HD74HC147 Datasheet, PDF (1/8 Pages) Hitachi Semiconductor – 10-to-4-line Priority Encoder

HD74HC147
10-to-4-line Priority Encoder
Description
The HD74HC147 features priority encoding of the inputs to ensure that only the highest order data line is
encoded. Nine input lines are encoded to a four line BCD output. The implied decimal zero codition
requires no input condition as zero is encoded when all nine data lines are at a high logic level. All data
inputs and outputs are active at the low logic level.
Features
• High Speed Operation: t_pd = 14.5 ns typ (C_L = 50 pF)
• High Output Current: Fanout of 10 LSTTL Loads
• Wide Operating Voltage: V_CC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: I_CC (static) = 4 µA max (Ta = 25°C)
Function Table
Inputs
Outputs
12
3
4
5
6
7
8
9
D
C
B
A
HH
H
H
H
H
H
H
H
H
H
H
H
XX
X
X
X
X
X
X
L
L
H
H
L
XX
X
X
X
X
X
L
H
L
H
H
H
XX
X
X
X
X
L
H
H
H
L
L
L
XX
X
X
X
L
H
H
H
H
L
L
H
XX
X
X
L
H
H
H
H
H
L
H
L
XX
X
L
H
H
H
H
H
H
L
H
H
XX
L
H
H
H
H
H
H
H
H
L
L
XL
H
H
H
H
H
H
H
H
H
L
H
LH
H
H
H
H
H
H
H
H
H
H
L