Data sheet acquired from Harris Semiconductor
SCHS123
June 1998
CD54HC4538, CD74HC4538,
CD74HCT4538
High Speed CMOS Logic Dual Retriggerable
Precision Monostable Multivibrator
[ /Title
(CD54
HC453
8,
CD74
HC453
8,
CD74
HCT45
38)
Subect
(High
Speed
CMOS
Logic
Features
• Retriggerable/Resettable Capability
• Trigger and Reset Propagation Delays Independent of
R
, C
X
X
• Triggering from the Leading or Trailing Edge
• Q and
Q Buffered Outputs Available
• Separate Resets
• Wide Range of Output-Pulse Widths
• Schmitt Trigger Input on A and
• Retrigger Time is Independent of C
B Inputs
X
• Fanout (Over Temperature Range)
- Standard Outputs. . . . . . . . . . . . . . . 10 LSTTL Loads
- Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads
• Wide Operating Temperature Range . . . -55
o
C to 125oC
• Balanced Propagation Delay and Transition Times
• Significant Power Reduction Compared to LSTTL
Logic ICs
• HC Types
- 2V to 6V Operation
- High Noise Immunity: N
= 30%, NIH = 30% of V
IL
CC
at VCC = 5V
• HCT Types
- 4.5V to 5.5V Operation
- Direct LSTTL Input Logic Compatibility,
V
= 0.8V (Max), VIH = 2V (Min)
IL
- CMOS Input Compatibility, I
≤ 1µA at VOL, V
l
OH
Pinout
CD54HC4538, CD74HC4538, CD74HCT4538
(PDIP, SOIC, CERDIP)
TOP VIEW
16
1C
1RXC
GND
1R
1A
1B
1Q
1Q
1
X
2
X
3
4
5
6
7
8
V
CC
15
2C
X
14
2RXC
X
13
2R
2A
12
11
2B
2Q
10
9
2Q
Description
The Harris CD54HC4538, CD74HC4538 and
CD74HCT4538 are dual retriggerable/resettable monostable
precision multivibrators for fixed voltage timing applications.
An external resistor (R
) and an external capacitor (CX)
X
control the timing and the accuracy for the circuit.
Adjustment of R
pulse widths from the Q and
and CXprovides a wide range of output
X
Q terminals. The propagation
delay from trigger input-to-output transition and the
propagation delay from reset input-to-output transition are
independent of R
Leading-edge triggering (A) and trailing edge triggering (
and CX.
X
B)
inputs are provided for triggering from either edge of the
input pulse. An unused “A” input should be tied to GND and
an unused
B should be tied to VCC. On power up the IC is
reset. Unused resets and sections must be terminated. In
normal operation the circuit retriggers on the application of
each new trigger pulse. To operate in the non-triggerable
mode
Q is connected to B when leading edge triggering (A)
is used or Q is connected to A when trailing edge triggering
(
B) is used. The period (τ) can be calculated from τ = (0.7)
R
, CX; R
X
is 5kΩ. C
MIN
MIN
is 0pF.
Ordering Information
TEMP. RANGE
PART NUMBER
CD54HC4538F -55 to 125 16 Ld CERDIP F16.3
CD74HC4538E -55 to 125 16 Ld PDIP E16.3
CD74HCT4538E -55 to 125 16 Ld PDIP E16.3
CD74HC4538M -55 to 125 16 Ld SOIC M16.15
CD74HCT4538M -55 to 125 16 Ld SOIC M16.15
NOTES:
1. When ordering, use the entire partnumber. Add the suffix 96 to
obtain the variant in the tape and reel.
2. Wafer anddie for thispart number isavailable which meets all
electrical specifications. Please contactyour local sales office or
Harris customer service for ordering information.
(oC) PACKAGE
PKG.
NO.
CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures.
Copyright
© Harris Corporation 1998
1
File Number 1671.2
CD54HC4538, CD74HC4538, CD74HCT4538
Functional Diagram
4
1A
5
1B
3
1R
13
2R
12
2A
11
2B
GND = 8
= 16
V
CC
TRUTH TABLE
INPUTS OUTPUTS
RABQQ
1Cx 1Rx
12
1Cx 1RxCx
MONO 1
MONO 2
2Cx 2RxCx
15 14
2Cx 2Rx
CL
V
CC
6
1Q
7
1Q
10
2Q
9
2Q
V
CC
R2
R1
CL
Q
LXXLH
XHXLH
XXLLH
HL↓
H↑H
NOTE: H = High Level, L = Low Level, ↑ = Transition from Low to
High, ↓ = Transitionfrom High to Low, One High Level Pulse,
One Low Level Pulse, X = Irrelevant.
