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SM840001
106.25MHz Ultra-Low Jitter Clock Synthesizer
General Description
The SM840001 synthesizer series were designed for Fibre Channel applications. The device design is optimized for 106.25MHz or 212.5MHz using a 26.5625MHz fundamental parallel resonant crystal, with stability and accuracy over the full operating range. The SM840001 includes a unique power reduction methodology, along with a patented RotaryWaveTM architecture, that provides a stable clock with very low noise for optimized performance. This yields an overall improved Bit Error Rate (BER) and improved waveform integrity. Datasheets and support documentation can be found on Micrel's web site at: www.micrel.com.
Features
* Generates a single LVCMOS/LVTTL output * Integrated loop filter components * RMS Phase Jitter: - 510 fs (typ) at 106.25MHz - 320 fs (typ) at 212.50MHz * Operates with either a 3.3V or 2.5V supply * Power consumption is <77mA @ 3.3 V * Fundamental crystal oscillator interface * Input frequency of 26.5625 MHz parallel resonant * Selectable output frequency: 106.25MHz or 212.5MHz * Temperature range: -40C to +75C * Available in 8-pin TSSOP package
Applications
* Fibre Channel * Storage ___________________________________________________________________________________________________________
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
March 2010
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Micrel, Inc.
SM840001
Ordering Information(1)
Part Number SM840001KA SM840001KA TR
Note: 1. Devices are Green, RoHS-compliant and PFOS-compliant. 2. Tape and Reel.
(2)
Package Type K-8 K-8
Operating Range -40C to +75C -40C to +75C
Package Marking 840001 840001
Lead Finish NiPdAu NiPdAu
Pin Configuration
8-Pin TSSOP (K-8)
Pin Description
Pin Number 1 2 3 4 5 6 7 8 Pin Name VDDA OE XTAL OUT XTAL IN FSEL GND Q0 VDD Type P I O I I P O P Pull-down Pull-up Level Pin Function Analog Power. Output Enable: 1 = Enable, 0 = Disable. Crystal Out. Crystal Input. Frequency Select Pin. Ground. Single Ended LVCMOS Clock Out. Core Power.
Frequency Select Table
FSEL 0 1 Output (MHz) 106.25 (Default) 212.5
Output Enable
OE 0 1 Output Disable Enable
March 2010
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Micrel, Inc.
SM840001
Absolute Maximum Ratings(1)
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.)....................... 260C Storage Temperature (Ts) .........................-65C to +150C
Operating Ratings(2)
Supply Voltage (VIN)............................. +2.375V to +3.465V Ambient Temperature (TA) .......................... -40C to +75C Junction Thermal Resistance TSSOP (JA).....................................................150C/W
DC Electrical Characteristics
VDD = 2.5V 5%; TA = -40C to +75C, unless noted.
Symbol VDD VDDA IDD IDDA Parameter Core Supply Voltage Analog Supply Voltage Core Supply Current Analog Supply Current No load Condition Min 2.375 2.375 Typ 2.50 2.50 12 48 Max 2.625 2.625 20 55 Units V V mA mA
DC Electrical Characteristics
VDD = 3.3V 5%; TA = -40C to +75C, unless noted.
Symbol VDD VDDA IDD IDDA Parameter Core Supply Voltage Analog Supply Voltage Core Supply Current Analog Supply Current No load Condition Min 3.135 3.135 Typ 3.30 3.30 15 49 Max 3.465 3.465 22 55 Units V V mA mA
LVCMOS DC Characteristics
VDD = 2.5V and 3.3V 5%; TA = -40C to +75C, unless noted.
Symbol VIH VIL VOH VOL IIH IIL IIH IIL
Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating.
Parameter Input HIGH Voltage Input LOW Voltage Output HIGH Voltage Output LOW Voltage Input HIGH Current Input LOW Current Input HIGH Current Input LOW Current
Condition VDD = 3.3V 5% VDD = 2.5V 5% VDD = 3.3V 5% VDD = 2.5V 5% VDD = 3.3V 5% VDD = 2.5V 5% Output Enable input Output Enable input FSEL input FSEL input
Min 2 1.7 -0.30 -0.30 2.6 1.8
Typ
Max VDD +0.3 VDD + 0.3 0.80 0.70
Units V V V V V V
0.5 5 -150 150 -5
V A A A A
March 2010
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Micrel, Inc.
SM840001
AC Electrical Characteristics
VDD = 2.5V and 3.3V 5%; TA = -40C to +75C, unless noted.
Symbol FOUT Parameter Output Frequency Condition FSEL=1 FSEL=0 106.25MHz, tJITTER RMS Phase Jitter Integration Range: 637kHz to 10MHz 212.50MHz Integration Range: 2.55MHz to 20MHz t R / tF ODC Output Rise/Fall Time Output Duty Cycle 20% to 80% 106.25MHz 212.50MHz 100 48 45 Min 186.66 93.33 Typ 212.5 106.25 510 320 350 52 55 Max 226.66 113.33 Units MHz MHz fs fs ps % %
3.3V Carrier Frequency, 106.25MHz
Offset from Carrier 100Hz 1kHz 10kHz 100kHz 1MHz 10MHz 40MHz Measured Phase Noise -97 -122 -131 -126 -144 -163 -165 Unit dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz
3.3V Carrier Frequency, 212.5MHz
Offset from Carrier 100Hz 1kHz 10kHz 100kHz 1MHz 10MHz 40MHz Measured Phase Noise -92 -116 -124 -120 -138 -161 -163 Unit dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz
Crystal Characteristics
Parameter Mode of Oscillation Frequency Equivalent Series Resistance (ESR) Shunt Capacitor Drive Level Condition Min Typ 26.5625 50 7 1 Max Units MHz pF mW Fundamental Parallel Resonant
March 2010
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Micrel, Inc.
SM840001
Functional Description
The SM840001 provides a high performance and high accuracy solution for a precision clock source at 106.25 or 212.50MHz derived from a low cost 26.5625MHz Xtal. A single 12mA LVCMOS output is provided with tri state capability, controlled via an external pin (OE). The design of the SM840001 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 integer divide ratios. Output Divider ratios are fixed at either /15 or /30 controlled via the FSEL pin, and the feedback divider also fixed at /120. Duty Cycle is inherently improved and guarantees tight control and stability on this critical specification. The provides improved specifications for Duty Cycle, Jitter, Phase Noise, Power Consumption, and noise sensitivity. Additionally, the SM840001 will operate at either 3.3V or 2.5V supplies.
Switching Waveforms
RMS Phase Noise/Jitter
Phase Noise Plot: 106.25MHz @ 3.3V
Phase Noise Plot: 212.5MHz @ 3.3V
March 2010
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Micrel, Inc. Power Supply Filtering The SM840001 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
SM840001
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 of the crystal must be considered in order to calculate 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.)
Equivalent Series Resistance (ESR) Max. 50 Cut Load Cap. 18pF Shunt Cap. Max. 7pF Drive Max. 0.1m W
Figure 2.
AT
Crystal Input Interface
March 2010
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Micrel, Inc. Total capacitance seen by crystal = CL = 1 1 (Ct1 + Cb1 + Cd1) + 1 (Ct2 + Cb2 + Cd2)
SM840001 Example: CL = 18pF, Cb = 2pF, Cd = 4pF Trim Cap = Ct = 2 (18pF) - (2pF +4pF) = 30pF The SM843022 has been characterized with 25MHz, 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.
Board Layout
March 2010
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M9999-031810-B hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SM840001
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
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. (c) 2010 Micrel, Incorporated.
March 2010
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M9999-031810-B hbwhelp@micrel.com or (408) 955-1690

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