19-4997; Rev 2; 10/09 Spread-Spectrum Crystal Multiplier The DS1080L is a low-jitter, crystal-based clock generator with an integrated phase-locked loop (PLL) to generate spread-spectrum clock outputs from 16MHz to 134MHz. The device is pin-programmable to select the clock multiplier rate as well as the dither magnitude. The DS1080L has a spread-spectrum disable mode and a power-down mode to conserve power. Applications Automotive Features ♦ Generates Spread-Spectrum Clocks from 16MHz to 134MHz ♦ Selectable Clock Multiplier Rates of 1x, 2x, and 4x ♦ Center Spread-Spectrum Dithering ♦ Selectable Spread-Spectrum Modulation Magnitudes of ±0.5%, ±1.0%, and ±1.5% ♦ Spread-Spectrum Disable Mode ♦ Low Cycle-to-Cycle Jitter Cable Modems ♦ Power-Down Mode with High-Impedance Output Cell Phones ♦ Low Cost Computer Peripherals ♦ Low Power Consumption Copiers ♦ 3.0V to 3.6V Single-Supply Operation Infotainment ♦ -40°C to +125°C Temperature Operation PCs ♦ Small 8-Lead µSOP Package Printers Ordering Information Pin Configuration PART DS1080LU+ TOP VIEW TEMP RANGE PIN-PACKAGE -40°C to +125°C 8 μSOP +Denotes a lead(Pb)-free/RoHS-compliant package. + X1 1 GND 2 CMSEL 8 X2 7 VCC 3 6 SSO SMSEL 4 5 PDN DS1080L μSOP ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 DS1080L General Description DS1080L Spread-Spectrum Crystal Multiplier ABSOLUTE MAXIMUM RATINGS Voltage on VCC Relative to GND .........................-0.5V to +3.63V Voltage on Any Lead Relative to GND ...............-0.5V to (VCC + 0.5V), not to exceed +3.63V Operating Temperature Range .........................-40°C to +125°C Storage Temperature Range .............................-55°C to +125°C Soldering Temperature...................See J-STD-020 Specification Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. RECOMMENDED OPERATING CONDITIONS (TA = -40°C to +125°C) PARAMETER SYMBOL MAX UNITS 3.0 3.6 V VIH 0.8 x VCC VCC + 0.3 V VIL GND 0.3 0.2 x VCC V Supply Voltage VCC Input Logic 1 Input Logic 0 CONDITIONS (Note 1) MIN TYP Input Logic Float IIF 0v < VIN < VCC (Note 2) ±1 μA Input Leakage IIL 0V < VIN < VCC (Note 3) ±80 μA SSO Load Crystal or Clock Input Frequency CSSO 15 67MHz ≤ SSO < 101MHz 10 101MHz ≤ SSO < 134MHz 7 16.0 fIN Crystal ESR XESR Clock Input Duty Cycle FINDC Crystal Parallel Load Capacitance SSO < 67MHz CL 33.4 40 (Note 4) pF MHz 90 Ω 60 % 18 pF MAX UNITS DC ELECTRICAL CHARACTERISTICS (VCC = +3.0V to +3.6V, TA = -40°C to +125°C.) PARAMETER SYMBOL CONDITIONS MIN TYP Supply Current ICC1 CSSO = 15pF, SSO = 16MHz 13 mA Power-Down Current ICCQ PDN = GND, all input pins floating 200 μA +1 μA 0.4 V Output Leakage (SSO) IOZ PDN = GND Low-Level Output Voltage (SSO) VOL IOL = 4mA High-Level Output Voltage (SSO) VOH IOH = -4mA Input Capacitance (X1/X2) CIN (Note 5) 2 -1 2.4 V 5 _______________________________________________________________________________________ pF Spread-Spectrum Crystal Multiplier DS1080L AC ELECTRICAL CHARACTERISTICS (VCC = +3.0 to +3.6V, TA = -40°C to +125°C.) PARAMETER SSO Duty Cycle SYMBOL SSODC Rise Time tR Fall Time Peak Cycle-to-Cycle Jitter CONDITIONS Measured at VCC/2 40 MAX 60 UNITS % 1.6 ns tF (Note 6) 1.6 ns tJ f SSO = 16MHz, TA = -40 to +85°C, 10,000 cycles (Note 5) 75 ps t POR PDN pin (Note 7) Power-Down Time t PDN PDN pin (Notes 8 and 9) Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8: Note 9: TYP (Note 6) Power-Up Time Dither Rate MIN fDITHER 16MHz 20 33.4MHz 11 100 ms ns f IN / 1024 All voltages referenced to ground. Maximum source/sink current applied to input to be considered a float. Applicable to pins CMSEL, SMSEL, and PDN. See information about CL1 and CL2 in the Applications Information section at the end of the data sheet. Not production tested. For 7pF load. Time between PDN deasserted to output active. Time between PDN asserted to output high impedance. Guaranteed by design. _______________________________________________________________________________________ 3 Typical Operating Characteristics (VCC = 3.3V, TA = +25°C, unless otherwise noted.) 