SM802108 ClockWorks 10GbE & GbE (156.25MHz, 125MHz) Ultra-Low Jitter, LVPECL Frequency Synthesizer General Description Features The SM802108 is a member of the ClockWorks family of Generates two LVPECL clock outputs at 156.25MHz devices from Micrel and provides an extremely low-noise and two LVPECL clock outputs at 125MHz timing solution for GbE and 10GbE Ethernet clock signals. 2.5V or 3.3V operating range It is based upon a unique patented RotaryWave Typical phase jitter 156.25MHz architecture that provides very low phase noise. (1.875MHz to 20MHz): 110fs (typical) at 3.3V The device operates from a 3.3V or 2.5V power supply Industrial temperature range and synthesizes two LVPECL output clocks at 156.25MHz Green, RoHS, and PFOS compliant and another two at 125MHz. The SM802108 accepts a 25 MHz crystal or LVCMOS reference clock. Available in 24-pin 4mm 4mm QFN package Data sheets and support documentation can be found on Micrels web site at: www.micrel.com. Applications 10Gigabit Ethernet Gigabit Ethernet Block Diagram ClockWorks is a trademark of Micrel, Inc RotaryWave is a registered trademark of Multigig, Inc. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. SM802108 Ordering Information Part Number Marking Shipping Junction Temperature Range Package SM802108UMG 802108 Tube 40C to +85C 24-Pin QFN SM802108UMGR 802108 Tape and Reel 40C to +85C 24-Pin QFN Note: 1. Devices are Green, RoHS, and PFOS compliant. Pin Configuration 24-Pin QFN (Top View) Pin Description Pin Number Pin Name Pin Type Pin Level Pin Function 16, 17 /Q0, Q0 Differential Clock Outputs from Bank 1 O, (DIF) LVPECL 20, 21 /Q1, Q1 156.25MHz 23, 24 /Q2, Q2 Differential Clock Outputs from Bank 2 O, (DIF) LVPECL 3, 4 /Q3, Q3 125MHz 1 VDDO2 PWR Power Supply for Output Bank 2 2 VSSO2 PWR Power Supply Ground for Output Bank 2 PLL Bypass, Selects Output Source 0 = Normal PLL Operation 5 PLL BYPASS I, (SE) LVCMOS 1 = Output from Input Reference Clock or Crystal 45K pull-down Selects PLL Input Reference Source 6 XTAL SEL I, (SE) LVCMOS 0 = REF IN, 1 = XTAL, 45K pull-up M9999-012111-A January 2011 2 hbwhelp micrel.com or (408) 955-1690