CS2000-CP-CZZR

CS2000-CP Fractional-N Clock Synthesizer & Clock Multiplier Features Delta-Sigma Fractional-N Frequency Synthesis – Generates a Low Jitter 6 - 75 MHz Clock from an 8 - 75 MHz Reference Clock Clock Multiplier / Jitter Reduction – Generates a Low Jitter 6 - 75 MHz Clock from a Jittery or Intermittent 50 Hz to 30 MHz Clock Source Highly Accurate PLL Multiplication Factor – Maximum Error Less Than 1 PPM in HighResolution Mode ® / SPI™ Control Port I²C Configurable Auxiliary Output Flexible Sourcing of Reference Clock – External Oscillator or Clock Source – Supports Inexpensive Local Crystal Minimal Board Space Required – No External Analog Loop-filter Components General Description The CS2000-CP is an extremely versatile system clocking device that utilizes a programmable phase lock loop. The CS2000-CP is based on a hybrid analog-digital PLL architecture comprised of a unique combination of a Delta-Sigma Fractional-N Frequency Synthesizer and a Digital PLL. This architecture allows for both frequency synthesis/clock generation from a stable reference clock as well as generation of a lowjitter clock relative to an external noisy synchronization clock. The design is also unique in that it can generate low-jitter clocks relative to noisy external synchronization clocks at frequencies as low as 50 Hz. The CS2000-CP supports both I²C and SPI for full software control. The CS2000-CP is available in a 10-pin MSOP package in Commercial (-10°C to +70°C) grade. Customer development kits are also available for device evaluation. Please see “Ordering Information” on page 35 for complete details. 3.3 V Timing Reference Frequency Reference PLL Output Lock Indicator I²C/SPI Software Control I²C / SPI Auxiliary Output 8 MHz to 75 MHz Low-Jitter Timing Reference Fractional-N Frequency Synthesizer 6 to 75 MHz PLL Output Output to Input Clock Ratio N 50 Hz to 30 MHz Frequency Reference Digital PLL & Fractional N Logic Output to Input Clock Ratio Preliminary Product Information http://www.cirrus.com This document contains information for a new product. Cirrus Logic reserves the right to modify this product without notice. Copyright © Cirrus Logic, Inc. 2008 (All Rights Reserved) JUN '08 DS761PP1 CS2000-CP TABLE OF CONTENTS 1. PIN DESCRIPTION ................................................................................................................................. 5 2. TYPICAL CONNECTION DIAGRAM ..................................................................................................... 6 3. CHARACTERISTICS AND SPECIFICATIONS ...................................................................................... 7 RECOMMENDED OPERATING CONDITIONS .................................................................................... 7 ABSOLUTE MAXIMUM RATINGS ........................................................................................................ 7 DC ELECTRICAL CHARACTERISTICS ................................................................................................ 7 AC ELECTRICAL CHARACTERISTICS ................................................................................................ 8 CONTROL PORT SWITCHING CHARACTERISTICS- I²C FORMAT ................................................... 9 CONTROL PORT SWITCHING CHARACTERISTICS - SPI FORMAT ............................................... 10 4. ARCHITECTURE OVERVIEW ............................................................................................................. 11 4.1 Delta-Sigma Fractional-N Frequency Synthesizer ......................................................................... 11 4.2 Hybrid Analog-Digital Phase Locked Loop .................................................................................... 11 4.2.1 Fractional-N Source Selection for the Frequency Synthesizer .............................................. 12 5. APPLICATIONS ................................................................................................................................... 13 5.1 Timing Reference Clock Input ........................................................................................................ 13 5.1.1 Internal Timing Reference Clock Divider ............................................................................... 13 5.1.2 Crystal Connections (XTI and XTO) ...................................................................................... 13 5.1.3 External Reference Clock (REF_CLK) .................................................................................. 14 5.2 Frequency Reference Clock Input, CLK_IN ................................................................................... 14 5.2.1 CLK_IN Frequency Detector ................................................................................................. 14 5.2.2 CLK_IN Skipping Mode ......................................................................................................... 14 5.2.3 Adjusting the Minimum Loop Bandwidth for CLK_IN ............................................................ 16 5.3 Output to Input Frequency Ratio Configuration ............................................................................. 17 5.3.1 User Defined Ratio (RUD), Frequency Synthesizer Mode .................................................... 17 5.3.2 User Defined Ratio (RUD), Hybrid PLL Mode ....................................................................... 17 5.3.3 Manual Ratio Modifier (R-Mod) ............................................................................................. 18 5.3.4 Automatic Ratio Modifier (Auto R-Mod) - Hybrid PLL Mode Only ......................................... 18 5.3.5 Effective Ratio (REFF) .......................................................................................................... 19 5.3.6 Fractional-N Source Selection ............................................................................................... 20 5.3.7 Ratio Configuration Summary ............................................................................................... 21 5.4 PLL Clock Output ........................................................................................................................... 22 5.5 Auxiliary Output .............................................................................................................................. 22 5.6 Clock Output Stability Considerations ............................................................................................ 23 5.6.1 Output Switching ................................................................................................................... 23 5.6.2 PLL Unlock Conditions .......................................................................................................... 23 6. SPI / I²C CONTROL PORT ................................................................................................................... 24 6.1 SPI Control ..................................................................................................................................... 24 6.2 I²C Control ...................................................................................................................................... 24 6.3 Memory Address Pointer ............................................................................................................... 