8 CMSEL = 2x AT 16MHz 6 CMSEL = 1x AT 16MHz 4 8 CMSEL = 1x AT 16MHz CMSEL = 2x AT 16MHz 4 AT 16MHz 2 0 12 10 8 6 CMSEL = 1x AT 16MHz CMSEL = 2x AT 16MHz 2 0 0 3.05 3.15 3.25 3.35 3.45 3.55 3.65 -40 10 SUPPLY VOLTAGE (V) 60 60 DS1080L toc04 0.20 56 DUTY CYCLE (%) 0.10 54 52 50 48 46 CMSEL = 1x AT 16MHz CMSEL = 2x AT 16MHz 0.05 AT 16MHz 58 CMSEL = 4x AT 16MHz 0.15 31 DUTY CYCLE vs. TEMPERATURE PDN SUPPLY CURRENT vs. TEMPERATURE AT 16MHz 26 FREQUENCY (MHz) TEMPERATURE (°C) 0.25 PDN SUPPLY CURRENT (mA) 21 16 110 DS1080L toc05 2.95 CMSEL = 4x AT 16MHz 14 4 2 44 42 40 0 -40 10 60 10 60 110 TEMPERATURE (°C) DUTY CYCLE vs. SUPPLY VOLTAGE OUTPUT DURING POWER-UP AND POWER-DOWN DS1080L toc06 DS1080L toc07 TEMPERATURE (°C) AT 16MHz 56 POWERDOWN 54 SSO AND PDN DUTY CYCLE (%) -40 110 60 58 52 50 48 POWERUP tPDN tPOR 46 44 42 40 2.95 3.05 3.15 3.25 3.35 3.45 3.55 3.65 TIME (μs) SUPPLY VOLTAGE (V) 4 DS1080L toc03 CMSEL = 4x AT 16MHz 6 16 DS1080L toc02 AT 16MHz 10 SUPPLY CURRENT (mA) CMSEL = 4x AT 16MHz DS1080L toc01 AT 16MHz 10 SUPPLY CURRENT vs. FREQUENCY SUPPLY CURRENT vs. TEMPERATURE 12 SUPPLY CURRENT (mA) SUPPLY CURRENT vs. SUPPLY VOLTAGE 12 SUPPLY CURRENT (mA) DS1080L Spread-Spectrum Crystal Multiplier _______________________________________________________________________________________ Spread-Spectrum Crystal Multiplier PIN NAME 1 X1 2 GND 3 4 FUNCTION Crystal Drive/Clock Input. A crystal with the proper loading capacitors is connected across X1 and X2. Instead of a crystal, a clock can be applied at the X1 input. Signal Ground CMSEL Clock Multiplier Select. Tri-level digital input. 0 = 1x Float = 2x 1 = 4x SMSEL Spread-Spectrum Magnitude Select. Tri-level digital input. 0 = ±0.5% Float = ±1.0% 1 = ±1.5% 5 PDN Power-Down/Spread-Spectrum Disable. Tri-level digital input. 0 = Power-Down/SSO Three-Stated Float = Power-Up/Spread Spectrum Disabled 1 = Power-Up/Spread Spectrum Enabled 6 SSO Spread-Spectrum Clock Multiplier Output. Outputs a 1x, 2x, or 4x spread-spectrum version of the crystal or clock applied at the X1/X2 pins. 7 VCC Supply Voltage 8 X2 Crystal Drive Output. A crystal with the proper loading capacitors is connected across X1 and X2. If a clock is connected to X1, then X2 should be left open circuit. Block Diagram VCC X1 16MHz TO 33.4MHz X2 CL1 VCC fIN CRYSTAL OSCILLATOR 1x/2x/4x CLOCK MULTIPLYING PLL WITH SPREAD SPECTRUM SSO fSSO fSSO = 16MHz TO 134MHz CL2 PDN CMSEL SMSEL GND CONFIGURATION DECODE AND CONTROL DS1080L NOTE: SEE INFORMATION ABOUT CL1 AND CL2 IN THE APPLICATIONS INFORMATION SECTION AT THE END OF THE DATA SHEET. _______________________________________________________________________________________ 5 DS1080L Pin Description Detailed Description The DS1080L is a crystal multiplier with center spreadspectrum capability. A 16MHz to 33.4MHz crystal is connected to the X1 and X2 pins. Alternately, a 16MHz to 33.4MHz clock can be applied to X1 in place of the crystal. In such applications, X2 would be left open circuit. Using the CMSEL input, the user selects whether the attached crystal or input clock is multiplied by 1, 2, or 4. The DS1080L is capable of