MC100E211 ON Semiconductor, MC100E211 Datasheet - Page 5

• Manufacturer Part Number: MC100E211
• Description: 1:6 DIFFERENTIAL CLOCK DISTRIBUTION CHIP
• Manufacturer: ON Semiconductor

Differential versus Single-Ended Use
of the E211 the device must be used in the differential mode.
In the single-ended mode the propagation delays are
dependent on the relative position of the V BB switching
reference. Any V BB offset from the center of the input swing
will add delay to either the T PLH or T PHL and subtract delay
from the other. This increase and decrease in delay will lead
to an increase in the duty cycle skew and thus part-to-part
skew. The within-device skew will be independent of the V BB
and therefore will be the same regardless of whether the
device is driven differentially or single-endedly.
skew are not important the advantages of single-ended clock
distribution may lead to its use. Using single-ended
interconnect will reduce the number of signal traces to be
routed, but remember that all of the complimentary outputs
still need to be terminated therefore there will be no reduction
in the termination components required. To use the E211 with
a single-ended input the arrangement pictured in Figure 2b
should be used. If the input to the differential CLK inputs are
AC coupled as pictured in Figure 2a the dependence on a
centered V BB reference is removed. The situation pictured
will ensure that the input is centered around the bias set by
the V BB . As a result when AC coupled the AC specification
limits for a differential input can be used. For more
information on AC coupling please refer to the interfacing
section of the design guide in the ECLinPS data book.
Using the Enable Pins
enables (ENx) are synchronous to the CLK or SCLK input
depending on which is selected. The active low signals are
clocked into the enable flip flops on the negative edges of the
E211 clock inputs. In this way the devices will only be
disabled when the outputs are already in the LOW state. The
internal propagation delays are such that the delay to the
output through the distribution buffers is less than that
through the enable flip flops. This will ensure that the
disabling of the device will not slice any time off the clock
ECLinPS and ECLinPS Lite
DL140 — Rev 4
As can be seen from the data sheet, to minimize the skew
For applications where part-to-part skew or duty cycle
Both the common enable (CEN) and the individual
APPLICATIONS INFORMATION
2–5
pulse. On initial power up the enable flip flops will randomly
attain a stable state, therefore precautions should be taken
on initial power up to ensure the E211 is in the desired state.
IN
0.001 F
Figure 2b. Single-Ended Input
IN
IN
IN
Figure 2a. AC Coupled Input
V BB
V BB
50
MC10E211 MC100E211
0.01 F
0.01 F
MOTOROLA