26 6.3.1 Map Auto Increment .............................................................................................................. 26 7. REGISTER QUICK REFERENCE ........................................................................................................ 26 8. REGISTER DESCRIPTIONS ................................................................................................................ 27 8.1 Device I.D. and Revision (Address 01h) ....................................................................................... 27 8.1.1 Device Identification (Device[4:0]) - Read Only ..................................................................... 27 8.1.2 Device Revision (Revision[2:0]) - Read Only ........................................................................ 27 8.2 Device Control (Address 02h) ........................................................................................................ 27 8.2.1 Unlock Indicator (Unlock) - Read Only .................................................................................. 27 8.2.2 PLL Input Sample Rate Indicator (FsDet[1:0]) - Read Only .................................................. 27 8.2.3 Auxiliary Output Disable (AuxOutDis) ................................................................................... 28 8.2.4 PLL Clock Output Disable (ClkOutDis) .................................................................................. 28 8.3 Device Configuration 1 (Address 03h) ........................................................................................... 28 8.3.1 R-Mod Selection (RModSel[2:0]) ........................................................................................... 28 2 DS761PP1 CS2000-CP 8.3.2 Ratio Selection (RSel[1:0]) .................................................................................................... 28 8.3.3 Auxiliary Output Source Selection (AuxOutSrc[1:0]) ............................................................. 29 8.3.4 Enable Device Configuration Registers 1 (EnDevCfg1) ........................................................ 29 8.4 Device Configuration 2 (Address 04h) ........................................................................................... 29 8.4.1 Auto R-Modifier Enable (AutoRMod) ..................................................................................... 29 8.4.2 Lock Clock Ratio (LockClk[1:0]) ............................................................................................ 29 8.4.3 Fractional-N Source for Frequency Synthesizer (FracNSrc) ................................................. 30 8.5 Global Configuration (Address 05h) ............................................................................................... 30 8.5.1 Device Configuration Freeze (Freeze) ................................................................................ 30 8.5.2 Enable Device Configuration Registers 2 (EnDevCfg2) ....................................................... 30 8.6 Ratio 0 - 3 (Address 06h - 15h) ...................................................................................................... 30 8.7 Function Configuration 1 (Address 16h) ........................................................................................ 31 8.7.1 Clock Skip Enable (ClkSkipEn) ............................................................................................. 31 8.7.2 AUX PLL Lock Output Configuration (AuxLockCfg) .............................................................. 31 8.7.3 Reference Clock Input Divider (RefClkDiv[1:0]) .................................................................... 31 8.8 Function Configuration 2 (Address 17h) ........................................................................................ 32 8.8.1 Enable PLL Clock Output on Unlock (ClkOutUnl) ................................................................. 32 8.8.2 Low-Frequency Ratio Configuration (LFRatioCfg) ................................................................ 32 8.9 Function Configuration 3 (Address 1Eh) ........................................................................................ 32 8.9.1 Clock Input Bandwidth (ClkIn_BW[2:0]) ................................................................................ 32 9. CALCULATING THE USER DEFINED RATIO .................................................................................... 33 9.1 High Resolution 12.20 Format ....................................................................................................... 33 9.2 High Multiplication 20.12 Format ................................................................................................... 33 10. PACKAGE DIMENSIONS .................................................................................................................. 34 THERMAL CHARACTERISTICS ......................................................................................................... 34 11. ORDERING INFORMATION .............................................................................................................. 35 12. REFERENCES .................................................................................................................................... 35 13. REVISION HISTORY .......................................................................................................................... 35 LIST OF FIGURES Figure 1. Typical Connection Diagram ........................................................................................................ 6 Figure 2. Control Port Timing - I²C Format .................................................................................................. 9 Figure 3. Control Port Timing - SPI Format (Write Only) .......................................................................... 10 Figure 4. Delta-Sigma Fractional-N Frequency Synthesizer ..................................................................... 11 Figure 5. Hybrid Analog-Digital PLL .......................................................................................................... 12 Figure 6. Fractional-N Source Selection Overview ................................................................................... 12 Figure 7. Internal Timing Reference Clock Divider ................................................................................... 13 Figure 8. External Component Requirements for Crystal Circuit .............................................................. 13 Figure 9. CLK_IN removed for > 223 SysClk cycles .................................................................................. 15 Figure 10. CLK_IN removed for < 223 SysClk cycles but > tCS ................................................................. 15 Figure 11. CLK_IN removed for < tCS ....................................................................................................... 15 Figure 12. Low bandwidth and new clock domain .................................................................................... 16 Figure 13. High bandwidth with CLK_IN domain re-use ........................................................................... 16 Figure 14. Ratio Feature Summary ........................................................................................................... 