MAX3674 Datasheet, PDF (1/19 Pages) Maxim Integrated Products – High-Performance, Dual-Output, Network Clock Synthesizer

19-2483; Rev 0; 12/07
High-Performance, Dual-Output, Network Clock
Synthesizer
General Description
The MAX3674 is a high-performance network clock
synthesizer IC for networking, computing, and telecom
applications. It integrates a crystal oscillator, a low-
noise phase-locked loop (PLL), programmable dividers,
and high-frequency LVPECL output buffers. The PLL
generates a high-frequency clock based on a low-fre-
quency reference clock provided by the on-chip crystal
oscillator or an external LVCMOS clock. The MAX3674
has excellent period jitter, cycle-to-cycle jitter, and sup-
ply noise rejection performance. With output frequen-
cies programmable from 21.25MHz to 1360MHz and
support of two differential PECL output signals, the
device provides a versatile solution for the most
demanding clock applications.
Programming is accomplished through a 2-wire I²C bus
or parallel interface that can change the output fre-
quency on demand for frequency margining. Both
LVPECL outputs have synchronous stop functionality,
and the PLL has a LOCK indicator output. The
MAX3674 operates from a +3.3V supply and typically
consumes 396mW. The device is packaged in a 48-pin
LQFP, and the operating temperature range is from
-40°C to +85°C.
Applications
Ethernet Network ASIC Clock Generation
Storage Area Network ASIC Clocking
Optical Network ASIC Clocking
Programmable Clock Source for Server, Comput-
ing, or Communication Systems
Frequency Margining
16MHz
SERIAL I²C
INTERFACE
PARALLEL
INTERFACE
PLL DIVIDER
CONTROLS
+3.3V +3.3V +3.3V
REF_SEL V_CC V_{CC_PLL}
REF_CLK
QA
QA
XTAL1
QB
XTAL2
SDA
SCL
M[9:0]
NA[2:0]
NB
P
QB
MAX3674
CLK_STOPA
CLK_STOPB
BYPASS
PLOAD MR GND LOCK
Features
♦ 21.25MHz to 1360MHz Programmable PLL Synthe-
sized Output Clocks
♦ Two Differential LVPECL-Compatible Outputs
♦ Cycle-to-Cycle Jitter 1.6ps RMS and Period Jitter
0.9ps RMS at 500MHz
♦ On-Chip Crystal Oscillator or Selectable
LVCMOS-Compatible Reference Clock Input
♦ Excellent Power-Supply Noise Rejection
♦ Parallel or 2-Wire I²C Programming Interface
♦ Lock Indicator Output
♦ +3.3V Power Supply
♦ Power Consumption: 396mW at 3.3V
♦ 48-Pin LQFP Pb-Free Package
♦ -40°C to +85°C Temperature Range
Ordering Information
PART
TEMP RANGE
MAX3674ECM+ -40°C to +85°C
+Denotes a lead-free package.
PIN-PACKAGE
48 LQFP
Pin Configuration appears at end of data sheet.
LVPECL
OUTPUTS
Z = 50Ω
Typical Application Circuit
+3.3V
130Ω
NETWORK
ASIC
82Ω
+3.3V
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.