SM840004-11 62.5/125MHz Gigabit Ethernet, 4 Output, Ultra-Low Jitter Clock Synthesizer General Description Features The SM840004-11 clock synthesizer was designed for • Generates 4 optimized LVCMOS clock outputs Gigabit Ethernet applications. The device design is • RMS phase jitter @ 125MHz: ~55 fs (typ) optimized for 62.5MHz and 125MHz using a standard • Integrated loop filter components 25MHz fundamental parallel resonant crystal, with • Operates with either a 3.3V or 2.5V supply unparalleled stability and accuracy over the full operating • Power consumption 65mA (typ @ 2.5V) range, and provides an easy fit for Jitter and Phase Noise standards for these high performance interfaces. • Selectable output frequency: 125MHz or 62.5MHz The SM840004-11 design includes a unique power • Input frequency of 25MHz reduction methodology, along with a patented • Fundamental parallel resonant crystal interface RotaryWave™ architecture, that provides a stable clock • Pin compatible with the ICS/IDT840004-11 with very low noise for optimized performance. This yields • Industrial temperature range: –40°C to +85°C an overall improved Bit Error Rate (BER) and improved waveform integrity. • Green, RoHS-compliant and PFOS-compliant Datasheets and support documentation can be found on Micrel’s web site at: www.micrel.com. ___________________________________________________________________________________________________________ Block Diagram RotaryWave is a 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 July 2010 M9999-070110-A [email protected] or (408) 955-1690 Micrel, Inc. SM840004-11 Ordering Information(1) Package Type Operating Range Package Marking SM840004-11KA K-20 Industrial 840004-11 SM840004-11KA TR K-20 Industrial 840004-11 Part Number Note: 1. Devices are Green, RoHS-compliant and PFOS-compliant. Pin Configuration 20-Pin TSSOP (K-20) Pin Description Pin Number Pin Name Type Level Pin Function 1 F_SEL I Pull-up Frequency Select Pin. 2,3,4,6,7,9,20 NC 5 OE I NC Pull-up No Connect. Do Not Use. Output Enable: (1=Active, 0=High-Z) 8 VDDA P Analog Power. 10 VDD P Core Power. 11 XTAL_OUT O Crystal Out. 12 XTAL_IN I Crystal In. 13,19 GND P Ground. 14 Q3 O Single Ended LVCMOS Clock Out-3. 15 Q2 O Single Ended LVCMOS Clock Out-2. 16 VDDO P Output Power Supply. 17 Q1 O Single Ended LVCMOS Clock Out-1. 18 Q0 O Single Ended LVCMOS Clock Out-0. Configuration Table F_SEL M/N Ratio M Divider N Divider Output Frequency (MHz) 0 2.5 130 52 62.5 1 5 130 26 125 July 2010 2 M9999-070110-A [email protected] or (408) 955-1690 Micrel, Inc. SM840004-11 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VDD)...................................................+4.6V Input Voltage (VIN) ................................ –0.50V to VDD+0.5V Output Voltage (VOUT) .......................... –0.50V to VDD+0.5V Lead Temperature (soldering, 20sec.)....................... 260°C Storage Temperature (Ts) .........................–65°C to +150°C Supply Voltage (VIN)............................. +2.375V to +3.465V Ambient Temperature (TA) .......................... –40°C to +85°C Junction Thermal Resistance TSSOP (θJA).....................................................113°C/W DC Electrical Characteristics VDD = 2.5V ±5%; TA = –40°C to +85°C, unless noted. Min Typ Max Units VDD Symbol Core Supply Voltage Parameter Condition 2.375 2.50 2.625 V VDDA Analog Supply Voltage 2.375 2.50 2.625 V VDDO Output Supply Voltage 2.375 2.50 2.625 V IDD Power Supply Current 0.1 1 mA IDDA Analog Supply Current 50 60 mA IDD0 Output Supply Current 15 23 mA Min Typ Max Units No Load DC Electrical Characteristics VDD = 3.3V ±5%; TA = –40°C to +85°C, unless noted. Symbol Parameter Condition VDD Core Supply Voltage 3.135 3.30 3.465 V VDDA Analog Supply Voltage 3.135 3.30 3.465 V VDDO Output Supply Voltage 3.135 3.30 3.465 V IDD Power Supply Current 0.1 1 mA IDDA Analog Supply Current 50 60 mA IDDO Output Supply Current 25 32 mA No Load LVCMOS DC Electrical Characteristics TA = –40°C to +85°C, unless noted. Symbol Parameter VIH Input HIGH Voltage VIL Input LOW Voltage VOH Output HIGH Voltage Max Units VDD = 3.3V ±5% Condition 2 VDD +0.3 V VDD = 2.5V ±5% 1.7 VDD + 0.3 V VDD = 3.3V ±5% -0.30 0.80 V VDD = 2.5V ±5% -0.30 0.70 V VDD = 3.3V ±5% 2.6 V VDD = 2.5V ±5% 1.8 V VOL Output LOW Voltage IIH Input HIGH Current Output Enable input IIL Input LOW Current Output Enable input IIH Input HIGH Current FSEL input IIL Input LOW Current FSEL input Min Typ 0.5 V 5 µA -150 µA 150 -5 µA µA Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. July 2010 3 M9999-070110-A [email protected] or (408) 955-1690 Micrel, Inc. SM840004-11 AC Electrical Characteristics VDD = 2.5V