21 Figure 15. PLL Clock Output Options ....................................................................................................... 22 Figure 16. Auxiliary Output Selection ........................................................................................................ 22 Figure 17. Control Port Timing in SPI Mode ............................................................................................. 24 Figure 18. Control Port Timing, I²C Write .................................................................................................. 25 Figure 19. Control Port Timing, I²C Aborted Write + Read ....................................................................... 25 DS761PP1 3 CS2000-CP LIST OF TABLES Table 1. PLL Input Clock Range Indicator ................................................................................................ 14 Table 2. Ratio Modifier .............................................................................................................................. 18 Table 3. Automatic Ratio Modifier ............................................................................................................. 18 Table 4. Example Audio Oversampling Clock Generation from CLK_IN .................................................. 19 Table 5. Example 12.20 R-Values ............................................................................................................ 33 Table 6. Example 20.12 R-Values ............................................................................................................ 33 4 DS761PP1 CS2000-CP 1. PIN DESCRIPTION VD GND CLK_OUT AUX_OUT CLK_IN 1 2 3 4 5 10 9 8 7 6 SDA/CDIN SCL/CCLK AD0/CS XTI/REF_CLK XTO Pin Name VD GND CLK_OUT AUX_OUT CLK_IN XTO XTI/REF_CLK AD0/CS SCL/CCLK SDA/CDIN # 1 2 3 4 5 6 7 8 9 Pin Description Digital Power (Input) - Positive power supply for the digital and analog sections. Ground (Input) - Ground reference. PLL Clock Output (Output) - PLL clock output. Auxiliary Output (Output) - This pin outputs a buffered version of one of the input or output clocks, or a status signal, depending on register configuration. Frequency Reference Clock Input (Input) - Clock input for the Digital PLL frequency reference. Crystal Connections (XTI/XTO) / Timing Reference Clock Input (REF_CLK) (Input/Output) XTI/XTO are I/O pins for an external crystal which may be used to generate the low-jitter PLL input clock. REF_CLK is an input for an externally generated low-jitter reference clock. Address Bit 0 (I²C) / Control Port Chip Select (SPI) (Input) - AD0 is a chip address pin in I²C Mode. CS is the chip select signal in SPI Mode. Control Port Clock (Input) - SCL/CCLK is the serial clock for the serial control port in I²C and SPI mode. 10 Serial Control Data (Input/Output) - SDA is the data I/O line in I²C Mode. CDIN is the input data line for the control port interface in SPI Mode. DS761PP1 5 CS2000-CP 2. TYPICAL CONNECTION DIAGRAM Note1 Notes: 1. Resistors required for I2C operation. 0.1 µF 2 kΩ 2 kΩ 1 µF +3.3 V VD SCL/CCLK System MicroController SDA/CDIN AD0/CS CS2000-CP Frequency Reference CLK_IN XTI/REF_CLK XTO CLK_OUT To circuitry which requires a low-jitter clock To other circuitry or Microcontroller 1 or 2 AUX_OUT GND Low-Jitter Timing Reference REF_CLK 1 N.C. x XTO or Crystal XTI 2 XTO 40 pF 40 pF Figure 1. Typical Connection Diagram 6 DS761PP1 CS2000-CP 3. CHARACTERISTICS AND SPECIFICATIONS RECOMMENDED OPERATING CONDITIONS GND = 0 V; all voltages with respect to ground. (Note 1) Parameters DC Power Supply Ambient Operating Temperature (Power Applied) Commercial Grade TAC -10 +70 °C Symbol VD Min 3.1 Typ 3.3 Max 3.5 Units V Notes: 1. Device functional operation is guaranteed within these limits. Functionality is not guaranteed or implied outside of these limits. Operation outside of these limits may adversely affect device reliability. ABSOLUTE MAXIMUM RATINGS GND = 0 V; all voltages with respect to ground. Parameters DC Power Supply Input Current Digital Input Voltage (Note 1) Ambient Operating Temperature (Power Applied) Storage Temperature Symbol VD IIN VIN TA Tstg Min -0.3 -0.3 -55 -65 Max 6.0 ±10 VD + 0.4 125 150 Units V mA V °C °C WARNING: Operation at or beyond these limits may result in permanent damage to the device. Notes: 1. The maximum over/under voltage is limited by the input current except on the power supply pin. DC ELECTRICAL CHARACTERISTICS Test Conditions (unless otherwise specified): VD = 3.1 V to 3.5 V; TA = -10°C to +70°C (Commercial Grade). Parameters Power Supply Current - Unloaded Power Dissipation - Unloaded Input Leakage Current Input Capacitance High-Level Input Voltage Low-Level Input Voltage High-Level Output Voltage (IOH = -1.2 mA) Low-Level Output Voltage (IOH = 1.2 mA) (Note 2) (Note 2) Symbol ID PD IIN IC VIH VIL VOH VOL Min 70% 80% - Typ 12 40 8 - Max 18 60 ±10 30% 20% Units mA mW µA pF VD VD VD VD Notes: 2. To calculate the additional current consumption due to loading (per output pin), multiply clock output frequency by load capacitance and power supply voltage. For example, fCLK_OUT (49.152 MHz) * CL (15 pF) * VD (3.3 V) = 2.4 mA of additional current due to these loading conditions on CLK_OUT. DS761PP1 7 CS2000-CP AC ELECTRICAL CHARACTERISTICS Test Conditions (unless otherwise specified): VD = 3.1 V to 3.5 V; TA = -10°C to +70°C (Commercial Grade); CL = 15 pF. Parameters Crystal Frequency Reference Clock Input Frequency Reference Clock Input Duty Cycle Internal System Clock Frequency Clock Input Frequency (Auto R-Mod Disabled) Clock Input Frequency (Auto R-mod Enabled) Symbol fXTAL fREF_CLK DREF_CLK fSYS_CLK fCLK_IN fCLK_IN Conditions Fundamental Mode Min 8 8 45 8 50 Hz Typ 50 1.7 1.7 70 50 175 100 1 1 - Max 50 75 55 18.75 30 59 138 256 80 75 52 3.0 3.0 150 200 3 2 ±0.5 ±112 Units MHz MHz % MHz MHz kHz kHz kHz UI ns ms kHz MHz % ns ns ps rms ps rms ps rms UI ms ms ppm ppm Auto R Modifier = 1 Auto R Modifier = 0.5 Auto R Modifier = 0.25 fCLK_IN < fSYS_CLK/96 fCLK_IN > fSYS_CLK/96 (Notes 4, 5) (Note 5) Measured at VD/2 20% to 80% of VD 80% to 20% of VD (Note 6) (Notes 6, 7) (Notes 6, 8) 4 72 168 2 10 20 50 Hz 6 48 0 0 Clock Input Pulse Width (Note 3) Clock Skipping Timeout Clock Skipping Input Frequency PLL Clock Output Frequency PLL Clock Output Duty Cycle Clock Output Rise Time Clock Output Fall Time Period Jitter Base Band Jitter (100 Hz to 40 kHz) Wide Band JItter (100 Hz Corner) PLL Lock Time - CLK_IN (Note 9) PLL Lock Time - REF_CLK Output Frequency Synthesis Resolution (Note 10) pwCLK_IN tCS fCLK_SKIP fCLK_OUT tOD tOR tOF tJIT tLC tLR ferr fCLK_IN < 200 kHz fCLK_IN > 200 kHz fREF_CLK = 8 to 75 MHz High Resolution High Multiplication Notes: 3. 1 UI (unit interval) corresponds to tSYS_CLK or 1/fSYS_CLK. 4. tCS represents the time from the removal of CLK_IN by which CLK_IN must be re-applied to ensure that PLL_OUT continues while the PLL re-acquires lock. This timeout is based on the internal VCO frequency, with the minimum timeout occurring at the maximum VCO frequency. Lower VCO frequencies will result in larger values of tCS. 5. Only valid in clock skipping mode; See “CLK_IN Skipping Mode” on page 14 for more information. 6. fCLK_OUT = 24.576 MHz; Sample size = 10,000 points; AuxOutSrc[1:0] = 11. 7. In accordance with AES-12id-2006 section 3.4.2. Measurements are Time Interval Error taken with 3rd order 100 Hz to 40 kHz bandpass filter. 