74F161A • 74F163A Synchronous Presettable Binary Counter
April 1988
Revised July 1999
74F161A • 74F163A
Synchronous Presettable Binary Counter
General Description
The 74F161A and 74F163A are high-speed synchronous
modulo-16 binary counters. They are synchronously pre-
settable for application in programmable dividers and have
two types of Count Enable inputs plus a Terminal Count
output for versatility in forming synchronous multi-stage
counters. The 74F161A has an asynchronous Master-
Reset input that overrides all other inputs and forces the
outputs LOW. The 74F163A has a Synchronous Reset
input that overrides counting and parallel loading and
allows the outputs to be simultaneously reset on the rising
edge of the clock. The 74F161A and 74F163A are high-
speed versions of the 74F161 and 74F163.
Features
s
Synchronous counting and loading
s
High-speed synchronous expansion
s
Typical count frequency of 120 MHz
Ordering Code:
Order Number
74F161ASC
74F161ASJ
74F161APC
74F163ASC
74F163ASJ
74F163APC
Package Number
M16A
M16D
N16E
M16A
M16D
N16E
Package Description
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
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 Diagrams
74F161A
74F163A
© 1999 Fairchild Semiconductor Corporation
DS009486
www.fairchildsemi.com
74F161A • 74F163A
Logic Symbols
74F161A
IEEE/IEC
74F163A
IEEE/IEC
74F161A
74F163A
Unit Loading/Fan Out
U.L.
Pin Names
CEP
CET
CP
MR (74F161A)
SR (74F163A)
P
0
–P
3
PE
Q
0
–Q
3
TC
Description
HIGH/LOW
Count Enable Parallel Input
Count Enable Trickle Input
Clock Pulse Input (Active Rising Edge)
Asynchronous Master Reset Input (Active LOW)
Synchronous Reset Input (Active LOW)
Parallel Data Inputs
Parallel Enable Input (Active LOW)
Flip-Flop Outputs
Terminal Count Output
1.0/1.0
1.0/2.0
1.0/1.0
1.0/1.0
1.0/2.0
1.0/1.0
1.0/2.0
50/33.3
50/33.3
Input I
IH
/I
IL
Output I
OH
/I
OL
20
µA/−0.6
mA
20
µA/−1.2
mA
20
µA/−0.6
mA
20
µA/−0.6
mA
20
µA/−1.2
mA
20
µA/−0.6
mA
20
µA/−1.2
mA
−1
mA/20 mA
−1
mA/20 mA
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2
74F161A • 74F163A
Functional Description
The 74F161A and 74F163A count in modulo-16 binary
sequence. From state 15 (HHHH) they increment to state 0
(LLLL). The clock inputs of all flip-flops are driven in paral-
lel through a clock buffer. Thus all changes of the Q outputs
(except due to Master Reset of the 74F161A) occur as a
result of, and synchronous with, the LOW-to-HIGH transi-
tion of the CP input signal. The circuits have four funda-
mental modes of operation, in order of precedence:
asynchronous reset (74F161A), synchronous reset
(74F163A), parallel load, count-up and hold. Five control
inputs—Master Reset (MR, 74F161A), Synchronous Reset
(SR, 74F163A), Parallel Enable (PE), Count Enable Paral-
lel (CEP) and Count Enable Trickle (CET)—determine the
mode of operation, as shown in the Mode Select Table. A
LOW signal on MR overrides all other inputs and asynchro-
nously forces all outputs LOW. A LOW signal on SR over-
rides counting and parallel loading and allows all outputs to
go LOW on the next rising edge of CP. A LOW signal on PE
overrides counting and allows information on the Parallel
Data (P
n
) inputs to be loaded into the flip-flops on the next
rising edge of CP. With PE and MR ('F161A) or SR
(74F163A) HIGH, CEP and CET permit counting when
both are HIGH. Conversely, a LOW signal on either CEP or
CET inhibits counting.
The 74F161A and 74F163A use D-type edge triggered flip-
flops and changing the SR, PE, CEP and CET inputs when
the CP is in either state does not cause errors, provided
that the recommended setup and hold times, with respect
to the rising edge of CP, are observed.
The Terminal Count (TC) output is HIGH when CET is
HIGH and the counter is in state 15. To implement synchro-
nous multi-stage counters, the TC outputs can be used
with the CEP and CET inputs in two different ways. Please
refer to the 74F568 data sheet. The TC output is subject to
decoding spikes due to internal race conditions and is
therefore not recommended for use as a clock or asynchro-
nous reset for flip-flops, counters or registers.
Logic Equations: Count Enable
=
CEP • CET • PE
TC
=
Q
0
• Q
1
• Q
2
• Q
3
• CET
Mode Select Table
SR
(Note 1)
L
H
H
H
H
PE CET
X
L
H
H
H
X
X
H
L
X
CE
P
X
X
H
X
L
Action on the Rising
Clock Edge (
Reset (Clear)
Load (P
n
→Q
n
)
Count (Increment)
No Change (Hold)
No Change (Hold)
)
State Diagram
H
=
HIGH Voltage Level
L
=
LOW Voltage Level
X
=
Immaterial
Note 1:
For 74F163A only
Block Diagram
3
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74F161A • 74F163A
Absolute Maximum Ratings
(Note 2)
Storage Temperature
Ambient Temperature under Bias
Junction Temperature under Bias
V
CC
Pin Potential to Ground Pin
Input Voltage (Note 3)
Input Current (Note 3)
Voltage Applied to Output
in HIGH State (with V
CC
=
0V)
Standard Output
3-STATE Output
Current Applied to Output
in LOW State (Max)
ESD Last Passing Voltage (Min)
twice the rated I
OL
(mA)
4000V
−0.5V
to V
CC
−0.5V
to
+5.5V
−65°C
to
+150°C
−55°C
to
+125°C
−55°C
to
+150°C
−0.5V
to
+7.0V
−0.5V
to
+7.0V
−30
mA to
+5.0
mA
Recommended Operating
Conditions
Free Air Ambient Temperature
Supply Voltage
0°C to
+70°C
+4.5V
to
+5.5V
Note 2:
Absolute maximum ratings are values beyond which the device
may be damaged or have its useful life impaired. Functional operation
under these conditions is not implied.
