SM843031-01
ClockWorks™ 10-Gigabit Ethernet, 312.5MHz, Ultra-Low Jitter LVPECL Clock Frequency Synthesizer
General Description
The SM843031-01 is a 10-Gigabit Ethernet, 312.5MHz LVPECL clock frequency synthesizer and a member of the ClockWorks™ family of devices from Micrel. It provides a low-noise timing solution for high-speed, high-accuracy synthesis of clock signals. It includes a patented RotaryWave® architecture that provides a very stable clock with very low noise. Power supplies of either 2.5V or 3.3V are supported, with superior jitter and phase noise performance. The device synthesizes a 312.5MHz, low-noise, LVPECL output for Ethernet applications. The crystal reference frequency used is 25MHz. The SM843031-01 is an excellent replacement for IDT FemtoClocks®, with improved waveform integrity, and jitter. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com.
Features
• Generates a low noise LVPECL output • 2.5V or 3.3V operating range • Typical phase jitter @ 312.5MHz (1.875MHz to 20MHz): 119 fs (typical) @ 3.3V • Crystal frequency: 25MHz • 312.5MHz Output frequency • Industrial temperature range • Green-, RoHS-, and PFOS-compliant • Available in 8-pin TSSOP
Applications
• Gigabit Ethernet • 10-Gigabit Ethernet
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Block Diagram
ClockWorks is a trademark of Micrel, Inc. RotaryWave is a registered trademark of Multigig, Inc. FemtoClocks is a registered trademark of IDT, 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
October 2010
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Micrel, Inc.
SM843031-01
Ordering Information(1)
Part Number SM843031-01KA SM843031-01KA TR
(2)
Package Type K-8 K-8
Operating Range Industrial Industrial
Package Marking 843031-01 843031-01
Notes: 1. Devices are Green-, RoHS-, and PFOS-compliant. 2. Tape and Reel.
Pin Configuration
8-Pin TSSOP (K-8) (Top View)
Pin Description
Pin Number 1 2 3 4 5 6 7 8 Pin Name VDDA VEE XTAL_OUT XTAL_IN NC /Q0 Q0 VDD Pin Type PWR PWR O, (SE) I, (SE) − O, (DIF) O, (DIF) PWR LVPECL LVPECL 12pF crystal 12pF crystal Pin Level Pin Function Analog 2.5V or 3.3V Power Supply. No filter resistor needed. Ground. Crystal Reference Output, no load caps needed. Crystal Reference Input, no load caps needed. No Connect Differential Clock Output Differential Clock Output 2.5V or 3.3V Power Supply
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Micrel, Inc.
SM843031-01
Absolute Maximum Ratings(1)
Supply Voltage (VDDA, VDD,) ........................................+4.6V Input Voltage (VIN) ............................... −0.50V to VDD + 0.5V LVPECL Output Current (IOUT) Continuous............................................................50mA Surge ..................................................................100mA Lead Temperature (soldering, 20sec.)....................... 260°C Case Temperature ..................................................... 115°C Storage Temperature (Ts) ......................... −65°C to +150°C
Operating Ratings(2)
Supply Voltage (VDD, VDDA) ................... +2.375V to +3.465V Ambient Temperature (TA) .......................... –40°C to +85°C Junction Thermal Resistance TSSOP (θJA)(Still Air).......................................141°C/W
DC Electrical Characteristics(3)
VDD = VDDA = 3.3V ±5%; TA = –40°C to +85°C, unless noted. Symbol VDD VDDA IDDA IEE Parameter Core Supply Voltage Analog Supply Voltage Analog Supply Current Total Supply Current Included in IEE No load Condition Min. 3.135 3.135 Typ. 3.30 3.30 50 95 Max. 3.465 3.465 60 115 Units V V mA mA
VDD = VDDA = 2.5V ±5%; TA = –40°C to +85°C, unless noted. Symbol VDD VDDA IDDA IEE Parameter Core Supply Voltage Analog Supply Voltage Analog Supply Current Total Supply Current Included in IEE No load Condition Min. 2.375 2.375 Typ. 2.50 2.50 50 87 Max. 2.625 2.625 60 105 Units V V mA mA
LVPECL DC Electrical Characteristics(3, 4)
VDD = VDDA = 2.5V ±5% or 3.3V ±5%, TA = –40°C to +85°C, unless noted. Symbol VOH VOL VSWING
Notes: 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. The data sheet limits are not guaranteed if the device is operated beyond the operating ratings. The circuit is designed to meet the DC specifications shown in the above table after thermal equilibrium has been established with a transverse airflow greater than 500 lfpm.. See Figure 4 for load test circuit example.
Parameter Output High Voltage Output Low Voltage Peak-to-Peak Output Voltage Swing
Condition 50Ω to VDD-2V 50Ω to VDD-2V
Min. VDD – 1.145 VDD – 1.945 0.6
Typ. VDD – 0.97 VDD – 1.77 0.8
Max. VDD – 0.845 VDD – 1.645 1.0
Units V V V
2. 3. 4.
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Micrel, Inc.
SM843031-01
AC Electrical Characteristics(5)
VDD = VDDA = 2.5V ±5% or 3.3V ±5%, TA = –40°C to +85°C, unless noted. Symbol FOUT tJITTER tR, tF ODC
Note: 5. The circuit is designed to meet the AC specifications shown in the above table(s) after thermal equilibrium has been established with a transverse airflow greater than 500 lfpm.
Parameter Output Frequency RMS Phase Jitter (Output = 312.5 MHz) Output Rise/Fall Time Output Duty Cycle
Condition Integration Range: 1.875MHz to 20MHz 20% to 80%
Min.
Typ. 312.5 119
Max.
Units MHz fs
80 48
175 50
350 52
ps %
Crystal Characteristics
Parameter Mode of Oscillation Frequency Equivalent Series Resistance (ESR) Shunt Capacitor, C0 Correlation Drive Level 3 100 Condition 12pF Load Min. Typ. 25 50 7 300 Max. Units MHz Ω pF uW Fundamental, Parallel Resonant
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Micrel, Inc.
SM843031-01
Figure 1. Duty Cycle Timing
Figure 2. All Outputs Rise/Fall Time
Figure 3. RMS Phase Noise/Jitter
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Micrel, Inc.
SM843031-01
Figure 4. LVPECL Output Load and Test Circuit
Figure 5. Crystal Input Interface
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M9999-100110-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SM843031-01
Package Information
8-Pin TSSOP (K-8)
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. © 2010 Micrel, Incorporated.
October 2010
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