Integral IN74LS161 Synchronous 4 bit counters; binary, direct reset Datasheet

TECHNICAL DATA
IN74LS161
Synchronous 4 Bit Counters; Binary,
Direct Reset
This synchronous, presettable counter features an internal carry lookahead for application in high-speed counting designs. Synchronous
operation is provided by having all flip-flops clocked simultaneously so
that the outputs change conicident with each other when so instructed by
the count-enable inputs and internal gating.
This mode of operation eliminates the output counting spikes that are
normally associated with asynchronous (ripple clock) counters. A buffered
clock input triggers the four flip-flops on the rising (positive-going) edge
of the clock input wave form.
This counter is fully programmable; that is the outputs may be preset
to either level. As presetting is synchronous setting up a low level at the
load input disables the counter and causes the outputs to agree with the
setup data after the next clock pulse regardless of the levels of the enable
inputs.
The carry look-ahead circuitry provides for cascading counters for nbit synchronous applications without additional gating. Instrumental in
accomplishiing this function are two counter-enable inputs and a ripple
carry output. Both countenable inputs (ENABLE P and ENABLE T)
must be high to count, and ENABLE T is fed forward to enable the
ripple carry output. The ripple carry output thus enabled will produce a
high-level output pulse with a duration approximately equal to the high
level portion of the QA output. The high-level overflow ripple carry
pulse can be enable successive cascaded stages. Transitions at the
ENPor ENT are allowed regardless of the level of the clock input.
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ORDERING INFORMATION
IN74LS161N Plastic
IN74LS161D SOIC
TA = 0° to 70° C for all packages
PIN ASSIGNMENT
Internal Look-Ahead for Fast Counting
Carry Output for n-Bit Cascading
Synchronous Counting
Synchronously Programmable
Load Control Line
Diode-Clamped Inputs
LOGIC DIAGRAM
PIN 16 =VCC
PIN 8 = GND
1
IN74LS161
FUNCTION TABLE
Inputs
Outputs
Reset
Load
Enable
P
Enable
T
Clock
Q0
Q1
Q2
Q3
Function
L
X
X
X
X
L
L
L
L
Reset to “0”
H
L
X
X
P0
P1
P2
P3
Preset Data
H
H
X
L
No change
No count
H
H
L
X
No change
No count
H
H
H
H
Count up
Count
H
X
X
X
No change
No count
X=don’t care
P0,P1,P2,P3 = logic level of Data inputs
Ripple Carry Out = Enable T • Q0 • Q1 • Q2 • Q3
MAXIMUM RATINGS*
Symbol
Parameter
Value
Unit
VCC
Supply Voltage
7.0
V
VIN
Input Voltage
7.0
V
VOUT
Output Voltage
5.5
V
Tstg
Storage Temperature Range
-65 to +150
°C
*
Maximum Ratings are those values beyond which damage to the device may occur.
Functional operation should be restricted to the Recommended Operating Conditions.
RECOMMENDED OPERATING CONDITIONS
Symbol
Parameter
Min
Max
Unit
5.25
V
VCC
Supply Voltage
4.75
VIH
High Level Input Voltage
2.0
VIL
Low Level Input Voltage
0.8
V
IOH
High Level Output Current
-0.4
mA
IOL
Low Level Output Current
8.0
mA
fclock
Clock frequency
0
25
MHz
tw(clock)
Width of clock pulse
25
ns
tw(reset)
Width of reset pulse
20
ns
tsu
Setup time
Data inputs P0, P1, P2, P3
20
Enable P or T
20
Load
20
th
Hold time at any input
3
TA
Ambient Temperature Range
0
V
ns
ns
+70
°C
2
IN74LS161
DC ELECTRICAL CHARACTERISTICS over full operating conditions
Guaranteed Limit
Symbol
Parameter
Test Conditions
Min
Max
Unit
-1.5
V
VIK
Input Clamp Voltage
VCC = min, IIN = -18 mA
VOH
High Level Output Voltage
VCC = min, IOH = -0.4 mA
VOL
Low Level Output Voltage
VCC = min, IOL = 4 mA
0.4
VCC = min, IOL = 8 mA
0.5
VCC = max
Data or enable P
20
VIN =2.7 V
Load, clock or
enable T
40
Reset
20
VCC = max
Data or enable P
0.1
VIN =7.0 V
Load, clock or
enable T
0.2
Reset
0.1
VCC = max
Data or enable P
-0.4
VIN =0.4 V
Load, clock or
enable T
Reset
-0.8
IIH
IIL
High Level Input Current
Low Level Input Current
IO
Output Short Circuit Current
VCC = max, VO = 0 V
(Note 1)
ICC
Supply
Current
All outputs high
All outputs low
2.7
-20
V
V
µA
mA
mA
-100
mA
VCC = max (Note 2)
31
mA
VCC = max (Note 3)
32
Note 1: Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 2: ICCH is measured with the load high, then again with the load low, with all other inputs high and all outputs
open.