8. In accordance with AES-12id-2006 section 3.4.1. Measurements are Time Interval Error taken with 3rd order 100 Hz Highpass filter. 9. 1 UI (unit interval) corresponds to tCLK_IN or 1/fCLK_IN. 10. The frequency accuracy of the PLL clock output is directly proportional to the frequency accuracy of the reference clock. 8 DS761PP1 CS2000-CP CONTROL PORT SWITCHING CHARACTERISTICS- I²C FORMAT Inputs: Logic 0 = GND; Logic 1 = VD; CL = 20 pF. Parameter SCL Clock Frequency Bus Free-Time Between Transmissions Start Condition Hold Time (prior to first clock pulse) Clock Low Time Clock High Time Setup Time for Repeated Start Condition SDA Hold Time from SCL Falling SDA Setup Time to SCL Rising Rise Time of SCL and SDA Fall Time SCL and SDA Setup Time for Stop Condition Acknowledge Delay from SCL Falling Delay from Supply Voltage Stable to Control Port Ready (Note 11) Symbol fscl tbuf thdst tlow thigh tsust thdd tsud tr tf tsusp tack tdpor Min 4.7 4.0 4.7 4.0 4.7 0 250 4.7 300 100 Max 100 1 300 1000 - Unit kHz µs µs µs µs µs µs ns µs ns µs ns µs Notes: 11. Data must be held for sufficient time to bridge the transition time, tf, of SCL. VD t dpor Repeated Start Stop SDA t buf t hdst t high t hdst tf t susp SCL Stop Start t low t hdd t sud t sust tr Figure 2. Control Port Timing - I²C Format DS761PP1 9 CS2000-CP CONTROL PORT SWITCHING CHARACTERISTICS - SPI FORMAT Inputs: Logic 0 = GND; Logic 1 = VD; CL = 20 pF. Parameter CCLK Clock Frequency CCLK Edge to CS Falling CS High Time Between Transmissions CS Falling to CCLK Edge CCLK Low Time CCLK High Time CDIN to CCLK Rising Setup Time CCLK Rising to DATA Hold Time Rise Time of CCLK and CDIN Fall Time of CCLK and CDIN Delay from Supply Voltage Stable to Control Port Ready (Note 13) (Note 14) (Note 14) (Note 12) Symbol fccllk tspi tcsh tcss tscl tsch tdsu tdh tr2 tf2 tdpor Min 500 1.0 20 66 66 40 15 100 Max 6 100 100 - Unit MHz ns µs ns ns ns ns ns ns ns µs Notes: 12. tspi is only needed before first falling edge of CS after power is applied. tspi = 0 at all other times. 13. Data must be held for sufficient time to bridge the transition time of CCLK. 14. For fcclk < 1 MHz. VD tdpor CS t spi CCLK t r2 CDIN t css t scl t sch t csh t f2 t dsu tdh Figure 3. Control Port Timing - SPI Format (Write Only) 10 DS761PP1 CS2000-CP 4. ARCHITECTURE OVERVIEW 4.1 Delta-Sigma Fractional-N Frequency Synthesizer The core of the CS2000 is a Delta-Sigma Fractional-N Frequency Synthesizer which has very high-resolution for Input/Output clock ratios, low phase noise, very wide range of output frequencies and the ability to quickly tune to a new frequency. In very simplistic terms, the Fractional-N Frequency Synthesizer multiplies the Timing Reference Clock by the value of N to generate the PLL output clock. The desired output to input clock ratio is the value of N that is applied to the delta-sigma modulator (see Figure 4). The analog PLL based frequency synthesizer uses a low-jitter timing reference clock as a time and phase reference for the internal voltage controlled oscillator (VCO). The phase comparator compares the fractional-N divided clock with the original timing reference and generates a control signal. The control signal is filtered by the internal loop filter to generate the VCO’s control voltage which sets its output frequency. The delta-sigma modulator modulates the loop integer divide ratio to get the desired fractional ratio between the reference clock and the VCO output (thus the one’s density of the modulator sets the fractional value). This allows the design to be optimized for very fast lock times for a wide range of output frequencies without the need for external filter components. As with any Fractional-N Frequency Synthesizer the timing reference clock should be stable and jitter-free. Timing Reference Clock Phase Comparator Internal Loop Filter Voltage Controlled Oscillator PLL Output Fractional-N Divider Delta-Sigma Modulator N Figure 4. Delta-Sigma Fractional-N Frequency Synthesizer 4.2 Hybrid Analog-Digital Phase Locked Loop The addition of the Digital PLL and Fractional-N Logic (shown in Figure 5) to the Fractional-N Frequency Synthesizer creates the Hybrid Analog-Digital Phase Locked Loop with many advantages over classical analog PLL techniques. These advantages include the ability to operate over extremely wide frequency ranges without the need to change external loop filter components while maintaining impressive jitter reduction performance. In the Hybrid architecture, the Digital PLL calculates the ratio of the PLL output clock to the frequency reference and compares that to the desired ratio. The digital logic generates a value of N which is then applied to the Fractional-N frequency synthesizer to generate the desired PLL output frequency. Notice that the frequency and phase of the timing reference signal do not affect the output of the PLL since the digital control loop will correct for the PLL output. A major advantage of the Digital PLL is the ease with which the loop filter bandwidth can be altered. The PLL bandwidth is automatically set to a wide-bandwidth mode to quickly achieve lock and then reduced for optimal jitter rejection. DS761PP1 11 CS2000-CP Delta-Sigma Fractional-N Frequency Synthesizer Timing Reference Clock Phase Comparator Internal Loop Filter Voltage Controlled Oscillator PLL Output Fractional-N Divider Delta-Sigma Modulator Digital PLL and Fractional-N Logic N Digital Filter Frequency Reference Clock Frequency Comparator for Frac-N Generation Output to Input Ratio for Hybrid mode Figure 5. Hybrid Analog-Digital PLL 4.2.1 Fractional-N Source Selection for the Frequency Synthesizer The fractional-N value for the frequency synthesizer can be sourced from either a static ratio or a dynamic ratio generated from the digital PLL (see Figure 6). This allows for the selection between operating in the static ratio based Frequency Synthesizer Mode as a simple frequency synthesizer (for frequency generation from the Timing Reference Clock) and in the dynamic ratio based Hybrid PLL Mode (for jitter reduction and clock multiplication). Selection between these two modes can either be made automatically based on the presence of the Frequency Reference Clock or manually through register controls. . Timing Reference Clock Fractional-N Frequency Synthesizer PLL Output N Output to Input Ratio for Synthesizer Mode Frequency Reference Clock Digital PLL & Fractional-N Logic Output to Input ratio for Hybrid Mode Figure 6. Fractional-N Source Selection Overview 12 DS761PP1 CS2000-CP 5. APPLICATIONS 5.1 Timing Reference Clock Input The low jitter timing reference clock (RefClk) can be provided by either an external reference clock or an external crystal in conjunction with the internal oscillator. In order to maintain a stable and low-jitter PLL output the timing reference clock must also be stable and low-jitter; the quality of the timing reference clock directly affects the performance of the PLL and hence the quality of the PLL output. 