reset
function which forces the Q output low and the Q
output high,
regardless of the state of the output pulse circuitry.
• Unlimited Rise and Fall Times Allowed on the Trigger Inputs
• Output Pulse is Independent of the Trigger Pulse Width
• ± 10% Guaranteed Pulse Width Variation from Part to Part (Using
the Same Test Jig)
• Output Drive Capability: 10 LSTTL Loads
• Outputs Directly Interface to CMOS, NMOS and TTL
• Operating Voltage Range: 3.0 to 6.0 V
• Low Input Current: 1.0 µA
• High Noise Immunity Characteristic of CMOS Devices
• In Compliance with the Requirements Defined by JEDEC Standard
No. 7A
• Chip Complexity: 145 FETs or 36 Equivalent Gates
LOGIC DIAGRAM
PIN 16 = V
CC
PIN 8 = GND
RX AND CX ARE EXTERNAL COMPONENTS
PIN 1 AND PIN 15 MUST BE HARD WIRED TO GND
CX1R
X
1
V
CC
Q1
RESET 1
B1
A1
TRIGGER
INPUTS
Q1
12
4
5
3
6
7
CX2R
X
2
V
CC
Q2
RESET 2
B2
A2
TRIGGER
INPUTS
Q2
15 14
12
11
13
10
9
SO–16
D SUFFIX
CASE 751B
http://onsemi.com
1
16
PDIP–16
N SUFFIX
CASE 648
1
16
MARKING
DIAGRAMS
1
16
MC74HC4538AN
AWLYYWW
1
16
HC4538A
AWLYWW
A = Assembly Location
WL = Wafer Lot
YY = Year
WW = Work Week
Device Package Shipping
ORDERING INFORMATION
MC74HC4538AN PDIP–16 2000 / Box
MC74HC4538AD SOIC–16
48 / Rail
MC74HC4538ADR2 SOIC–16 2500 / Reel
PIN ASSIGNMENT
13
14
15
16
9
10
11
125
4
3
2
1
8
7
6
A2
RESET 2
CX2/RX2
GND
V
CC
Q2
Q2
B2
A1
RESET 1
CX1/RX1
GND
GND
Q1
Q1
B1
FUNCTION TABLE
Inputs Outputs
Reset A B Q Q
HH
HL
H X L Not Triggered
H H X Not Triggered
H L,H, H Not Triggered
H L L,H, Not Triggered
LX X LH
X X Not Triggered