Note 3: ICCL is measured with the clock input high, then again with the clock input low, with all other inputs low and all
outputs open.
3
IN74LS161
AC ELECTRICAL CHARACTERISTICS (TA=25°C, VCC = 5.0 V, CL = 15 pF, RL = 2 kΩ, tr =15
ns, tf = 6.0 ns)
Symbol
Parameter
Min
Max
Unit
tPLH
Propagation Delay, Clock to Ripple carry
35
ns
tPHL
Propagation Delay, Clock to Ripple carry
35
ns
tPLH
Propagation Delay, Clock (load input high) to Any Q
24
ns
tPHL
Propagation Delay, Clock (load input high) to Any Q
27
ns
tPLH
Propagation Delay, Clock (load input low) to Any Q
24
ns
tPHL
Propagation Delay, Clock (load input low) to Any Q
27
ns
tPLH
Propagation Delay, Enable T to Ripple carry
14
ns
tPHL
Propagation Delay, Enable T to Ripple carry
14
ns
tPHL
Propagation Delay, Reset to Any Q
28
ns
Figure 1. Switching Waveform
Figure 2. Switching Waveform
Figure 3. Switching Waveform
Figure 4. Switching Waveform
4
IN74LS161
NOTES A. CL includes probe and jig capacitance.
B. All diodes are 1N916 or 1N3064.
Figure 5. Test Circuit
Sequence illustrated in waveforms:
1. Reset outputs to zero.
2. Preset to binary twelve.
3. Count to thirteen, fourteen, fifteen, zero, one, and two.
4. Inhibit.
Figure 7. Timing Diagram
5
IN74LS161
N SUFFIX PLASTIC DIP
(MS - 001BB)
A
Dimension, mm
9
16
Symbol
MIN
MAX
A
18.67
19.69
B
6.1
7.11
B
1
8
5.33
C
F
L
C
D
0.36
0.56
F
1.14
1.78
G
2.54
H
7.62
-T- SEATING
PLANE
N
G
K
M
H
D
J
0.25 (0.010) M T
NOTES:
1. Dimensions “A”, “B” do not include mold flash or protrusions.
Maximum mold flash or protrusions 0.25 mm (0.010) per side.
J
0°
10°
K
2.92
3.81
L
7.62
8.26
M
0.2
0.36
N
0.38
D SUFFIX SOIC
(MS - 012AC)
Dimension, mm
A
16
9
H
B
1
G
P
8
R x 45
C
-TK
D
SEATING
PLANE
J
0.25 (0.010) M T C M
NOTES:
1. Dimensions A and B do not include mold flash or protrusion.
2. Maximum mold flash or protrusion 0.15 mm (0.006) per side
for A; for B ‑ 0.25 mm (0.010) per side.
F
M
Symbol
MIN
MAX
A
9.8
10
B
3.8
4
C
1.35
1.75
D
0.33
0.51
F
0.4
1.27
G
1.27
H
5.72
J
0°
8°
K
0.1
0.25
M
0.19
0.25
P
5.8
6.2
R
0.25
0.5
6
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