MC10EP016FA(2002) View Datasheet(PDF) - ON Semiconductor
Part Name
Description
Manufacturer
MC10EP016FA Datasheet PDF : 12 Pages
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MC10EP016, MC100EP016
Applications Information (continued)
EP01
Q0 to Q7
LO CE
PE
EP016
LSB
CLK
CLK
TC
P0 to P7
Q0 to Q7
CE
PE
EP016
CLK
CLK
TC
P0 to P7
EP01
Q0 to Q7
CE
PE
EP016
CLK
CLK
TC
P0 to P7
EP01
CLK
CLK
Figure 6. 32-Bit Cascaded EP016 Programmable Divider
Q0 to Q7
CE
PE
EP016
MSB
CLK
CLK
TC
P0 to P7
Figure 6 shows a typical block diagram of a 32-bit divider
chain. Once again to maximize the frequency of operation
EP01 OR gates were used. For lower frequency applications
a slower OR gate could replace the EP01. Note that for a
16-bit divider the OR function feeding the PE (program
enable) input CANNOT be replaced by a wire OR tie as the
TC output of the least significant EP016 must also feed the
CE input of the most significant EP016. If the two TC
outputs were OR tied the cascaded count operation would
not operate properly. Because in the cascaded form the PE
feedback is external and requires external gating, the
maximum frequency of operation will be significantly less
than the same operation in a single device.
Maximizing EP016 Count Frequency
The EP016 device produces 9 fast transitioning
single–ended outputs, thus VCC noise can become
significant in situations where all of the outputs switch
simultaneously in the same direction. This VCC noise can
negatively impact the maximum frequency of operation of
the device. Since the device does not need to have the Q
outputs terminated to count properly, it is recommended that
if the outputs are not going to be used in the rest of the system
they should be left unterminated. In addition, if only a subset
of the Q outputs are used in the system only those outputs
should be terminated. Not terminating the unused outputs
will not only cut down the VCC noise generated but will also
save in total system power dissipation. Following these
guidelines will allow designers to either be more aggressive
in their designs or provide them with an extra margin to the
published data book specifications.
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