74F148SCX Fairchild Semiconductor, 74F148SCX Datasheet - Page 2

• Manufacturer Part Number: 74F148SCX
• Manufacturer: Fairchild Semiconductor

Specifications of 74F148SCX

• Lead Free Status / RoHS Status: Compliant

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Unit Loading/Fan Out
Functional Description
The F148 8-input priority encoder accepts data from eight
active LOW inputs (I
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-
Logic Diagram
Please note that this diagram is provided only for the understanding of logic
operations and should not be used to estimate propagation delays.
I
I
EI
EO
GS
A
0
1
Pin Names
–I
0
0
–A
–I
7
7
2
) and provides a binary represen-
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)
Description
2
puts.A Group Signal output (GS) and Enable Output (EO)
are provided along with the three priority data outputs (A
A
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.
Application
1
, A
0
). GS is active LOW when any input is LOW: this
HIGH/LOW
50/33.3
50/33.3
50/33.3
1.0/1.0
1.0/2.0
1.0/1.0
U.L.
16-Input Priority Encoder
Output I
20 A/ 0.6 mA
20 A/ 1.2 mA
20 A/ 0.6 mA
Input I
1 mA/20 mA
1 mA/20 mA
1 mA/20 mA
IH
OH
/I
/I
IL
OL
2
,