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 devices from Micrel and provides an extremely low-noise timing solution for GbE and 10GbE Ethernet clock signals. It is based upon a unique patented RotaryWave® architecture that provides very low phase noise. The device operates from a 3.3V or 2.5V power supply and synthesizes two LVPECL output clocks at 156.25MHz and another two at 125MHz. The SM802108 accepts a 25 MHz crystal or LVCMOS reference clock. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. • Generates two LVPECL clock outputs at 156.25MHz and two LVPECL clock outputs at 125MHz • 2.5V or 3.3V operating range • Typical phase jitter @ 156.25MHz (1.875MHz to 20MHz): 110fs (typical) at 3.3V • Industrial temperature range • Green, RoHS, and PFOS compliant • Available in 24-pin 4mm × 4mm QFN package 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 • http://www.micrel.com January 2011 M9999-012111-A [email protected] or (408) 955-1690 Micrel, Inc. SM802108 Ordering Information Marking Shipping Junction Temperature Range Package SM802108UMG Part Number 802108 Tube –40°C to +85°C 24-Pin QFN SM802108UMGR 802108 Tape and Reel –40°C to +85°C 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 O, (DIF) LVPECL O, (DIF) LVPECL Pin Function 16, 17 /Q0, Q0 20, 21 /Q1, Q1 23, 24 /Q2, Q2 3, 4 /Q3, Q3 1 VDDO2 PWR Power Supply for Output Bank 2 2 VSSO2 PWR Power Supply Ground for Output Bank 2 Differential Clock Outputs from Bank 1 156.25MHz Differential Clock Outputs from Bank 2 125MHz PLL Bypass, Selects Output Source 5 PLL_BYPASS I, (SE) 0 = Normal PLL Operation LVCMOS 1 = Output from Input Reference Clock or Crystal 45KΩ pull-down 6 January 2011 XTAL_SEL I, (SE) Selects PLL Input Reference Source LVCMOS 0 = REF_IN, 1 = XTAL, 45KΩ pull-up 2 M9999-012111-A [email protected] or (408) 955-1690 Micrel, Inc. SM802108 Pin Description (Continued) Pin Number Pin Name 7, 12, 15, 19 TEST Pin Type Pin Level Pin Function 8 VDD PWR 9 REF_IN I, (SE) LVCMOS 10 XIN I, (SE) 12pF crystal 11 XOUT O, (SE) 12pF crystal 13, 14 VSS PWR 18 VDDO1 PWR Power Supply for Output Bank 1 22 VSSO1 PWR Power Supply Ground for Output Bank 1 Factory Test Pins, Do not connect anything to these pins. Core Power Supply Reference Clock Input See Fig. 5. Crystal Reference Output, no load caps needed. See Fig. 5. Core Power Supply Ground Application Information Truth Table Input Reference When operating with a crystal input reference, do not apply a switching signal to REF_IN. Crystal Layout Keep the layers under the crystal as open as possible. Do not place switching signals or noisy supplies under the crystal. January 2011 Crystal Reference Input, no load caps needed. 3 PLL_BYPASS XTAL_SEL INPUT OUTPUT 0 − − PLL 1 − − XTAL/REF_IN − 0 REF_IN − − 1 XTAL − M9999-012111-A [email protected] or (408) 955-1690 Micrel, Inc. SM802108 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VDD, VDDOx) ........................................+4.6V Input Voltage (VIN). ............................. –0.50V to VDD + 0.5V Lead Temperature (soldering, 20sec.)....................... 260°C Case Temperature ..................................................... 115°C Storage Temperature (Ts) .........................–65°C to +150°C Supply Voltage (VDD, VDDOx) ................. +2.375V to +3.465V Ambient Temperature (TA) .......................... –40°C to +85°C Junction Thermal Resistance(3) QFN (θJA) Still-Air.........................................................50°C/W QFN (ψJB) Junction-to-Board .......................................30°C/W DC Electrical Characteristics(4) VDD = VDDO1/2 = 3.3V ±5% or 2.5V ±5% VDD = 3.3V ±5%, VDDO1/2 = 3.3V ±5% or 2.5V ±5% TA = −40°C to +85°C. Symbol Parameter VDD, VDDOx 2.5V Operating Voltage VDD, VDDOx 3.3V Operating Voltage Condition IDD Supply current VDD + VDDO Outputs open; REF_IN source, XTAL_SEL = 0 IDD Supply current VDD + VDDO Outputs open; CRYSTAL source, XTAL_SEL = 1 Min. Typ. Max. Units 2.375 2.5 2.625 V 3.135 3.3 3.465 V 130 165 mA 145 185 mA LVPECL DC Electrical Characteristics(4) VDD = VDDO1/2 = 3.3V ±5% or 2.5V ±5% VDD = 3.3V ±5%, VDDO1/2 = 3.3V ±5% or 2.5V ±5% TA = −40°C to +85°C. RL = 50Ω to VDDO − 2V Symbol Parameter Min. Typ. Max. Units VOH Output High Voltage Condition VDDO – 1.145 VDDO – 0.97 VDDO – 0.845 V VOL Output Low Voltage VDDO – 1.945 VDDO – 1.77 VDDO – 1.645 V VSWING Output Voltage Swing 0.6 0.8 1.0 V Note: 1. Permanent device damage may occur if absolute maximum ratings are exceeded. This is a stress rating only and functional operation is not implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. 