p
CL
n
CL
p
n
CL
Q
R1
D
CL
p
n
CL
FIGURE 1. FF DETAIL
2
CD54HC4538, CD74HC4538, CD74HCT4538
16
V
CC
V
CC
COMP II
R1
+
-
R2
V
CC
Q
Q
6(10)
Q
7(9)
Q
2(14)
V
CC
V
CC
HIGH Z
V
CC
D
CL
R2R1
FF
CL
V
CC
R
X
C
1(15)
X
8
3(13)
R
4(12)
A
5(11)
B
FIGURE 2. LOGIC DIAGRAM (1 MONO)
FUNCTIONAL TERMINAL CONNECTIONS
FUNCTION
Leading-Edge
VCC TO
TERMINAL NUMBER
MONO
MONO
1
2
3, 5 11, 13 4 12
GND TO
TERMINAL NUMBER
MONO
MONO
1
INPUT PULSE TO
TERMINAL NUMBER
MONO
2
1
MONO
OTHER
CONNECTIONS
MONO
2
MONO
1
Trigger/Retriggerable
Leading-Edge
3 13 4 12 5-7 11-9
Trigger/Non-Retriggerable
Trailing-Edge
313412511
Trigger/Retriggerable
Trailing-Edge
3 13 5 11 4-6 12-10
Trigger/Non-Retriggerable
NOTES:
3. A retriggerable one-shot multivibrator has anoutput pulse width which is extended one full time period (T)after application of the last
trigger pulse.
4. A non-triggerable one-shot multivibrator has a time period (T) referenced from the application of the first trigger pulse.
T
FIGURE 3. INPUT PULSE TRAIN FIGURE 4. RETRIGGERABLE MODE
PULSE WIDTH (A MODE)
FIGURE5. NON-RETRIGGERABLEMODE
T
PULSE WIDTH
(A MODE)
2
3
CD54HC4538, CD74HC4538, CD74HCT4538
Absolute Maximum Ratings Thermal Information
DC Supply Voltage, VCC. . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 7V
DC Input Diode Current, I
For VI < -0.5V or VI > VCC + 0.5V. . . . . . . . . . . . . . . . . . . . . .±20mA
DC Output Diode Current, I
For VO < -0.5V or VO > VCC + 0.5V . . . . . . . . . . . . . . . . . . . .±20mA
DC Output Source or Sink Current per Output Pin, I
For VO > -0.5V or VO < VCC + 0.5V . . . . . . . . . . . . . . . . . . . .±25mA
DC VCC or Ground Current, ICC . . . . . . . . . . . . . . . . . . . . . . . . .±50mA
IK
OK
O
Operating Conditions
Temperature Range, TA . . . . . . . . . . . . . . . . . . . . . . -55oC to 125oC
Supply Voltage Range, VCC (Note 5)
HC Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2V to 6V
HCT Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.5V to 5.5V
DC Input or Output Voltage, VI, VO . . . . . . . . . . . . . . . . . 0V to V
Input Rise and Fall Times, tr, t
Reset Input:
2V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000ns (Max)
4.5V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500ns (Max)
6V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400ns (Max)
Trigger Inputs A or B:
2V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Unlimited (Max)
4.5V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Unlimited (Max)
6V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Unlimited (Max)
External Timing Resistor, RX (Note 6) . . . . . . . . . . . . . . . .5kΩ (Min)
External Timing Capacitor, CX (Note 6) . . . . . . . . . . . . . . . . .0 (Min)
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation
of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTES:
5. Unless otherwise specified, all voltages are referenced to ground.
6. The maximumallowable values of RXand CXare afunction of leakage of capacitor CX, theleakage of the HC4538, and leakage due to
board layout and surface resistance. Values of RXand CXshould be chosen so that the maximum current into pin 2 or pin 14 is 30mA.
Susceptibility to externally induced noise signals may occur for RX > 1MΩ.
7. θJA is measured with the component mounted on an evaluation PC board in free air.
f
Thermal Resistance (Typical, Note 7) θJA (oC/W) θJC (oC/W)
PDIP Package. . . . . . . . . . . . . . . . . . . 90 N/A
SOIC Package. . . . . . . . . . . . . . . . . . . 160 N/A
CERDIP Package . . . . . . . . . . . . . . . . 130 55
Maximum Junction Temperature. . . . . . . . . . . . . . . . . . . . . . .150oC
Maximum Storage Temperature Range . . . . . . . . . .-65oC to 150oC
Maximum Lead Temperature (Soldering 10s). . . . . . . . . . . . .300oC
(SOIC - Lead Tips Only)
CC
DC Electrical Specifications
PARAMETER SYMBOL
HC TYPES
High Level Input
Voltage
Low Level Input
Voltage
High Level Output
Voltage
CMOS Loads
High Level Output
Voltage
TTL Loads
V
IH
V
IL
V
OH
TEST
CONDITIONS
(V) IO(mA) MIN TYP MAX MIN MAX MIN MAX
I
- - 2 1.5 - - 1.5 - 1.5 - V
- - 2 - - 0.5 - 0.5 - 0.5 V
VIHor VIL-0.02 2 1.9 - - 1.9 - 1.9 - V
-0.02 4.5 4.4 - - 4.4 - 4.4 - V
-0.02 6 5.9 - - 5.9 - 5.9 - V
-4 4.5 3.98 - - 3.84 - 3.7 - V
-5.2 6 5.48 - - 5.34 - 5.2 - V
V
CC
(V)
4.5 3.15 - - 3.15 - 3.15 - V
6 4.2 - - 4.2 - 4.2 - V
4.5 - - 1.35 - 1.35 - 1.35 V
6 - - 1.8 - 1.8 - 1.8 V
- - ---- - - - V
o
C -40oC TO 85oC -55oCTO125oC
25
UNITSV
4