AD9517-1BCPZ Analog Devices Inc, AD9517-1BCPZ Datasheet - Page 77
![12-Output Clock Generator With 2.5GHz VC](/photos/6/50/65022/cp-48-8_sml.jpg)
AD9517-1BCPZ
Manufacturer Part Number
AD9517-1BCPZ
Description
12-Output Clock Generator With 2.5GHz VC
Manufacturer
Analog Devices Inc
Type
Clock Generator, Fanout Distributionr
Datasheet
1.AD9517-1ABCPZ-RL7.pdf
(80 pages)
Specifications of AD9517-1BCPZ
Pll
Yes
Input
CMOS, LVDS, LVPECL
Output
CMOS, LVDS, LVPECL
Number Of Circuits
1
Ratio - Input:output
1:12
Differential - Input:output
Yes/Yes
Frequency - Max
2.65GHz
Divider/multiplier
Yes/No
Voltage - Supply
3.135 V ~ 3.465 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
48-LFCSP
Frequency-max
2.65GHz
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With
AD9517-1/PCBZ - BOARD EVAL FOR AD9517-1
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
CMOS CLOCK DISTRIBUTION
The AD9517 provides four clock outputs (OUT4 to OUT7)
that are selectable as either CMOS or LVDS level outputs.
When selected as CMOS, each output becomes a pair of CMOS
outputs, each of which can be individually turned on or off and
set as noninverting or inverting. These outputs are 3.3 V CMOS
compatible.
Whenever single-ended CMOS clocking is used, some of the
following general guidelines should be used.
Point-to-point nets should be designed such that a driver has
only one receiver on the net, if possible. This allows for simple
termination schemes and minimizes ringing due to possible
mismatched impedances on the net.
Series termination at the source is generally required to provide
transmission line matching and/or to reduce current transients
at the driver. The value of the resistor is dependent on the board
design and timing requirements (typically 10 Ω to 100 Ω is used).
CMOS outputs are also limited in terms of the capacitive load
or trace length that they can drive. Typically, trace lengths of less
than 3 inches are recommended to preserve signal rise/fall times
and preserve signal integrity.
Figure 74. Series Termination of CMOS Output
CMOS
10Ω
MICROSTRIP
(1.0 INCH)
60.4Ω
CMOS
Rev. B | Page 77 of 80
Termination at the far end of the PCB trace is a second option.
The CMOS outputs of the AD9517 do not supply enough current
to provide a full voltage swing with a low impedance resistive,
far-end termination, as shown in Figure 75. The far-end
termination network should match the PCB trace impedance and
provide the desired switching point. The reduced signal swing
may still meet receiver input requirements in some applications.
This can be useful when driving long trace lengths on less
critical nets.
Because of the limitations of single-ended CMOS clocking,
consider using differential outputs when driving high speed
signals over long traces. The AD9517 offers both LVPECL and
LVDS outputs that are better suited for driving long traces
where the inherent noise immunity of differential signaling
provides superior performance for clocking converters.
CMOS
10Ω
Figure 75. CMOS Output with Far-End Termination
50Ω
VS
100Ω
100Ω
CMOS
AD9517-1