5.1.1 Internal Timing Reference Clock Divider The Internal Timing Reference Clock (SysClk) has a smaller maximum frequency than what is allowed on the XTI/REF_CLK pin. The CS2000 supports the wider external frequency range by offering an internal divider for RefClk. The RefClkDiv[1:0] bits should be set such that SysClk, the divided RefClk, then falls within the valid range as indicated in Figure 7. Timing Reference Clock Divider ÷1 ÷2 ÷4 Timing Reference Clock XTI/REF_CLK 8 MHz < RefClk < 50 MHz (XTI) 75 MHz (REF_CLK) Internal Timing Reference Clock 8 MHz < SysClk < 18.75 MHz Fractional-N Frequency Synthesizer PLL Output RefClkDiv[1:0] N Figure 7. Internal Timing Reference Clock Divider It should be noted that the maximum allowable input frequency of the XTI/REF_CLK pin is dependent upon its configuration as either a crystal connection or external clock input. See the “AC Electrical Characteristics” on page 8 for more details. Referenced Control Register Location RefClkDiv[1:0] .......................“Reference Clock Input Divider (RefClkDiv[1:0])” on page 31 5.1.2 Crystal Connections (XTI and XTO) An external crystal may be used to generate RefClk. To accomplish this, a 20 pF fundamental mode parallel resonant crystal must be connected between the XTI and XTO pins as shown in Figure 8. As shown, nothing other than the crystal and its load capacitors should be connected to XTI and XTO. Please refer to the “AC Electrical Characteristics” on page 8 for the allowed crystal frequency range. X TI XTO 40 pF 40 pF Figure 8. External Component Requirements for Crystal Circuit DS761PP1 13 CS2000-CP 5.1.3 External Reference Clock (REF_CLK) For operation with an externally generated REF_CLK signal, XTI/REF_CLK should be connected to the reference clock source and XTO should be left unconnected or pulled low through a 47 kΩ resistor to GND. 5.2 Frequency Reference Clock Input, CLK_IN The frequency reference clock input (CLK_IN) is used in Hybrid PLL Mode by the Digital PLL and FractionalN Logic block to dynamically generate a fractional-N value for the Frequency Synthesizer (see “Hybrid Analog-Digital PLL” on page 12). The Digital PLL first compares the CLK_IN frequency to the PLL output. The Fractional-N logic block then translates the desired ratio based off of CLK_IN to one based off of the internal timing reference clock (SysClk). This allows the low-jitter timing reference clock to be used as the clock which the Frequency Synthesizer multiplies while maintaining synchronicity with the frequency reference clock through the Digital PLL. The allowable frequency range for CLK_IN is found in the “AC Electrical Characteristics” on page 8. 5.2.1 CLK_IN Frequency Detector The CLK_IN frequency range detector determines and indicates the ratio between the frequency of the internal SysClk and the CLK_IN input signal. The result of the ratio measurement is available in the read-only FsDet[1:0] bits and is also used by the device to determine the Auto R-Mod value. FsDetect[1:0] 00 01 10 11 fSysClk / fCLK_IN Ratio > 224 96 - 224 < 96 Reserved Table 1. PLL Input Clock Range Indicator Because fSysClk is known, FsDet[1:0] can then be interpreted as a range for fCLK_IN. This feature is particularly useful when used in conjunction with the Auto R-Mod feature (see section 5.3.4 on page 18). Referenced Control Register Location FsDet[1:0]..............................“PLL Input Sample Rate Indicator (FsDet[1:0]) - Read Only” section on page 27 5.2.2 CLK_IN Skipping Mode CLK_IN skipping mode allows the PLL to maintain lock even when the CLK_IN signal has missing pulses for up to 20 ms (tCS) at a time (see “AC Electrical Characteristics” on page 8 for specifications). CLK_IN skipping mode can only be used when the CLK_IN frequency is below 80 kHz. The ClkSkipEn bit enables this function. Regardless of the setting of the ClkSkipEn bit the PLL output will continue for 223 SysClk cycles (466 ms to 1048 ms) after CLK_IN is removed (see Figure 9). This is true as long as CLK_IN does not glitch or have an effective change in period as the clock source is removed, otherwise the PLL will interpret this as a change in frequency causing clock skipping and the 223 SysClk cycle time-out to be bypassed and the PLL to immediately unlock. If the prior conditions are met while CLK_IN is removed and 223 SysClk cycles pass, the PLL will unlock and the PLL_OUT state will be determined by the ClkOutUnl bit; See “PLL Clock Output” on page 22. If CLK_IN is re-applied after such time, the PLL will remain unlocked for the specified 14 DS761PP1 CS2000-CP time listed in the “AC Electrical Characteristics” on page 8 after which lock will be acquired and the PLL output will resume. 223 SysClk cycles Lock Time 223 SysClk cycles Lock Time CLK_IN ClkSkipEn=0 or 1 ClkOutUnl=0 CLK_IN ClkSkipEn=0 or 1 ClkOutUnl=1 PLL_OUT UNLOCK PLL_OUT UNLOCK = invalid clocks Figure 9. CLK_IN removed for > 223 SysClk cycles If CLK_IN is removed and then reapplied within 223 SysClk cycles but later than tCS, the ClkSkipEn bit will have no effect and the PLL output will continue until CLK_IN is re-applied (see Figure 10). Once CLK_IN is re-applied, the PLL will go unlocked only for the time it takes to acquire lock; the PLL_OUT state will be determined by the ClkOutUnl bit during this time. tCS Lock Time 223 SysClk cycles 223 SysClk cycles tCS Lock Time CLK_IN ClkSkipEn=0 or 1 ClkOutUnl=0 CLK_IN ClkSkipEn=0 or 1 ClkOutUnl=1 PLL_OUT UNLOCK PLL_OUT UNLOCK = invalid clocks Figure 10. CLK_IN removed for < 223 SysClk cycles but > tCS If CLK_IN is removed and then re-applied within tCS, the ClkSkipEn bit determines whether PLL_OUT continues while the PLL re-acquires lock (see Figure 11). When ClkSkipEn is disabled and CLK_IN is removed the PLL output will continue until CLK_IN is re-applied at which point the PLL will go unlocked only for the time it takes to acquire lock; the PLL_OUT state will be determined by the ClkOutUnl bit during this time. When ClkSkipEn is enabled and CLK_IN is removed the PLL output clock will remain continuous throughout the missing CLK_IN period including the time while the PLL re-acquires lock. tCS tCS Lock Time CLK_IN ClkSkipEn=1 ClkOutUnl=0 or 1 CLK_IN ClkSkipEn=0 ClkOutUnl=1 PLL_OUT UNLOCK PLL_OUT UNLOCK = invalid clocks tCS Lock Time CLK_IN ClkSkipEn=0 ClkOutUnl=0 PLL_OUT UNLOCK Figure 11. CLK_IN removed for < tCS Referenced Control Register Location ClkSkipEn..............................“Clock Skip Enable (ClkSkipEn)” on page 31 ClkOutUnl..............................“Enable PLL Clock Output on Unlock (ClkOutUnl)” on page 32 DS761PP1 15 CS2000-CP 5.2.3 Adjusting the Minimum Loop Bandwidth for CLK_IN The CS2000 allows the minimum loop bandwidth of the Digital PLL to be adjusted between 1 Hz and 128 Hz using the ClkIn_BW[2:0] bits. The minimum loop bandwidth of the Digital PLL directly affects the jitter transfer function; specifically, jitter frequencies below the loop bandwidth corner are passed from the PLL input directly to the PLL output without attenuation. In some applications it is desirable to have a very low minimum loop bandwidth to reject very low jitter frequencies, commonly referred to as wander. In others it may be preferable to remove only higher frequency jitter, allowing the input wander to pass through the PLL without attenuation. Typically, applications in which the PLL_OUT signal creates a new clock domain from which all other system clocks and associated data are derived will benefit from the maximum jitter and wander rejection of the lowest PLL bandwidth setting. See Figure 12. CLK_IN PLL BW = 1 Hz or PLL_OUT Wander and Jitter > 1 Hz Rejected Wander > 1 Hz Jitter MCLK Subclocks generated from new clock domain. MCLK LRCK SCLK SDATA D0 D1 LRCK SCLK SDATA D0 D1 Figure 12. Low bandwidth and new clock domain