Motorola MC74F259D, MC74F259N, MC54F259J Datasheet
4-133
FAST AND LS TTL DATA
8-BIT ADDRESSABLE LATCH
The MC54/74F259 is a high-speed 8-bit addressable latch designed for
general purpose storage applications in digital systems. It is a multifunctional
device capable of storing single line data in eight addressable latches, and
also a 1-of-8 decoder and demultiplexer with active HIGH outputs. The device
also incorporates an active LOW Common Clear for resetting all latches, as
well as an active LOW Enable.
• Serial-to-Parallel Conversion
• Eight Bits of Storage with Output of Each Bit Available
• Random (Addressable) Data Entry
• Active High Demultiplexing or Decoding Capability
• Easily Expandable
• Common Clear
FUNCTIONAL DESCRIPTION
The MC54/74F259 has four modes of operation as shown in the Mode Select Table. In the addressable latch mode, data on the Data line (D) is written
into the addressed latch. The addressed latch will follow the data input with
all non-addressed latches remaining in their previous states in the memory
mode. All the latches remain in their previous state and are unaffected by the
Data or Address inputs.
In the one-of-eight decoding or demultiplexing mode, the addressed output
will follow the state of the D input with all other outputs in the LOW state. In
the clear mode all outputs are LOW and unaffected by the address and data
inputs. When operating the MC54/74F259 as an addressable latch, changing
more than one bit of the address could impose a transient wrong address.
Therefore, this should only be done while in the memory mode. The Truth
Table below summarizes the operations of the MC54/74F259.
14 13 12 11 10 9
1 2 3 4 5 6
7
16 15
8
V
CC
A
0
MR
E D Q
7
Q
5
Q
6
Q
4
A1A2Q0Q1Q2Q3GND
CONNECTION DIAGRAM
MC54/74F259
8-BIT ADDRESSABLE LATCH
J SUFFIX
CERAMIC
CASE 620-09
N SUFFIX
PLASTIC
CASE 648-08
16
1
16
1
ORDERING INFORMATION
MC54FXXXJ Ceramic
MC74FXXXN Plastic
MC74FXXXD SOIC
16
1
D SUFFIX
SOIC
CASE 751B-03
FAST SCHOTTKY TTL
LOGIC SYMBOL
E
A
0
A
1
A
2
Q
0
Q2Q3Q4Q5Q6Q
7
Q
1
14
1
2
3
D
13
MR
15
4 5 6 7 9 10 11 12
4-134
FAST AND LS TTL DATA
MC54/74F259
GUARANTEED OPERATING RANGES
Symbol Parameter Min Typ Max Unit
V
CC
Supply Voltage 54, 74 4.5 5.0 5.5 V
54 –55 25 125
TAOperating Ambient Temperature Range
74 0 25 70
°C
I
OH
Output Current — High 54, 74 –1.0 mA
I
OL
Output Current — Low 54, 74 20 mA
Please note that this diagram is provided only for the understanding of logic
operations and should not be used to estimate propagation delays.
Q
7
Q
6
Q
5
Q
4
Q
3
Q
2
Q
1
Q
0
MR
A
2
A
1
A
0
D
E
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