generating spreadspectrum clocks from 16MHz to 134MHz. The PLL can dither the output clock about its center frequency at a user-selectable magnitude. Using the SMSEL input, the user selects the dither magnitude. The PDN input can be used to place the device into a low-power standby mode where the SSO output is tristated. If the PDN pin is floated, the SSO output is active but the spread-spectrum dithering is disabled. The spread-spectrum dither rate is fixed at fIN / 1024 to keep the dither rate above the audio frequency range. On power-up, the output clock (SSO) remains threestated until the PLL reaches a stable frequency (fSSO) and dither (fDITHER). Applications Information Crystal Selection The DS1080L requires a parallel resonating crystal operating in the fundamental mode, with an ESR of less than 90Ω. The crystal should be placed very close to the device to minimize excessive loading due to parasitic capacitances. Oscillator Input When driving the DS1080L using an external oscillator clock, consider the input (X1) to be high impedance. Crystal Capacitor Selection The load capacitors CL1 and CL2 are selected based on the crystal specifications (from the data sheet of the crystal used). The crystal parallel load capacitance is calculated as follows: CL = CL1 x CL2 + CIN CL1 + CL2 CL = CLX + CIN 2 Equation 2 where CL1 = CL2 = CLX. Equation 2 is used to calculate the values of CL1 and CL2 based on values on CL and CIN noted in the data sheet electrical specifications. Power-Supply Decoupling To achieve best results, it is highly recommended that a decoupling capacitor is used on the IC power-supply pins. Typical values of decoupling capacitors are 0.001μF and 0.1μF. Use a high-quality, ceramic, surface-mount capacitor, and mount it as close as possible to the VCC and GND pins of the IC to minimize lead inductance. +1.5% +1.0% +0.5% f0 -0.5% -1.0% -1.5% t Figure 1. Spread-Spectrum Frequency Modulation 6 Equation1 For the DS1080L use CL1 = CL2 = CLX. In this case, the equation then reduces to: DITHER CYCLE RATE = fDITHER = fIN/1024 fSSO DS1080L Spread-Spectrum Crystal Multiplier _______________________________________________________________________________________ Spread-Spectrum Crystal Multiplier CRYSTAL CL1 CL2 X1 GND CMSEL SMSEL 8 1 2 DS1080L 7 3 6 4 5 X2 VCC VCC DECOUPLING CAPACITOR SSO PDN fSSO VCC NOTE: IN THE ABOVE CONFIGURATION WITH PDN CONNECTED TO VCC, SMSEL CONNECTED TO GND AND CMSEL FLOATING, THE DEVICE IS IN NORMAL OPERATION WITH 2x CLOCK MULTIPLICATION, AND SPREAD-SPECTRUM MAGNITUDE OF ±0.5%. Package Information Layout Considerations As noted earlier, the crystal should be placed very close to the device to minimize excessive loading due to parasitic capacitances. Care should also be taken to minimize loading on pins that could be floated as a programming option (SMSEL and CMSEL). Coupling on inputs due to clocks should be minimized. Chip Information TRANSISTOR COUNT: 3951 SUBSTRATE CONNECTED TO GROUND For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 8 μSOP U8+1 21-0036 _______________________________________________________________________________________ 7 DS1080L Typical Operating Circuit DS1080L Spread-Spectrum Crystal Multiplier Revision History REVISION NUMBER REVISION DATE 0 11/05 1 3/06 2 10/09 DESCRIPTION PAGES CHANGED Initial release. — Changed VIHMIN from 0.7V x VCC to 0.08V x VCC and VILMAX from 0.3 x VCC to 0.2V x VCC in the Recommended Operating Conditions table. 2 Changed the part number in the Ordering Information table. 1 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.