6-Output Clock Generator with
Integrated 2.0 GHz VCO
Data Sheet
Rev. B
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FEATURES
Low phase noise, phase-locked loop (PLL)
On-chip VCO tunes from 1.75 GHz to 2.25 GHz
External VCO/VCXO to 2.4 GHz optional
1 differential or 2 single-ended reference inputs
Reference monitoring capability
Automatic revertive and manual reference
switchover/holdover modes
Accepts LVPECL, LVDS, or CMOS references to 250 MHz
Programmable delays in path to PFD
Digital or analog lock detect, selectable
3 pairs of 1.6 GHz LVPECL outputs
Each output pair shares a 1-to-32 divider with coarse
phase delay
Additive output jitter: 225 fs rms
Channel-to-channel skew paired outputs of <10 ps
Automatic synchronization of all outputs on power-up
Manual output synchronization available
Available in a 48-lead LFCSP
APPLICATIONS
Low jitter, low phase noise clock distribution
10/40/100 Gb/sec networking line cards, including SONET,
Synchronous Ethernet, OTU2/3/4
Forward error correction (G.710)
Clocking high speed ADCs, DACs, DDSs, DDCs, DUCs, MxFEs
High performance wireless transceivers
ATE and high performance instrumentation
GENERAL DESCRIPTION
The
AD9518-31 provides a multi-output clock distribution
function with subpicosecond jitter performance, along with an
on-chip PLL and VCO. The on-chip VCO tunes from 1.75 GHz
to 2.25 GHz. Optionally, an external VCO/VCXO of up to
2.4 GHz can be used.
The
AD9518-3 emphasizes low jitter and phase noise to
maximize data converter performance, and it can benefit other
applications with demanding phase noise and jitter requirements.
The
AD9518-3 features six LVPECL outputs (in three pairs).
The LVPECL outputs operate to 1.6 GHz.
For applications that require additional outputs, a crystal
reference input, zero-delay, or EEPROM for automatic
configuration at startup, the
AD9520 and
AD9522 are available.
FUNCTIONAL BLOCK DIAGRAM
REFIN
REF1
REF2
CLK
LF
SW
IT
C
H
O
VE
R
AN
D
M
O
NI
T
O
R
PL
L
DIVIDER
AND MUXs
CP
VCO
STATUS
MONITOR
LVPECL
SERIAL CONTROL PORT
AND
DIGITAL LOGIC
AD9518-3
OUT0
OUT1
OUT2
OUT3
OUT4
OUT5
DIV/Φ
LVPECL
0
64
32
-0
01
Figure 1.
but have a different combination of outputs.
Each pair of outputs has dividers that allow both the divide
ratio and coarse delay (or phase) to be set. The range of division
for the LVPECL outputs is 1 to 32.
The
AD9518-3 is available in a 48-lead LFCSP and can be
operated from a single 3.3 V supply. An external VCO, which
requires an extended voltage range, can be accommodated
by connecting the charge pump supply (VCP) to 5 V. A separate
LVPECL power supply can be from 2.5 V to 3.3 V (nominal).
The
AD9518-3 is specified for operation over the industrial
range of 40°C to +85°C.
1
AD9518 is used throughout the data sheet to refer to all the members of
the
AD9518 family. However, when
AD9518-3 is used, it refers to that specific