Systems in which some clocks and data are derived from the PLL_OUT signal while other clocks and data are derived from the CLK_IN signal will often require phase alignment of all the clocks and data in the system. See Figure 13. If there is substantial wander on the CLK_IN signal in these applications, it may be necessary to increase the minimum loop bandwidth allowing this wander to pass through to the CLK_OUT signal in order to maintain phase alignment. For these applications, it is advised to experiment with the loop bandwidth settings and choose the lowest bandwidth setting that does not produce system timing errors due to wandering between the clocks and data synchronous to the CLK_IN domain and those synchronous to the PLL_OUT domain. CLK_IN PLL BW = 128 Hz or PLL_OUT Jitter > 128 Hz Rejected Wander < 128 Hz Passed to Output Wander < 128 Hz Jitter MCLK MCLK LRCK SCLK SDATA D0 D1 Subclocks and data re-used from previous clock domain. LRCK SCLK SDATA D0 D1 Figure 13. High bandwidth with CLK_IN domain re-use It should be noted that manual adjustment of the minimum loop bandwidth is not necessary to acquire lock; this adjustment is made automatically by the Digital PLL. While acquiring lock, the digital loop bandwidth is automatically set to a large value. Once lock is achieved, the digital loop bandwidth will settle to the minimum value selected by the ClkIn_BW[2:0] bits. Referenced Control Register Location ClkIn_BW[2:0] .......................“Clock Input Bandwidth (ClkIn_BW[2:0])” on page 32 16 DS761PP1 CS2000-CP 5.3 5.3.1 Output to Input Frequency Ratio Configuration User Defined Ratio (RUD), Frequency Synthesizer Mode The User Defined Ratio, RUD, is a 32-bit un-signed fixed-point number which determines the basis for the desired input to output clock ratio. Up to four different ratios, Ratio0-3, can be stored in the CS2000 register space. The ratio pointed to by the RSel[1:0] bits is the currently selected ratio for the static ratio based Frequency Synthesizer Mode. The 32-bit RUD is represented in a high-resolution 12.20 format where the 12 MSBs represent the integer binary portion while the remaining 20 LSBs represent the fractional binary portion. The maximum multiplication factor is approximately 4096 with a resolution of 0.954 PPM in this configuration. See “Calculating the User Defined Ratio” on page 33 for more information. The status of internal dividers, such as the internal timing reference clock divider, are automatically taken into account. Therefore RUD is simply the desired ratio of the output to input clock frequencies. Referenced Control Register Location Ratio0-3.................................“Ratio 0 - 3 (Address 06h - 15h)” on page 30 Rsel[1:0] ................................“Ratio Selection (RSel[1:0])” on page 28 5.3.2 User Defined Ratio (RUD), Hybrid PLL Mode The same four ratio locations, Ratio0-3, are used to store the User Defined Ratios for Hybrid PLL Mode. The User Defined Ratio pointed to by the LockClk[1:0] bits is the currently selected ratio for the dynamic ratio based Hybrid PLL Mode. In addition to the High-Resolution format, a High-Multiplication format is also available. In the High-Multiplication Format Mode, the 32-bit RUD is represented in a 20.12 format where the 20 MSBs represent the integer binary portion while the remaining 12 LSBs represent the fractional binary portion. In this configuration, the maximum multiplication factor is approximately 1,048,575 with a resolution of 244 PPM. The ratio format default is 20.12. The 20.12 ratio format is only available when both the LFRatioCfg bit is cleared (20.12) and the FracNSrc bit is set (dynamic ratio). In Auto Fractional-N Source Mode (see section 5.3.6.2 on page 20) when CLK_IN is not present the LFRatioCfg bit is ignored and the ratio format is 12.20. It is recommended that the 12.20 High-Resolution format be utilized whenever the desired ratio is less than 4096 since the output frequency accuracy of the PLL is directly proportional to the accuracy of the timing reference clock and the resolution of the RUD. Referenced Control Register Location LockClk[1:0] ..........................“Lock Clock Ratio (LockClk[1:0])” section on page 29 LFRatioCfg ............................“Low-Frequency Ratio Configuration (LFRatioCfg)” on page 32 FracNSrc ...............................“Fractional-N Source for Frequency Synthesizer (FracNSrc)” section on page 30 DS761PP1 17 CS2000-CP 5.3.3 Manual Ratio Modifier (R-Mod) The manual Ratio Modifier is used to internally multiply/divide the currently addressed RUD (the Ratio0-3 stored in the register space remain unchanged). The available options for RMOD are summarized in Table 2 on page 18. The R-Mod value selected by RModSel[2:0] is always used in the calculation for the Effective Ratio (REFF), see “Effective Ratio (REFF)” on page 19. If R-Mod is not desired, RModSel[2:0] should be left at its default value of ‘000’, which corresponds to an R-Mod value of 1, thereby effectively disabling the ratio modifier. RModSel[2:0] 000 001 010 011 100 101 110 111 Ratio Modifier 1 2 4 8 0.5 0.25 0.125 0.0625 Table 2. Ratio Modifier Referenced Control Register Location Ratio0-3.................................“Ratio 0 - 3 (Address 06h - 15h)” on page 30 RModSel[2:0] ........................“R-Mod Selection (RModSel[2:0])” section on page 28 5.3.4 Automatic Ratio Modifier (Auto R-Mod) - Hybrid PLL Mode Only The Automatic R-Modifier uses the status of the CLK_IN Frequency Range Indicator (see section 5.2.1 on page 14) to implement a frequency dependent multiply of the currently addressed RUD as shown in Table 3. Like with R-Mod, the Ratio0-3 stored in the register space remain unchanged. The Automatic Ratio-Modifier is enabled by the AutoRMod bit. FsDetect[1:0] 00 01 10 fSysClk / fCLK_IN > 224 96 - 224 < 96 Auto R Modifier 1 0.5 0.25 Table 3. Automatic Ratio Modifier It is important to note that Auto R-Mod (if enabled) is applied in addition to any R-Mod already selected by the RModSel[2:0] bits and is used to calculate the Effective Ratio (see Section 5.3.5 on page 19). Auto R-Mod can be used to generate the appropriate oversampling clock (MCLK) for audio A/D and D/A converters. For example, if the clock applied to CLK_IN is the audio sample rate, Fs (also known as the word, frame or Left/Right clock), and SysClk is 12.288 MHz (REF_CLK = 12.288 MHz with RefClkDiv[1:0] 18 DS761PP1 CS2000-CP set to 10), the Frequency Range Indicator would then reflect the frequency range of the audio sample rate. An RUD of 512 would then generate the audio oversampling clocks as shown in Table 4. FsDetect[1:0] 00 01 10 Inferred Audio Sample Rate when SysClk=12.288 MHz < 54.8 kHz 54.8 kHz to 128 kHz > 128 kHz Speed Mode (used for audio converters) Single Speed Double Speed Quad Speed Audio Oversampling Clock 512 x 256 x 128 x Table 4. Example Audio Oversampling Clock Generation from CLK_IN Referenced Control Register Location Ratio0-3.................................“Ratio 0 - 3 (Address 06h - 15h)” on page 30 RModSel[2:0] ........................“R-Mod Selection (RModSel[2:0])” section on page 28 AutoRMod .............................