DATA SH EET
Product specification
File under Integrated Circuits, IC06 December 1990
INTEGRATED CIRCUITS
74HC/HCT147
10-to-4 line priority encoder
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
December 1990 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
•ICC category: 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; Tamb = 25 °C; tr= tf= 6 ns
Notes
1. CPD is used to determine the dynamic power dissipation (PDin µW):
PD= CPD ×VCC2×fi+∑(CL×VCC2×fo) where:
fi= input frequency in MHz
fo= output frequency in MHz
∑(CL×VCC2×fo) = sum of outputs
CL= output load capacitance in pF
VCC = supply voltage in V
2. For HC the condition is VI= GND to VCC
For HCT the condition is VI= GND to VCC −1.5 V
ORDERING INFORMATION
See
“74HC/HCT/HCU/HCMOS Logic Package Information”
.
SYMBOL PARAMETER CONDITIONS TYPICAL UNIT
HC HCT
tPHL/ tPLH propagation delay Anto YnCL= 15 pF; VCC = 5 V 15 17 ns
CIinput capacitance 3.5 3.5 pF
CPD power dissipation capacitance per package notes 1 and 2 30 33 pF
December 1990 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 Y0to Y3BCD address outputs (active LOW)
11, 12, 13, 1, 2, 3, 4, 5, 10 A0to A8decimal data inputs (active LOW)
15 n.c. not connected
16 VCC positive supply voltage
Fig.1 Pin configuration. Fig.2 Logic symbol.
Fig.3 IEC logic symbol.
December 1990 4
Philips Semiconductors Product specification
10-to-4 line priority encoder 74HC/HCT147
FUNCTION TABLE
Notes
1. H = HIGH voltage level
L = LOW voltage level
X = don’t care
INPUTS OUTPUTS
A0A1A2A3A4A5A6A7A8Y3Y2Y1Y0
HHHHHHHHHHHHH
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
L
X
X
L
H
X
L
H
H
L
H
H
H
L
L
H
H
H
H
L
L
H
H
L
L
L
H
L
H
X
X
X
X
X
X
X
L
X
X
L
H
X
L
H
H
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
L
H
H
H
H
L
L
L
H
L
H
LHHHHHHHHHHHL
Fig.4 Functional diagram.
December 1990 5
Philips Semiconductors Product specification
10-to-4 line priority encoder 74HC/HCT147
Fig.5 Logic diagram.
December 1990 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
ICC category: MSI
AC CHARACTERISTICS FOR 74HC
GND = 0 V; tr= tf= 6 ns; CL= 50 pF
SYMBOL PARAMETER
Tamb (°C)
UNIT
TEST CONDITIONS
74HC VCC
(V) WAVEFORMS
+25 −40 to +85 −40 to +125
min. typ. max. min. max. min. max.
tPHL/ tPLH propagation delay
Anto Yn
50
18
14
160
32
27
200
40
34
240
48
41 ns 2.0
4.5
6.0 Fig.6
tTHL/ tTLH output transition
time
19
7
6
75
15
6
95
19
16
110
22
19 ns 2.0
4.5
6.0 Fig.6
December 1990 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
ICC category: MSI
Note to HCT types
The value of additional quiescent supply current (∆ICC) for a unit load of 1 is given in the family specifications.
To determine ∆ICC per input, multiply this value by the unit load coefficient shown in the table below.
AC CHARACTERISTICS FOR 74HCT
GND = 0 V; tr= tf= 6 ns; CL= 50 pF
AC WAVEFORMS
PACKAGE OUTLINES
See
“74HC/HCT/HCU/HCMOS Logic Package Outlines”
.
INPUT UNIT LOAD COEFFICIENT
A3, A4, A7, A81.50
A5, A6, A0, A1, A21.10
SYMBOL PARAMETER
Tamb (°C)
UNIT
TEST CONDITIONS
74HCT VCC
(V) WAVEFORMS
+25 −40 to +85 −40 to +125
min. typ. max. min. max. min. max.
tPHL/ tPLH propagation delay
Anto Yn20 35 44 53 ns 4.5 Fig.6
tTHL/ tTLH output transition
time 7 15 19 22 ns 4.5 Fig.6
Fig.6 Waveforms showing the decimal data inputs (An) to output (Yn) propagation delays and the output
transition times.
(1) HC : VM= 50%; VI= GND to VCC.
HCT: VM= 1.3 V; VI= GND to 3 V.
