4-STAGE SYNCHRONOUS
BIDIRECTIONAL COUNTERS
The MC54/74F168 and MC54/74F169 are fully synchronous 4-stage up/
down counters. The F168 is a BCD decade counter; the F169 is a modulo-16
binary counter. Both feature a preset capability for programmable operation,
carry lookahead for easy cascading, and a U/D input to control the direction
of counting. All state changes, whether in counting or parallel loading, are initi-
ated by the LOW-to-HIGH transition of the clock.
•
Asynchronous Counting and Loading
•
Built-In Lookahead Carry Capability
•
Presettable for Programmable Operation
CONNECTION DIAGRAM
(TOP VIEW)
VCC
16
TC
15
Q0
14
Q1
13
Q2
12
Q3
11
CET
10
PE
9
16
MC54/74F168
MC54/74F169
4-STAGE SYNCHRONOUS
BIDIRECTIONAL COUNTERS
FAST™ SCHOTTKY TTL
J SUFFIX
CERAMIC
CASE 620-09
1
16
N SUFFIX
PLASTIC
CASE 648-08
1
1
U/D
2
CP
3
P0
4
P1
5
P2
6
P3
7
CEP
8
GND
MODE SELECT TABLE
PE
L
H
H
H
H
CEP
X
L
L
H
X
CET
X
L
L
X
H
U/D
X
H
L
X
X
Action on Rising
Clock Edge
Load (Pn
Qn)
Count Up (Increment)
Count Down (Decrement)
No Change (Hold)
No Change (Hold)
16
1
D SUFFIX
SOIC
CASE 751B-03
ORDERING INFORMATION
MC54FXXXJ
MC74FXXXN
MC74FXXXD
Ceramic
Plastic
SOIC
H = HIGH Voltage Level; L = LOW Voltage Level; X = Don’t Care
STATE DIAGRAMS
MC54/74F169
0
1
2
3
4
LOGIC SYMBOL
9 3 4 5 6
PE P0 P1 P2 P3
U/D
CEP
TC
CET
CP
Q0 Q1 Q2 Q3
14 13 12 11
MC54/74F168
0
1
2
3
15
5
1
7
10
2
10
9
11
15
4
14
13
14
6
15
13
7
VCC = Pin 16
GND = Pin 8
8
7
6
5
12
12
11
10
9
8
COUNT DOWN
COUNT UP
COUNT DOWN
COUNT UP
FAST AND LS TTL DATA
4-82
MC54/74F168
•
MC54/74F169
FUNCTIONAL DESCRIPTION
The F168 and F169 use edge-triggered J-K type flip-flops
and have no constraints on changing the control or data input
signals in either state of the clock. The only requirement is that
the various inputs attain the desired state at least a setup time
before the rising edge of the clock and remain valid for the rec-
ommended hold time thereafter. The parallel load operation
takes precedence over other operations, as indicated in the
Mode Select Table. When PE is LOW, the data on the P0-P3
inputs enters the flip-flops on the next rising edge of the clock.
In order for counting to occur, both CEP and CET must be
LOW and PE must be HIGH; the U/D input then determines
the direction of counting. The Terminal Count (TC) output is
normally HIGH and goes LOW, provided that CET is LOW,
when a counter reaches zero in the Count Down mode or
reaches 9 (15 for the F169) in the Count Up mode. The TC
GUARANTEED OPERATING RANGES
Symbol
VCC
TA
IOH
IOL
Supply Voltage
Operating Ambient Temperature Range
Output Current — High
Output Current — Low
Parameter
54, 74
54
74
54, 74
54, 74
Min
4.5
–55
0
Typ
5.0
25
25
Max
5.5
125
70
–1.0
20
mA
mA
Unit
V
°C
output state is not a function of the Count Enable Parallel
(CEP) input level. The TC output of the F168 decade counter
can also be LOW in the illegal states 11, 13, and 15, which can
occur when power is turned on or via parallel loading. If an ille-
gal state occurs, the F168 will return to the legitimate se-
quence within two counts. Since the TC signal is derived by
decoding the flip-flop states, there exists the possibility of de-
coding spikes on TC. For this reason the use of TC as a clock
signal is not recommended (see logic equations below).
1) Count Enable = CEP
•
CET
•
PE
2) Up: (′F168): TC = Q0
•
Q1
•
Q2
•
Q3
•
(Up)
•
CET
(′F169): TC = Q0
•
Q1
•
Q2
•
Q3
•
(Up)
•
CET
3) Down: TC = Q0
•
Q1
•
Q2
•
Q3
•
(Down)
•
CET
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE
(unless otherwise specified)
Limits
Symbol
VIH
VIL
VIK
VOH
Parameter
Input HIGH Voltage
Input LOW Voltage
Input Clamp Diode Voltage
Output HIGH Voltage
54, 74
74
VOL
IIH
Output LOW Voltage
Input HIGH Current
2.5
2.7
3.4
3.4
0.35
0.5
20
0.1
Input LOW Current
IIL
IOS
ICC
CET
Other Inputs
Output Short Circuit Current (Note 2)
Power Supply Current
–60
–1.2
–0.6
–150
52
mA
mA
VCC= MAX, VOUT = 0 V
VCC = MAX
mA
VCC = MAX, VIN = 0.5 V
Min
2.0
0.8
–1.2
Typ
Max
Unit
V
V
V
V
V
V
µA
mA
Test Conditions
Guaranteed Input HIGH Voltage for
All Inputs
Guaranteed Input LOW Voltage for
All Inputs
VCC = MIN, IIN = – 18 mA
IOH = – 1.0 mA
IOH = – 1.0 mA
IOL = 20 mA
VCC = 4.50 V
VCC = 4.75 V
VCC = MIN
VCC = MAX, VIN = 2.7 V
VCC = MAX, VIN = 7.0 V
NOTES:
1. For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions for the applicable device type.
2. Not more than one output should be shorted at a time, nor for more than 1 second.
FAST AND LS TTL DATA
4-84
DSP and ARM Processors
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