Note 3:
Either voltage limit or current limit is sufficient to protect inputs.
DC Electrical Characteristics
Symbol
V
IH
V
IL
V
CD
V
OH
V
OL
I
IH
I
BVI
I
CEX
V
ID
I
OD
I
IL
I
OS
I
CC
Parameter
Input HIGH Voltage
Input LOW Voltage
Input Clamp Diode Voltage
Output HIGH
Voltage
Output LOW
Voltage
Input HIGH
Current
Input HIGH Current
Breakdown Test
Output HIGH
Leakage Current
Input Leakage
Test
Output Leakage
Circuit Current
Input LOW Current
−60
37
4.75
3.75
−0.6
−1.2
Output Short-Circuit Current
Power Supply Current
−150
55
10% V
CC
5% V
CC
10% V
CC
2.5
2.7
0.5
5.0
7.0
50
Min
2.0
0.8
−1.2
Typ
Max
Units
V
V
V
V
V
µA
µA
µA
V
µA
mA
mA
mA
mA
Min
Min
Min
Max
Max
Max
0.0
0.0
Max
Max
Max
Max
I
OL
=
20 mA
V
IN
=
2.7V
V
IN
=
7.0V
V
OUT
=
V
CC
I
ID
=
1.9
µA
All Other Pins Grounded
V
IOD
=
150 mV
All Other Pins Grounded
V
IN
=
0.5V (CEP, CP, MR, P
0
–P
3
)
V
IN
=
0.5V (CET, PE, SR)
V
OUT
=
0V
V
CC
Conditions
Recognized as a HIGH Signal
Recognized as a LOW Signal
I
IN
= −18
mA
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4
74F161A • 74F163A
AC Electrical Characteristics
T
A
= +25°C
Symbol
Parameter
Min
f
MAX
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PHL
t
PHL
Maximum Count Frequency
Propagation Delay
CP to Q
n
(PE Input HIGH)
Propagation Delay
CP to Q
n
(PE Input LOW)
Propagation Delay
CP to TC
Propagation Delay
CET to TC
Propagation Delay
MR to Q
n
(74F161A)
Propagation Delay
MR to TC (74F161A)
4.5
8.0
10.5
4.5
12.5
4.5
11.5
ns
100
3.5
3.5
4.0
4.0
5.0
5.0
2.5
2.5
5.5
V
CC
= +5.0V
C
L
=
50 pF
Typ
120
5.5
7.5
6.0
6.0
10.0
10.0
4.5
4.5
9.0
7.5
10.0
8.5
8.5
14.0
14.0
7.5
7.5
12.0
Max
T
A
= −55°C
to
+125°C
V
CC
= +5.0V
C
L
=
50 pF
Min
75
3.5
3.5
4.0
4.0
5.0
5.0
2.5
2.5
5.5
9.0
11.5
10.0
10.0
16.5
15.5
9.0
9.0
14.0
Max
T
A
=
0°C to
+70°C
V
CC
= +5.0V
C
L
=
50 pF
Min
90
3.5
3.5
4.0
4.0
5.0
5.0
2.5
2.5
5.5
8.5
11.0
9.5
9.5
15.0
15.0
8.5
8.5
13.0
ns
ns
ns
ns
Max
MHz
Units
AC Operating Requirements
T
A
= +25°C
Symbol
Parameter
V
CC
= +5.0V
Min
t
S
(H)
t
S
(L)
t
H
(H)
t
H
(L)
t
S
(H)
t
S
(L)
t
H
(H)
t
H
(L)
t
S
(H)
t
S
(L)
t
H
(H)
t
H
(L)
t
W
(H)
t
W
(L)
t
W
(H)
t
W
(L)
t
W
(L)
t
REC
Setup Time, HIGH or LOW
P
n
to CP
Hold Time, HIGH or LOW
P
n
to CP
Setup Time, HIGH or LOW
PE or SR to CP
Hold Time, HIGH or LOW
PE or SR to CP
Setup Time, HIGH or LOW
CEP or CET to CP
Hold Time, HIGH or LOW
CEP or CET to CP
Clock Pulse Width (Load)
HIGH or LOW
Clock Pulse Width (Count)
HIGH or LOW
MR Pulse Width, LOW
(74F161A)
Recovery Time
MR to CP (74F161A)
6.0
6.0
6.0
ns
5.0
5.0
2.0
2.0
11.0
8.5
2.0
0
11.0
5.0
0
0
5.0
5.0
4.0
6.0
5.0
Max
T
A
= −55°C
to
+125°C
V
CC
= +5.0V
Min
5.5
5.5
2.5
2.5
13.5
10.5
3.6
0
13.0
6.0
0
0
5.0
5.0
5.0
8.0
5.0
Max
T
A
=
0°C to
+70°C
V
CC
= +5.0V
Min
5.0
5.0
2.0
2.0
11.5
9.5
2.0
0
11.5
5.0
0
0
5.0
5.0
4.0
7.0
5.0
ns
ns
ns
ns
ns
ns
Max
Units
5
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