Page 1
INTEGRATED CIRCUITS
DATA SH EET
For a complete data sheet, please also download:
•The IC06 74HC/HCT/HCU/HCMOS Logic Family Specifications
•The IC06 74HC/HCT/HCU/HCMOS Logic Package Information
•The IC06 74HC/HCT/HCU/HCMOS Logic Package Outlines
74HC/HCT147
10-to-4 line priority encoder
Product specification
File under Integrated Circuits, IC06
December 1990
Page 2
Philips Semiconductors Product specification
10-to-4 line priority encoder 74HC/HCT147
FEATURES
• Encodes 10-line decimal to 4-line BCD
• Useful for 10-position switch encoding
• Used in code converters and generators
• Output capability: standard
• ICCcategory: MSI
GENERAL DESCRIPTION
The 74HC/HCT147 are high-speed Si-gate CMOS devices
and are pin compatible with low power Schottky TTL
(LSTTL). They are specified in compliance with JEDEC
standard no. 7A.
The 74HC/HCT147 9-input priority encoders accept data
from nine active LOW inputs (A0to A8) and provide a
binary representation on the four active LOW outputs
(Y0to Y3). 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 A8having the highest priority.
The devices provide the 10-line to 4-line priority encoding
function by use of the implied decimal “zero”. The “zero” is
encoded when all nine data inputs are HIGH, forcing all
four outputs HIGH.
QUICK REFERENCE DATA
GND = 0 V; T
= 25 °C; tr= tf= 6 ns
amb
SYMBOL PARAMETER CONDITIONS
t
PHL
C
C
I
PD
/ t
PLH
propagation delay Anto Y
n
CL= 15 pF; VCC= 5 V 15 17 ns
input capacitance 3.5 3.5 pF
power dissipation capacitance per package notes 1 and 2 30 33 pF
TYPICAL
UNIT
HC HCT
Notes
1. C
is used to determine the dynamic power dissipation (PDin µW):
PD
PD= CPD× V
2
× fi+∑(CL× V
CC
2
× fo) where:
CC
fi= input frequency in MHz
fo= output frequency in MHz
∑ (CL× V
2
× fo) = sum of outputs
CC
CL= output load capacitance in pF
VCC= supply voltage in V
2. For HC the condition is VI= GND to V
CC
For HCT the condition is VI= GND to VCC− 1.5 V
ORDERING INFORMATION
“74HC/HCT/HCU/HCMOS Logic Package Information”
See
.
December 1990 2
Page 3
Philips Semiconductors Product specification
10-to-4 line priority encoder 74HC/HCT147
PIN DESCRIPTION
PIN NO. SYMBOL NAME AND FUNCTION
8 GND ground (0 V)
9, 7, 6, 14
11, 12, 13, 1, 2, 3, 4, 5, 10
15 n.c. not connected
16 V
Y0to Y3BCD address outputs (active LOW)
A0to A8decimal data inputs (active LOW)
CC
positive supply voltage
Fig.1 Pin configuration. Fig.2 Logic symbol.
Fig.3 IEC logic symbol.
December 1990 3
Page 4
Philips Semiconductors Product specification
10-to-4 line priority encoder 74HC/HCT147
Fig.4 Functional diagram.
FUNCTION TABLE
INPUTS OUTPUTS
A
0
A
1
A
2
A
3
A
4
A
5
A
6
A
7
A
8
Y
3
Y
2
Y
1
Y
0
HHHHHHHHHHHHH
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
L
X
X
X
X
X
X
L
H
X
X
X
X
X
L
H
H
X
X
X
X
L
H
H
H
X
X
X
L
H
H
H
H
X
X
L
H
H
H
H
H
X
L
H
H
H
H
H
H
L
H
H
H
H
H
H
H
L
L
H
H
H
H
H
H
H
H
L
L
L
L
H
H
H
H
L
L
H
H
L
L
L
H
L
H
L
H
L
H
LHHHHHHHHHHHL
Notes
1. H = HIGH voltage level
L = LOW voltage level
X = don’t care
December 1990 4
Page 5
Philips Semiconductors Product specification
10-to-4 line priority encoder 74HC/HCT147
Fig.5 Logic diagram.
December 1990 5
Page 6
Philips Semiconductors Product specification
10-to-4 line priority encoder 74HC/HCT147
DC CHARACTERISTICS FOR 74HC
For the DC characteristics see
“74HC/HCT/HCU/HCMOS Logic Family Specifications”
Output capability: standard
ICCcategory: MSI
AC CHARACTERISTICS FOR 74HC
GND = 0 V; t
= tf= 6 ns; CL= 50 pF
r
SYMBOL PARAMETER
min. typ. max. min. max. min. max.
t
PHL
t
THL
/ t
/ t
propagation delay
PLH
TLH
Anto Y
output transition
time
n
(°C)
T
amb
74HC
+25 −40 to +85 −40 to +125
50
18
14
19
7
6
160
32
27
75
15
6
200
40
34
95
19
16
240
48
41
110
22
19
.
ns
ns
UNIT
TEST CONDITIONS
WAVEFORMS
V
CC
(V)
2.0
4.5
Fig.6
6.0
2.0
4.5
Fig.6
6.0
December 1990 6
Page 7
Philips Semiconductors Product specification
10-to-4 line priority encoder 74HC/HCT147
DC CHARACTERISTICS FOR 74HCT
For the DC characteristics see
“74HC/HCT/HCU/HCMOS Logic Family Specifications”
.
Output capability: standard
ICCcategory: MSI
Note to HCT types
The value of additional quiescent supply current (∆I
) for a unit load of 1 is given in the family specifications.
CC
To determine ∆ICCper input, multiply this value by the unit load coefficient shown in the table below.
INPUT UNIT LOAD COEFFICIENT
A3, A4, A7, A
8
1.50
A5, A6, A0, A1, A21.10
AC CHARACTERISTICS FOR 74HCT
GND = 0 V; t
= tf= 6 ns; CL= 50 pF
r
T
amb
(°C)
TEST CONDITIONS
74HCT
SYMBOL PARAMETER
+25 −40 to +85 −40 to +125
UNIT
V
(V)
min. typ. max. min. max. min. max.
t
PHL
t
THL
/ t
/ t
propagation delay
PLH
Anto Y
output transition
TLH
time
n
20 35 44 53 ns 4.5 Fig.6
7 15 19 22 ns 4.5 Fig.6
WAVEFORMS
CC
AC WAVEFORMS
(1) HC : VM= 50%; VI= GND to VCC.
HCT: V
= 1.3 V; VI= GND to 3 V.
M
Fig.6 Waveforms showing the decimal data inputs (An) to output (Yn) propagation delays and the output
transition times.
PACKAGE OUTLINES
“74HC/HCT/HCU/HCMOS Logic Package Outlines”
See
.
December 1990 7
Loading...