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Technical content
Features
Generates one LVPECL cl ock outputs at 156.25MHz 2.5V or 3.3V operating range Typical phase jitter @ 156.25MHz (1.875MHz to 20MHz): 110fs Industrial temperature range Green, RoHS-, and PFOS- compliant Available in 24-pin 4mm 4mm QFN package
Applications
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Micrel, Inc. SM802121 January 2012 2 M9999-011212-A hbwhelp@micrel.com or (408) 955-1690 Ordering Information(1) Part Number Marking Shipping Temperature Range Package SM802121UMG 802121 Tube 40C to +85C 24-Pin QFN SM802121UMGTR 802121 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)
Micrel, Inc. SM802121 January 2012 3 M9999-011212-A hbwhelp@micrel.com or (408) 955-1690 Pin Description Pin Number Pin Name Pin Type Pin Level Pin Function 16, 17 /Q, Q O, (DIF) LVPECL Differential Clock Output 156.25MHz. 1, 18 VDDO PWR Power Supply for Output. 2, 22 VSSO PWR Power Supply Ground for Output.
6 XTAL_SEL I, (SE) LVCMOS Selects PLL Input Reference Source (0 = REF_IN, 1 =
XTAL, 45KΩ pull-up). 3, 4, 20, 21, 23, 24 NC No Connect. Do not connect anything to these pins. 5, 7, 12, 15, 19 TEST Factory Test Pi ns. Do not connect anything to these pins. 8 VDD PWR Core Power Supply. 13, 14 VSS (Exposed Pad) PWR Core Power Supply Ground. The exposed pad must be connected to the VSS ground plane. 9 REF_IN I, (SE) LVCMOS Reference Clock Input. 10 XIN I, (SE) crystal Crystal Reference Input. No load caps needed. (See Fig. 5) 11 XOUT O, (SE) crystal Crystal Reference Output. No load caps needed. (See Fig. 5)
Application Information
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 and do not place switching signals or noisy supplies under the crystal. Crystal load capacitance is built inside the die so no external capacitance is needed. See the Selecting a quartz crystal for the Clockworks Flex I Family of Precision Synthesizers application note for further details. Contact Micrel’s HBW applications group if you need assistance on selecting a suitable crystal for your application at hbwhelp@micrel.com Truth Table XTAL_SEL INPUT
0 REF_IN
1 XTAL
Micrel, Inc. SM802121 January 2012 4 M9999-011212-A hbwhelp@micrel.com or (408) 955-1690 Absolute Maximum Ratings(1) Operating Ratings(2) Junction Thermal Resistance(3) QFN ( JA) QFN (JB) VDD = VDDO = 3.3V 5% or 2.5V 5% VDD = 3.3V 5%, VDDO= 3.3V 5% or 2.5V 5% TA = 40C to 85C. Symbol Parameter Condition Min. Typ. Max. Units VDD, VDDO 2.5V Operating Voltage 2.375 2.5 2.625 V VDD, VDDO 3.3V Operating Voltage 3.135 3.3 3.465 V IDD Supply Current V DD + VDDO XTAL_SEL = 0; REF_IN source, outputs open 78 100 mA IDD Supply Current V DD + VDDO XTAL_SEL = 1; CRYSTAL source, outputs open 88 114 mA VDD = VDDO= 3.3V 5% or 2.5V 5% VDD = 3.3V 5%, VDDO = 3.3V 5% or 2.5V 5% TA = 40C to 85C. RL = 50Ω to VDDO 2V Symbol Parameter Condition Min. Typ. Max. Units VOH Output High Voltage VDDO 1.145 V DDO 0.97 V DDO 0.845 V VOL Output Low Voltage VDDO 1.945 V DDO 1.77 V DDO 1.645 V VSWING Output Voltage Swing 0.6 0.8 1.0 V 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. 2. The data sheet limits are not guaranteed if t he device is operated beyond the operating ratings. 3. Package thermal resistance assumes exposed pad is soldered (o r 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.
Micrel, Inc. SM802121 January 2012 5 M9999-011212-A hbwhelp@micrel.com or (408) 955-1690 LVCMOS (XTAL_SEL) DC Electrical Characteristics(4) VDD = 3.3V 5%, or 2.5V 5%, TA = 40C to 85C. Symbol Parameter Condition Min. Typ. Max. Units VIH Input High Voltage 2 V DD + 0.3 V VIL Input Low Voltage 0.3 0.8 V IIH Input High Current V DD = VIN = 3.465V 5 A IIL Input Low Current V DD = 3.465V, VIN = 0V 150 A REF_IN DC Electrical Characteristics(4) VDD = 3.3V 5%, or 2.5V 5%, TA = 40C to 85C. Symbol Parameter Condition Min. Typ. Max. Units VIH Input High Voltage 1.1 V DD + 0.3 V VIL Input Low Voltage 0.3 0.6 V XTAL_SEL = VIL, VIN = 0V to VDD 5 5 A IIN Input Current XTAL_SEL = VIH, VIN = VDD 20 µA Crystal Characteristics Parameter Condition Min. Typ. Max. Units Mode of Oscillation 10pF Load Fundamental, Parallel Resonant Frequency 25 MHz Equivalent Series Resistance (ESR) 50 Ω Shunt Capacitor (C0) 1 5 pF Correlation Drive Level 10 100 uW
Micrel, Inc. SM802121 January 2012 6 M9999-011212-A hbwhelp@micrel.com or (408) 955-1690 VDD = VDDO = 3.3V 5% or 2.5V 5% VDD = 3.3V 5%, VDDO= 3.3V 5% or 2.5V 5% TA = 40C to 85C. RL = 50Ω to VDDO 2V Symbol Parameter Condition Min. Typ. Max. Units FOUT Output Frequency 156.25 MHz FREF Reference Input Frequency 25 MHz TR/TF LVPECL Output Rise/Fall Time 20% 80% 80 175 350 ps ODC Output Duty Cycle 48 50 52 % TLOCK PLL Lock Time 20 ms Tjit() RMS Phase Jitter(6) 156.25MHz Integration Range (1.875MHz 20MHz) Integration Range (12kHz 20MHz) 110 250 fs Spurious Noise Components 6.25MHz 75 dBc Notes: 5. All phase-noise measurements were taken with an Agilent 5052B phase-noise system. 6. Measured using a 25MHz crystal as the input reference source. If using an external reference input, use a low phase noise source. With an external reference, the phase noise will follow the input source phase noise up to about 1MHz offset.
Micrel, Inc. SM802121 January 2012 7 M9999-011212-A hbwhelp@micrel.com or (408) 955-1690 Phase Noise Plots (XTAL Source) Phase Noise Plot: 156.25MHz, 1.875MHz 20MHz 101fS Phase Noise Plot: 156.25MHz, 12kHz 20MHz 243fS
Micrel, Inc. SM802121 January 2012 10 M9999-011212-A hbwhelp@micrel.com or (408) 955-1690
Package Information
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. © 2012 Micrel, Incorporated.