MC14521 ONSEMI [ON Semiconductor], MC14521 Datasheet - Page 7

• Manufacturer Part Number: MC14521
• Description: 24-Stage Frequency Divider
• Manufacturer: ONSEMI [ON Semiconductor]

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included for the reduction of test time required to
included for the reduction of test time required to
exercise all 24 counter stages. This test function
divides the counter into three 8–stage sections,
and 255 counts are loaded in each of the
8–stage sections in parallel. All flip–flops are
now at a logic “1”. The counter is now returned
to the normal 24–stages in series configuration.
One more pulse is entered into Input 2 (In 2)
which will cause the counter to ripple from an all
“1” state to an all “0” state.
A test function (see Figure 8) has been
g
FUNCTIONAL TEST SEQUENCE
Reset
1
0
Inputs
http://onsemi.com
MC14521B
In 2
—
—
—
0
1
0
1
1
0
0
1
1
0
7
Out 2
—
—
—
0
1
0
1
1
0
0
0
0
1
V
G d
Gnd
V
SS
DD
Outputs
V
Gnd
V
DD
DD
Q18 thru
Q24
0
1
1
1
1
1
0
Counter is in three 8–stage
sections in parallel mode
Counter is reset. In 2 and
Out 2 are connected
together
First “0” to “1” transition
on In 2, Out 2 node.
255 “0” to “1” transitions
are clocked into this In 2,
Out 2 node.
The 255th “0” to “1”
transition.
Counter converted back to
24–stages in series mode.
Out 2 converts back to an
output.
Counter ripples from an all
“1” state to an all “0” stage.
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