HIT HD74HC147 Datasheet
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: tpd = 14.5 ns typ (CL = 50 pF)
• High Output Current: Fanout of 10 LSTTL Loads
• Wide Operating Voltage: VCC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)
Function Table
Inputs Outputs
123456789DCBA
HHHHHHHHHHHHH
XXXXXXXXLLHHL
XXXXXXXLHLHHH
XXXXXXLHHHLL L
XXXXXL HHHHLL H
XXXXL HHHHHLHL
XXXL HHHHHHLHH
XXLHHHHHHHHL L
XL HHHHHHHHHLH
LHHHHHHHHHHHL
HD74HC147
Pin Arrangement
Inputs
Outputs
GND
1
4
4
2
5
3
6
4
7
5
8
6
C
7
B
8
5
6
7
8
C
B
(Top view)
D
3
2
1
9
A
16
15
14
13
12
11
10
V
CC
NC
D
Output
3
2
Inputs
1
9
Output
A
9
2
HD74HC147
DC Characteristics
Ta = –40 to
Ta = 25°C
Item Symbol V
Input voltage V
IH
(V) Min Typ Max Min Max Unit Test Conditions
CC
2.0 1.5 — — 1.5 — V
4.5 3.15 — — 3.15 —
6.0 4.2 — — 4.2 —
V
IL
2.0 — — 0.5 — 0.5 V
4.5 — — 1.35 — 1.35
6.0 — — 1.8 — 1.8
Output voltage V
OH
2.0 1.9 2.0 — 1.9 — V Vin = VIH or VILIOH = –20 µA
4.5 4.4 4.5 — 4.4 —
6.0 5.9 6.0 — 5.9 —
4.5 4.18 — — 4.13 — IOH = –4 mA
6.0 5.68 — — 5.63 — IOH = –5.2 mA
V
OL
2.0 — 0.0 0.1 — 0.1 V Vin = VIH or VILIOL = 20 µA
4.5 — 0.0 0.1 — 0.1
6.0 — 0.0 0.1 — 0.1
4.5 — — 0.26 — 0.33 IOL = 4 mA
6.0 — — 0.26 — 0.33 IOL = 5.2 mA
Input current Iin 6.0 — — ±0.1 — ±1.0 µA Vin = VCC or GND
Quiescent supply
I
CC
6.0 — — 4.0 — 40 µA Vin = VCC or GND, Iout = 0 µA
current
+85°C
3
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