“Auto R-Modifier Enable (AutoRMod)” on page 29 5.3.5 Effective Ratio (REFF) The Effective Ratio (REFF) is an internal calculation comprised of RUD and the appropriate modifiers, as previously described. REFF is calculated as follows: Frequency Synthesizer (Static Ratio) Mode: REFF = RUD • RMOD Hybrid PLL (Dynamic Ratio) Mode: REFF = RUD • RMOD • Auto R-Mod To simplify operation the device handles some of the ratio calculation functions automatically (such as when the internal timing reference clock divider is set). For this reason, the Effective Ratio does not need to be altered to account for internal dividers. Ratio modifiers which would produce an overflow or truncation of REFF should not be used; For example if RUD is 1024 an RMOD of 8 would produce an REFF value of 8192 which exceeds the 4096 limit of the 12.20 format. In all cases, the maximum and minimum allowable values for REFF are dictated by the frequency limits for both the input and output clocks as shown in the “AC Electrical Characteristics” on page 8. Selection of the user defined ratio from the four stored ratios is made by using the RSel[1:0] bits unless auto clock switching is enabled in which case the LockClk[1:0] bits also select the ratio (see “Manual Fractional-N Source Selection for the Frequency Synthesizer” on page 20). Referenced Control Register Location RSel[1:0] ...............................“Ratio Selection (RSel[1:0])” on page 28 LockClk[1:0] ..........................“Lock Clock Ratio (LockClk[1:0])” section on page 29 DS761PP1 19 CS2000-CP 5.3.6 Fractional-N Source Selection To select between the static ratio based Frequency Synthesizer Mode and the dynamic ratio based Hybrid PLL Mode, the source for the fractional-N value for the Frequency Synthesizer must be changed. The Fractional-N value can either be sourced directly from the Effective Ratio (static ratio) or from the output of the Digital PLL (dynamic ratio) (see Figure 14 on page 21). The setting of this function can be made manual or automatically depending on the presence of CLK_IN. 5.3.6.1 Manual Fractional-N Source Selection for the Frequency Synthesizer Manual selection of the fractional-N source for the frequency synthesizer is made by setting the FracNSrc bit to select the desired ratio source. The LockClk[1:0] bits (even if unused) must be set to the same value as the RSel[1:0] bits in order to maintain manual selectability of this function (see Section 5.3.6.2 on page 20). Referenced Control Register Location Rsel[1:0]................................ “Device Configuration 1 (Address 03h)” on page 28 LockClk[1:0] .......................... “Device Configuration 2 (Address 04h)” section on page 29 FracNSrc............................... “Device Configuration 2 (Address 04h)” section on page 29 5.3.6.2 Automatic Fractional-N Source Selection for the Frequency Synthesizer Automatic source selection allows for the selection of the frequency synthesizer’s fractional-N value to be made dependent on the presence of the CLK_IN signal. When CLK_IN is present the device will use the dynamic ratio generated from the Digital PLL and CLK_IN for Hybrid PLL Mode. When CLK_IN is not present, the device will use RefClk and the static ratio for Frequency Synthesizer Mode. Before switching to SysClk and re-acquiring lock the CS2000 will wait for 223 SysClk cycles after losing CLK_IN (see “CLK_IN Skipping Mode” on page 14). The User Defined Ratio pointed to by RSel[1:0] should contain the desired CLK_OUT to RefClk ratio to be used when CLK_IN is not present. The User Defined Ratio pointed to by LockClk[1:0] should contain the desired CLK_OUT to CLK_IN ratio to be used when CLK_IN is present. Automatic source selection is enabled when the LockClk[1:0] bits are set to point to a different User Defined Ratio from the one pointed to by the RSel[1:0] bits. When automatic source selection is enabled, the FracNSrc bit (used for manual clock selection) will be ignored. To disable the automatic source selection feature, set the LockClk[1:0] bits and the RSel[1:0] bits to the same value. The FracNSrc bit must then be used to select the desired clock used for the PLL’s frequency reference. Referenced Control Register Location RSel[1:0] ............................... “Ratio Selection (RSel[1:0])” on page 28 LockClk[1:0] .......................... “Lock Clock Ratio (LockClk[1:0])” section on page 29 FracNSrc............................... “Fractional-N Source for Frequency Synthesizer (FracNSrc)” section on page 30 20 DS761PP1 CS2000-CP 5.3.7 Ratio Configuration Summary The RUD is the user defined ratio for which up to four different values (Ratio0-3) can be stored in the register space. The RSel[1:0] or LockClk[1:0] bits then select the user defined ratio to be used (depending on if static or dynamic ratio mode is to be used). The resolution for the RUD is selectable, for the dynamic ratio mode, by setting LFRatioCfg. R-Mods can be applied to both modes whereas Auto R-Mod is only available in dynamic mode. The user defined ratio, ratio modifier, and automatic ratio modifier make up the effective ratio REFF, the final calculation used to determine the output to input clock ratio. The effective ratio is then corrected for the internal dividers. The frequency synthesizer’s fractional-N source selection is made between the static ratio (in frequency synthesizer mode) or the dynamic ratio generated from the digital PLL (in Hybrid PLL mode) by either the FracNSrc bit for manual mode or the presence of CLK_IN in automatic mode. The conceptual diagram in Figure 14 summarizes the features involved in the calculation of the ratio values used to generate the fractional-N value which controls the Frequency Synthesizer. RSel[1:0] =? LockClk[1:0] CLK_IN sense (auto selection) Effective Ratio REFF RSel[1:0] User Defined Ratio RUD Ratio 0 Ratio 1 Ratio 2 Ratio 3 CLK_IN present or FracNSrc=1 Timing Reference Clock (XTI/REF_CLK) ≠ Divide RefClkDiv[1:0] FracNSrc (manual selection) = Frequency Synthesizer PLL Output Ratio Format 12.20 only RModSel[2:0] Ratio Modifier RefClkDiv[1:0] Static Ratio CLK_IN not present or FracNSrc=0 SysClk R Correction N Dynamic Ratio 12.20 20.12 Ratio Modifier Auto R-Mod R Correction Digital PLL & Fractional N Logic LFRatioCfg LockClk[1:0] AutoRMod FsDet[1:0] Frequency Reference Clock (CLK_IN) Figure 14. Ratio Feature Summary Referenced Control Register Location Ratio0-3.................................“Ratio 0 - 3 (Address 06h - 15h)” on page 30 RSel[1:0] ...............................“Ratio Selection (RSel[1:0])” on page 28 LockClk[1:0] ..........................“Lock Clock Ratio (LockClk[1:0])” section on page 29 LFRatioCfg ............................“Low-Frequency Ratio Configuration (LFRatioCfg)” on page 32 RModSel[2:0] ........................“R-Mod Selection (RModSel[2:0])” section on page 28 AutoRMod .............................“Auto R-Modifier Enable (AutoRMod)” on page 29 FsDet[1:0]..............................“PLL Input Sample Rate Indicator (FsDet[1:0]) - Read Only” section on page 27 RefClkDiv[1:0] .......................“Reference Clock Input Divider (RefClkDiv[1:0])” on page 31 FracNSrc ...............................“Fractional-N Source for Frequency Synthesizer (FracNSrc)” section on page 30 DS761PP1 21 CS2000-CP 5.4 PLL Clock Output The PLL clock output pin (CLK_OUT) provides a buffered version of the output of the frequency synthesizer. The driver can be set to high-impedance with the ClkOutDis bit. The output from the PLL automatically drives a static low condition while the PLL is un-locked (when the clock may be unreliable). This feature can be disabled by setting the ClkOutUnl bit, however the state CLK_OUT may then be unreliable during an unlock condition. ClkOutUnl PLL Locked/Unlocked 0 0 2:1 Mux 1 0 PLL Clock Output PLLClkOut ClkOutDis 2:1 Mux PLL Output 1 PLL Clock Output Pin (CLK_OUT) Figure 15. PLL Clock Output Options Referenced Control Register Location ClkOutUnl..............................