and 3.3V ±5%; TA = –40°C to +85°C, unless noted. Symbol Parameter Condition Min Typ FOUT Output Frequency tSKEW Output to Output Skew tJITTER RMS Phase Jitter(random) 62.5MHz @ 1.875MHz-20MHz 356 fs t R / tF Output Rise/Fall Time 20% to 80% 300 ps ODC Output Duty Cycle 62.5MHz & 125MHz F_SEL = 1 125 F_SEL = 0 62.5 Max MHz 12 125MHz @ 1.875MHz-20MHz 55 48 50 Units ps fs 52 % Test Circuit 3.3V Output Load AC Test Circuit 3.3V Carrier Frequency, 62.5MHz Offset from Carrier Measured Phase Noise 3.3V Carrier Frequency, 125MHz Unit Offset from Carrier Measured Phase Noise Unit 100Hz -103 dBc/Hz 100Hz -103 dBc/Hz 1kHz -124 dBc/Hz 1kHz -125 dBc/Hz 10kHz -137 dBc/Hz 10kHz -134 dBc/Hz 100kHz -135 dBc/Hz 100kHz -132 dBc/Hz 1MHz -145 dBc/Hz 1MHz -143 dBc/Hz 1.825MHz -151 dBc/Hz 1.825 -152 dBc/Hz 10MHz -169 dBc/Hz 10MHz -166 dBc/Hz 20MHz -169 dBc/Hz 20MHz -167 dBc/Hz July 2010 4 M9999-070110-A [email protected] or (408) 955-1690 Micrel, Inc. SM840004-11 Crystal Characteristics Parameter Min Mode of Oscillation Fundamental Parallel Resonant Typ Frequency Max 25 Units MHz Equivalent Series Resistance (ESR) 50 Ω Shunt Capacitor 7 pF Drive Level 1 mW Functional Description The SM840004-11 provides a high performance and high accuracy solution for a precision clock source at either 62.5MHz or 125MHz derived from a low cost 25MHz Xtal. Four synchronous low skew 12mA capable LVCMOS outputs are provided with tri state controlled via an external pin (OE). The design of the SM840004-11 consumes very low power in the PLL due to a patented technology in the VCO and the associated dividers. The VCO range is ~3.2GHz to 3.5GHz providing high resolution and easy July 2010 integer divide ratios. Output divider ratios are fixed at either ÷26 or ÷52 via the F_SEL pin, and the feedback divider is fixed at ÷130. Duty Cycle is inherently improved and provides tight control and stability on this critical specification. This provides improved specifications for Duty Cycle, Jitter, Phase Noise, Power Consumption, and noise sensitivity. Additionally, the SM840004-11 will operate at either 3.3V or 2.5V supplies. 5 M9999-070110-A [email protected] or (408) 955-1690 Micrel, Inc. SM840004-11 RMS Phase Noise/Jitter Phase Noise Plot 125MHz @ 3.3V July 2010 6 M9999-070110-A [email protected] or (408) 955-1690 Micrel, Inc. SM840004-11 Switching Waveforms Output Rise/Fall Time Output-Output Skew July 2010 7 M9999-070110-A [email protected] or (408) 955-1690 Micrel, Inc. SM840004-11 Power Supply Filtering The SM840004-11 provides separate power supply pins to isolate any high switching noise from outputs to internal core blocks. VDD and VDDA should be individually connected to the power plane through vias. Bypass capacitors should be used for each pin. Figure 2, illustrates how the power supply filter for 3.3V and 2.5V is configured. Crystal Loading Crystal Recommendations This device requires a parallel resonance crystal. Substituting a series resonance crystal will cause this device to operate at the wrong frequency and violate the ppm specifications. To achieve low ppm error, the total capacitance the crystal will see must be considered to calculate the appropriate capacitive loading (CL). Load Capacitance at each side: Trim Capacitance = Ct = (2*CL-(Cb + Cd)) CL: Crystal load capacitance. Defined by manufacturer Ct: External trim capacitors. (Trimmed CL Load capacitance to get the right ppm) Cb: Board capacitance (vias, traces, etc.) Cd: Internal capacitance of the device (lead frame, bond wires, pin, etc.) Figure 2. Power Supply Filter Equivalent Series Resistance (ESR) Max. Cut Load Cap. Shunt Cap. Max. Drive Max. 50Ω AT 18pF 7pF 0.1mW Crystal Input Interface July 2010 8 M9999-070110-A [email protected] or (408) 955-1690 Micrel, Inc. SM840004-11 Total capacitance seen by crystal = CL = 1 1 (Ct1 + Cb1 + Cd1) July 2010 + 1 (Ct2 + Cb2 + Cd2) Example: CL = 18pF, Cb = 2pF, Cd = 4pF Trim Cap = Ct = 2 (18pF) - (2pF +4pF) = 30pF The SM840004-11has been characterized with 19.44MHz, 18pF parallel resonant crystal. The trim capacitors Ct1 and Ct2 were optimized to minimize the ppm error. To minimize the board capacitance, a short trace from pin to crystal footprint without vias is desirable. It is preferable to have ground shielding or distance between the crystal traces and noisy signals on the board. 9 M9999-070110-A [email protected] or (408) 955-1690 Micrel, Inc. SM840004-11 Package Information 20-Pin TSSOP (K-20) 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 The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. 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. July 2010 10 M9999-070110-A [email protected] or (408) 955-1690