2. The data sheet limits are not guaranteed if the device is operated beyond the operating ratings. 3. Package thermal resistance assumes exposed pad is soldered (or equivalent) to the devices most negative potential on the PCB. 4. The circuit is designed to meet the AC and DC specifications shown in the above table(s) after thermal equilibrium has been established. January 2011 4 M9999-012111-A [email protected] or (408) 955-1690 Micrel, Inc. SM802108 LVCMOS (PLL_BYPASS, XTAL_SEL) DC Electrical Characteristics(4) VDD = 3.3V ±5%, or 2.5V ±5%, TA = −40°C to +85°C. Symbol Parameter Condition VIH Input High Voltage VIN Input Low Voltage IIH Input High Current VDD = VIN = 3.465V IIL Input Low Current VDD = 3.465V, VIN = 0V Min. Typ. Max. Units 2 VDD + 0.3 V −0.3 0.8 V 150 μA −5 μA REF_IN DC Electrical Characteristics(4) VDD = 3.3V ±5%, or 2.5V ±5%, TA = −40°C to +85°C. Symbol Parameter Condition VIH Input High Voltage VIL Input Low Voltage IIN Input Current XTAL_SEL = VIL, VIN = 0V to VDD IIN Input Current XTAL_SEL = VIH, VIN = VDD Min. Typ. Max. Units 1.1 VDD + 0.3 V −0.3 0.6 V −5 5 μA 20 µA Crystal Characteristics NDK NX2520SA Parameter Condition Mode of Oscillation Frequency Equivalent Series Resistance (ESR) Shunt Capacitor, C0 Correlation Drive Level 12pF Load January 2011 Min. Typ. Max. Fundamental, Parallel Resonant 25 50 3 7 100 300 5 Units MHz Ω pF uW M9999-012111-A [email protected] or (408) 955-1690 Micrel, Inc. SM802108 AC Electrical Characteristics(4, 5) VDD = VDDO1/2 = 3.3V ±5% or 2.5V ±5% VDD = 3.3V ±5%, VDDO1/2 = 3.3V ±5% or 2.5V ±5% TA = −40°C to +85°C. RL = 50Ω to VDDO − 2V Symbol Parameter Condition Min. Typ. FOUT1 Output Frequency 1 156.25 FOUT2 Output Frequency 2 125 Ppm Output ppm Variation FREF Reference Input Frequency TR/TF LVPECL Output Rise/Fall Time ODC Output Duty Cycle TSKEW Output-to-Output Skew TLOCK PLL Lock Time Crystal reference. Note 6 RMS Phase Jitter Units MHz 50 25 20% – 80% 175 350 48 50 52 % 45 ps 20 ms Spurious Noise Components 6.25MHz 25MHz ps 110 250 (8) 125MHz Integration Range (1.875MHz – 20MHz) Integration Range (12kHz – 20MHz) ppm MHz 80 Within bank. Note 7 156.25MHz Integration Range (1.875MHz – 20MHz) Integration Range (12kHz – 20MHz) Tjit(∅) −50 Max. fs 110 250 -73 -58 dBc Notes: 5. All phase noise measurements were taken with an Agilent 5052B phase noise system. 6. Crystal tolerance at room less than +/- 15ppm, over temp less than +/- 20ppm. 7. Defined as skew between outputs at the same supply voltage and with equal load conditions and same frequency; Measured at the output differential crossing points. 8. Measured using 25MHz crystal as the input reference source. January 2011 6 M9999-012111-A [email protected] or (408) 955-1690 Micrel, Inc. SM802108 Phase Noise Plots Phase Noise Plot: 156.25MHz, 1.875MHz − 20MHz 108fS Phase Noise Plot: 156.25MHz, 12kHz − 20MHz 253fS January 2011 7 M9999-012111-A [email protected] or (408) 955-1690 Micrel, Inc. SM802108 Phase Noise Plots (Continued) Phase Noise Plot: 125MHz, 1.875MHz − 20MHz 111fS Phase Noise Plot: 125MHz, 12kHz − 20MHz 257fS January 2011 8 M9999-012111-A [email protected] or (408) 955-1690 Micrel, Inc. SM802108 Figure 1. Duty Cycle TIming Figure 2. All Outputs Rise/Fall Time Figure 3. RMS Phase/Noise/Jitter January 2011 9 M9999-012111-A [email protected] or (408) 955-1690 Micrel, Inc. SM802108 Figure 4. LVPECL Output Load and Test Circuit Figure 5. Crystal Input Interface January 2011 10 M9999-012111-A [email protected] or (408) 955-1690 Micrel, Inc. SM802108 Package Information 24-Pin QFN MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2011 Micrel, Incorporated. January 2011 11 M9999-012111-A [email protected] or (408) 955-1690