74F148SJ PDF даташит
Спецификация 74F148SJ изготовлена «Fairchild Semiconductor» и имеет функцию, называемую «8-Line to 3-Line Priority Encoder». |
|
Детали детали
Номер произв | 74F148SJ |
Описание | 8-Line to 3-Line Priority Encoder |
Производители | Fairchild Semiconductor |
логотип |
6 Pages
No Preview Available ! |
April 1988
Revised July 1999
74F148
8-Line to 3-Line Priority Encoder
General Description
The F148 provides three bits of binary coded output repre-
senting 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.
Features
s Encodes eight data lines in priority
s Provides 3-bit binary priority code
s Input enable capability
s Signals when data is present on any input
s Cascadable for priority encoding of n bits
Ordering Code:
Order Number Package Number
Package Description
74F148SC
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
74F148SJ
M16D
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74F148PC
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Logic Symbols
Connection Diagram
IEEE/IEC
Truth Table
Inputs
Outputs
EI I0 I1 I2 I3 I4 I5 I6 I7 GS A0 A1 A2 EO
HXXXXXXXX H HHH H
LHHHHHHHH H HHH L
LXXXXXXXL L L L L H
LXXXXXXLH L HL L H
L XXXXX LHH L LHL H
L XXXX LHHH L HHL H
L XXX LHHHH L L LH H
L XX LHHHHH L H LH H
L X LHHHHHH L LHH H
L LHHHHHHH L HHH H
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
© 1999 Fairchild Semiconductor Corporation DS009480
www.fairchildsemi.com
No Preview Available ! |
Unit Loading/Fan Out
Pin Names
Description
I0
I1–I7
EI
EO
GS
A0–A2
Priority Input (Active LOW)
Priority Inputs (Active LOW)
Enable Input (Active LOW)
Enable Output (Active LOW)
Group Signal Output (Active LOW)
Address Outputs (Active LOW)
U.L.
HIGH/LOW
1.0/1.0
1.0/2.0
1.0/1.0
50/33.3
50/33.3
50/33.3
Input IIH/IIL
Output IOH/IOL
20 µA/−0.6 mA
20 µA/−1.2 mA
20 µA/−0.6 mA
−1 mA/20 mA
−1 mA/20 mA
−1 mA/20 mA
Functional Description
The F148 8-input priority encoder accepts data from eight
active LOW inputs (I0–I7) and provides a binary represen-
tation 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 high-
est priority. A HIGH on the Enable Input (EI) will force all
outputs to the inactive (HIGH) state and allow new data to
settle without producing erroneous information at the out-
puts.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.
Logic Diagram
Application
16-Input Priority Encoder
Please note that this diagram is provided only for the understanding of logic
operations and should not be used to estimate propagation delays.
www.fairchildsemi.com
2
No Preview Available ! |
Absolute Maximum Ratings(Note 1)
Storage Temperature
−65°C to +150°C
Ambient Temperature under Bias
−55°C to +125°C
Junction Temperature under Bias
−55°C to +150°C
VCC Pin Potential to Ground Pin
Input Voltage (Note 2)
−0.5V to +7.0V
−0.5V to +7.0V
Input Current (Note 2)
−30 mA to +5.0 mA
Voltage Applied to Output
in HIGH State (with VCC = 0V)
Standard Output
3-STATE Output
−0.5V to VCC
−0.5V to +5.5V
Current Applied to Output
in LOW State (Max)
twice the rated IOL (mA)
Recommended Operating
Conditions
Free Air Ambient Temperature
Supply Voltage
0°C to +70°C
+4.5V to +5.5V
Note 1: Absolute maximum ratings are values beyond which the device
may be damaged or have its useful life impaired. Functional operation
under these conditions is not implied.
Note 2: Either voltage limit or current limit is sufficient to protect inputs.
DC Electrical Characteristics
Symbol
Parameter
Min
Typ
Max
Units
VCC
Conditions
VIH
VIL
VCD
VOH
VOL
IIH
IBVI
ICEX
VID
IOD
Input HIGH Voltage
Input LOW Voltage
Input Clamp Diode Voltage
Output HIGH
Voltage
Output LOW
Voltage
Input HIGH
Current
Input HIGH Current
Breakdown Test
Output High
Leakage Current
Input Leakage
Test
Output Leakage
Circuit Current
10% VCC
5% VCC
10% VCC
2.0
2.5
2.7
4.75
V Recognized as a HIGH Signal
0.8 V
Recognized as a LOW Signal
−1.2 V Min IIN = −18 mA
V Min IOH = −1 mA
IOH = −1 mA
0.5 V Min IOL = 20 mA
5.0 µA Max VIN = 2.7V
7.0 µA Max VIN = 7.0V
50 µA Max VOUT = VCC
3.75
V
µA
0.0 IID = 1.9 µA
All Other Pins Grounded
0.0 VIOD = 150 mV
All Other Pins Grounded
IIL
IOS
ICCH
ICCL
Input LOW
Current
Output Short-Circuit Current
Power Supply Current
Power Supply Current
−60
−0.6 mA Max VIN = 0.5V (I0, EI)
−1.2
mA
VIN = 0.5V (I1–I7)
−150 mA Max VOUT = 0V
35 mA Max VO = HIGH
35 mA Max VO = LOW
3 www.fairchildsemi.com
Скачать PDF:
[ 74F148SJ.PDF Даташит ]
Номер в каталоге | Описание | Производители |
74F148SC | 8-Line to 3-Line Priority Encoder | Fairchild Semiconductor |
74F148SJ | 8-Line to 3-Line Priority Encoder | Fairchild Semiconductor |
Номер в каталоге | Описание | Производители |
TL431 | 100 мА, регулируемый прецизионный шунтирующий регулятор |
Unisonic Technologies |
IRF840 | 8 А, 500 В, N-канальный МОП-транзистор |
Vishay |
LM317 | Линейный стабилизатор напряжения, 1,5 А |
STMicroelectronics |
DataSheet26.com | 2020 | Контакты | Поиск |