DM74LS390 Dual 4-Bit Decade Counter
August 1986
Revised March 2000
DM74LS390
Dual 4-Bit Decade Counter
General Description
Each of these monolithic circuits contains eight master-
slave flip-flops and additional gating to implement two indi-
vidual four-bit counters in a single package. The
DM74LS390 incorporates dual divide-by-two and divide-
by-five counters, which can be used to implement cycle
lengths equal to any whole and/or cumulative multiples of 2
and/or 5 up to divide-by-100. When connected as a bi-qui-
nary counter, the separate divide-by-two circuit can be
used to provide symmetry (a square wave) at the final out-
put stage. The DM74LS390 has parallel outputs from each
counter stage so that any submultiple of the input count fre-
quency is available for system-timing signals.
Features
s
Dual version of the popular DM74LS90
s
DM74LS390...individual clocks for A and B flip-flops
provide dual
÷
2 and
÷
5 counters
s
Direct clear for each 4-bit counter
s
Dual 4-bit version can significantly improve system den-
sities by reducing counter package count by 50%
s
Typical maximum count frequency...35 MHz
s
Buffered outputs reduce possibility of collector commu-
tation
Ordering Code:
Order Number
DM74LS390M
DM74LS390N
Package Number
M16A
N16E
Package Description
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
© 2000 Fairchild Semiconductor Corporation
DS006433
www.fairchildsemi.com
DM74LS390
Absolute Maximum Ratings
(Note 3)
Supply Voltage
Input Voltage
Clear
A or B
Operating Free Air Temperature Range
Storage Temperature Range
7V
5.5V
0°C to
+70°C
−65°C
to
+150°C
7V
Note 3:
The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Recommended Operating Conditions
Symbol
V
CC
V
IH
V
IL
I
OH
I
OL
f
CLK
f
CLK
t
W
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Clock Frequency (Note 4)
Clock Frequency (Note 5)
Pulse Width (Note 4)
A to Q
A
B to Q
B
A to Q
A
B to Q
B
A
B
Clear HIGH
t
REL
T
A
Clear Release Time (Note 6)(Note 7)
Free Air Operating Temperature
0
0
0
0
20
25
20
25↓
0
70
ns
°C
ns
Parameter
Min
4.75
2
0.8
−0.4
8
25
20
20
15
Nom
5
Max
5.25
Units
V
V
V
mA
mA
MHz
MHz
Note 4:
C
L
=
15 pF, R
L
=
2 kΩ, T
A
=
25°C and V
CC
=
5V.
Note 5:
C
L
=
50 pF, R
L
=
2 kΩ, T
A
=
25°C and V
CC
=
5V.
Note 6:
The symbol (↓) indicates the falling edge of the clear pulse is used for reference.
Note 7:
T
A
=
25°C and V
CC
=
5V.
Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
V
I
V
OH
V
OL
Parameter
Input Clamp Voltage
HIGH Level
Output Voltage
LOW Level
Output Voltage
I
I
Input Current @ Max
Input Voltage
I
IH
HIGH Level
Input Current
I
IL
LOW Level
Input Current
I
OS
I
CC
Short Circuit Output Current
Supply Current
V
CC
=
Max (Note 9)
V
CC
=
Max (Note 10)
Conditions
V
CC
=
Min, I
I
= −18
mA
V
CC
=
Min, I
OH
=
Max
V
IL
=
Max, V
IH
=
Min
V
CC
=
Min, I
OL
=
Max
V
IL
=
Max, V
IH
=
Min
I
OL
=
4 mA, V
CC
=
Min
V
CC
=
Max, V
I
=
7V
V
CC
=
Max
V
I
=
5.5V
V
CC
=
Max
V
I
=
2.7V
V
CC
=
Max, V
I
=
0.4V
Clear
A
B
Clear
A
B
Clear
A
B
−20
15
2.7
3.4
0.35
0.25
0.5
0.4
0.1
0.2
0.4
20
40
80
−0.4
−1.6
−2.4
−100
26
mA
mA
mA
µA
mA
Min
Typ
(Note 8)
Max
−1.5
Units
V
V
V
Note 8:
All typicals are at V
CC
=
5V, T
A
=
25°C.
Note 9:
Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 10:
I
CC
is measured with all outputs OPEN, both CLEAR inputs grounded following momentary connection to 4.5 and all other inputs grounded.
3
www.fairchildsemi.com
Talking
京公网安备 11010802033920号
EEWORLD
