MOTOROLA MC54FXXXJ 8-line to 3-line priority encoder fast shottky ttl Datasheet

MC54/74F148
8-LINE TO 3-LINE
PRIORITY ENCODER
The MC54/74F148 provides three bits of binary coded output representing
the position of the highest order active input, along with an output indicating
the presence of any active input. It is easily expanded via input and output enables to provide priority encoding over many bits.
• Encodes Eight Data Lines in Priority
• Provides 3-Bit Binary Priority Code
• Input Enable Capability
• Signals When Data Present on Any Input
• Cascadable for Priority Encoding of n Bits
8-LINE TO 3-LINE
PRIORITY ENCODER
FAST SHOTTKY TTL
J SUFFIX
CERAMIC
CASE 620-09
CONNECTION DIAGRAM DIP (TOP VIEW)
VCC
EO
GS
I3
I2
I1
I0
A0
16
15
14
13
12
11
10
9
16
1
N SUFFIX
PLASTIC
CASE 648-08
16
1
2
3
4
5
6
7
8
I4
I5
I6
I7
E1
A2
A1
GND
1
D SUFFIX
SOIC
CASE 751B-03
LOGIC DIAGRAM
16
(10)
I0
I1
I2
I3
1
(15)
(11)
(14)
EO
GS
ORDERING INFORMATION
MC54FXXXJ
MC74FXXXN
MC74FXXXD
(12)
(9)
Ceramic
Plastic
SOIC
A0
(13)
LOGIC SYMBOL
I4
(1)
10 11 12 13 1
(7)
I5
I6
I7
(2)
3
4 5
I0 I1 I2 I3 I4 I5 I6 I7 E1
(3)
(4)
2
A1
EO
A0
A1
A2
GS
15
9
7
6
14
(6)
A2
(5)
E1
NOTE:
This diagram is provided only for the understanding of logic operations and should not
be used to estimate propagation delays.
FAST AND LS TTL DATA
4-59
VCC = PIN 16
GND = PIN 8
MC54/74F148
GUARANTEED OPERATING RANGES
Symbol
Parameter
VCC
Supply Voltage
TA
Operating Ambient Temperature Range
Min
Typ
Max
Unit
54, 74
4.5
5.0
5.5
V
54
–55
25
125
°C
74
0
25
70
IOH
Output Current — High
54, 74
–1.0
mA
IOL
Output Current — Low
54, 74
20
mA
FUNCTIONAL DESCRIPTION
The F148 8-input priority encoder accepts data from eight
active LOW inputs (I 0–I7) and provides a binary representation on the three active LOW outputs. A priority is assigned to
each input so that when two or more inputs are simultaneously
active, the input with the highest priority is represented on the
output, with input line 7 having the highest priority. A HIGH on
the Enable Input (E1) will force all outputs to the inactive
(HIGH) state and allow new data to settle without producing
erroneous information at the outputs. A Group Signal output
(GS) and Enable Output (EO) are provided along with the
three priority data outputs (A2, A1, A0). GS is active LOW when
any input is LOW; this indicates when any input is active. EO
is active LOW when all inputs are HIGH. Using the Enable
Output along with the Enable Input allows cascading for priority encoding on any number of input signals. Both EO and GS
are in the inactive HIGH state when the Enable Input is HIGH.
FUNCTION TABLE
Inputs
E1
I0
I1
I2
I3
Outputs
I4
I5
I6
I7
GS
A0
A1
A2
EO
H
H
X
X
X
X
X
X
X
X
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
H
L
L
X
X
X
X
X
X
X
L
L
L
L
L
H
L
X
X
X
X
X
X
L
H
L
H
L
L
H
L
X
X
X
X
X
L
H
H
L
L
H
L
H
L
X
X
X
X
L
H
H
H
L
H
H
L
H
L
X
X
X
L
H
H
H
H
L
L
L
H
H
L
X
X
L
H
H
H
H
H
L
H
L
H
H
L
X
L
H
H
H
H
H
H
L
L
H
H
H
L
L
H
H
H
H
H
H
H
L
H
H
H
H
H = HIGH Voltage Level; L = LOW Voltage Level; X = Don’t Care
MSB
LSB
0
1 2 3 4 5 6 7 E1
0
1 2 3 4 5 6 7 E1
’F148
A0
A1
A0
ENABLE
’F148
A2
A1
GS
A2
EO
A0
A1
A3
A2
GS
FLAG
Figure 1. Application: 16-Input Priority Encoder
FAST AND LS TTL DATA
4-60
MC54/74F148
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol
Parameter
VIH
Input HIGH Voltage
VIL
Input LOW Voltage
VIK
Input Clamp Diode Voltage
VOH
Output HIGH Voltage
Typ
Max
2.0
Unit
Test Conditions
V
Guaranteed Input HIGH Voltage
0.8
V
Guaranteed Input LOW Voltage
–1.2
V
IIN = –18 mA
VCC = MIN
54, 74
2.5
3.4
V
IOH = –1.0 mA
VCC = 4.50 V
74
2.7
3.4
V
IOH = –1.0 mA
VCC = 4.75 V
0.5
V
IOL = 20 mA
VCC = MIN
20
µA
VCC = MAX, VIN = 2.7 V
100
µA
VCC = MAX, VIN = 7.0 V
I0, E1
–0.6
mA
I1–I7
–1.2
mA
–150
mA
VCC = MAX, VOUT = 0 V
35
mA
VCC = MAX, VIN = 4.5 V
VOL
Output LOW Voltage
IIH
Input HIGH Current
IIL
Min
IOS
Output Short Circuit Current (Note 2)
ICC
Power Supply Current
0.35
-60
23
VCC = MAX, VIN = 0.5 V
NOTES:
1. For conditions shown as MIN or MAX, use the appropriate value specified under guaranteed operating ranges.
2. Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS
Symbol
Parameter
54/74F
54F
74F
TA = +25°C
VCC = +5.0 V
CL = 50 pF
TA = –55°C to +125°C
VCC = 5.0 V ± 10%
CL = 50 pF
TA = 0°C to 70°C
VCC = 5.0 V ± 10%
CL = 50 pF
Min
Typ
Max
Min
Max
Min
Max
tPLH
Propagation Delay
3.5
7.0
9.0
3.5
11
3.5
10
tPHL
In to An
4.0
8.0
10.5
4.0
13
4.0
12
tPLH
Propagation Delay
2.5
5.0
6.5
2.5
8.5
2.5
7.5
tPHL
In to EO
2.0
5.5
7.5
2.0
9.5
2.0
8.5
tPLH
Propagation Delay
3.0
7.0
9.0
3.0
11
3.0
10
tPHL
In to GS
2.0
6.0
8.0
2.0
10
2.0
9.0
tPLH
Propagation Delay
3.5
6.5
8.5
3.5
10.5
3.5
9.5
tPHL
E1 to An
3.0
6.0
8.0
3.0
10
3.0
9.0
tPLH
Propagation Delay
2.5
5.0
7.0
2.5
9.0
2.5
8.0
tPHL
E1 to GS
3.0
6.0
7.5
3.0
10
3.0
8.5
tPLH
Propagation Delay
3.0
5.5
7.0
3.0
9.0
3.0
8.0
tPHL
E1 to EO
4.5
8.0
10.5
4.5
13
4.5
12
Unit
ns
ns
ns
ns
ns
ns
FAST AND LS TTL DATA
4-61
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