“Enable PLL Clock Output on Unlock (ClkOutUnl)” on page 32 ClkOutDis ..............................“PLL Clock Output Disable (ClkOutDis)” on page 28 5.5 Auxiliary Output The auxiliary output pin (AUX_OUT) can be mapped, as shown in Figure 16, to one of four signals: reference clock (RefClk), input clock (CLK_IN), additional PLL clock output (CLK_OUT), or a PLL lock indicator (Lock). The mux is controlled via the AuxOutSrc[1:0] bits. If AUX_OUT is set to Lock, the AuxLockCfg bit is then used to control the output driver type and polarity of the LOCK signal (see section 8.7.2 on page 31). If AUX_OUT is set to CLK_OUT the phase of the PLL Clock Output signal on AUX_OUT may differ from the CLK_OUT pin. The driver for the pin can be set to high-impedance using the AuxOutDis bit. AuxOutSrc[1:0] Timing Reference Clock (RefClk) AuxOutDis Frequency Reference Clock (CLK_IN) 4:1 Mux PLL Clock Output (PLLClkOut) AuxLockCfg PLL Lock/Unlock Indication (Lock) Auxiliary Output Pin (AUX_OUT) Figure 16. Auxiliary Output Selection Referenced Control Register Location AuxOutSrc[1:0]......................“Auxiliary Output Source Selection (AuxOutSrc[1:0])” on page 29 AuxOutDis .............................“Auxiliary Output Disable (AuxOutDis)” on page 28 AuxLockCfg...........................“AUX PLL Lock Output Configuration (AuxLockCfg)” section on page 31 22 DS761PP1 CS2000-CP 5.6 5.6.1 Clock Output Stability Considerations Output Switching CS2000 is designed such that re-configuration of the clock routing functions do not result in a partial clock period on any of the active outputs (CLK_OUT and/or AUX_OUT). In particular, enabling or disabling an output, changing the auxiliary output source between REF_CLK and CLK_OUT, changing between Frequency Synthesizer and Hybrid PLL Mode, and the automatic disabling of the output(s) during unlock will not cause a runt or partial clock period. The following exceptions/limitations exist: • • • Enabling/disabling AUX_OUT when AuxOutSrc = 11 (unlock indicator). Switching AuxOutSrc[1:0] to or from 01 (PLL clock input) and to or from 11 (unlock indicator) (Transitions between AuxOutSrc[1:0] = [00,10] will not produce a glitch). Changing the ClkOutUnl bit while the PLL is in operation. When any of these exceptions occur, a partial clock period on the output may result. 5.6.2 PLL Unlock Conditions Certain changes to the clock inputs and registers can cause the PLL to lose lock which will affect the presence the clock signal on CLK_OUT. The following outlines which conditions cause the PLL to go unlocked: • • • Changes made to the registers which affect the Fraction-N value that is used by the Frequency Synthesizer. This includes all the bits shown in Figure 14 on page 21. Any discontinuities on the Timing Reference Clock, REF_CLK. Discontinuities on the Frequency Reference Clock, CLK_IN, except when the Clock Skipping feature is enabled and the requirements of Clock Skipping are satisfied (see “CLK_IN Skipping Mode” on page 14). Gradual changes in CLK_IN frequency greater than ±30% from the starting frequency. Step changes in CLK_IN frequency. • • DS761PP1 23 CS2000-CP 6. SPI / I²C CONTROL PORT The control port is used to access the registers and allows the device to be configured for the desired operational modes and formats. The operation of the control port may be completely asynchronous with respect to device inputs and outputs. However, to avoid potential interference problems, the control port pins should remain static if no operation is required. The control port operates with either the SPI or I²C interface, with the CS2000 acting as a slave device. SPI Mode is selected if there is a high-to-low transition on the AD0/CS pin after power-up. I²C Mode is selected by connecting the AD0/CS pin through a resistor to VD or GND, thereby permanently selecting the desired AD0 bit address state. In both modes the EnDevCfg1 and EnDevCfg2 bits must be set to 1 for normal operation. WARNING: All “Reserved” registers must maintain their default state to ensure proper functional operation. Referenced Control Register Location EnDevCfg1 ............................“Enable Device Configuration Registers 1 (EnDevCfg1)” on page 29 EnDevCfg2 ............................“Enable Device Configuration Registers 2 (EnDevCfg2)” section on page 30 6.1 SPI Control In SPI Mode, CS is the chip select signal; CCLK is the control port bit clock (sourced from a microcontroller), and CDIN is the input data line from the microcontroller. Data is clocked in on the rising edge of CCLK. The device only supports write operations. Figure 17 shows the operation of the control port in SPI Mode. To write to a register, bring CS low. The first eight bits on CDIN form the chip address and must be 10011110. The next eight bits form the Memory Address Pointer (MAP), which is set to the address of the register that is to be updated. The next eight bits are the data which will be placed into the register designated by the MAP. There is MAP auto increment capability, enabled by the INCR bit in the MAP register. If INCR is a zero, the MAP will stay constant for successive read or writes. If INCR is set to a 1, the MAP will automatically increment after each byte is read or written, allowing block writes of successive registers. CS 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 CCLK CHIP ADDRESS MAP BYTE 1 0 INCR DATA 1 0 7 6 1 0 7 DATA +n 6 1 0 CDIN 1 0 0 1 1 1 6 5 4 3 2 Figure 17. Control Port Timing in SPI Mode 6.2 I²C Control In I²C Mode, SDA is a bidirectional data line. Data is clocked into and out of the device by the clock, SCL. There is no CS pin. The AD0 pin forms the least-significant bit of the chip address and should be connected to VD or GND as appropriate. The state of the AD0 pin should be maintained throughout operation of the device. The signal timings for a read and write cycle are shown in Figure 18 and Figure 19. A Start condition is defined as a falling transition of SDA while the clock is high. A Stop condition is a rising transition while the clock is high. All other transitions of SDA occur while the clock is low. The first byte sent to the CS2000 after a Start condition consists of the 7-bit chip address field and a R/W bit (high for a read, low for a write). The upper 6 bits of the 7-bit address field are fixed at 100111 followed by the logic state of the AD0 pin. The 24 DS761PP1 CS2000-CP eighth bit of the address is the R/W bit. If the operation is a write, the next byte is the Memory Address Pointer (MAP) which selects the register to be read or written. If the operation is a read, the contents of the register pointed to by the MAP will be output. Setting the auto increment bit in MAP allows successive reads or writes of consecutive registers. Each byte is separated by an acknowledge bit. The ACK bit is output from the CS2000 after each input byte is read and is input from the microcontroller after each transmitted byte. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 24 25 26 27 28 SCL CHIP ADDRESS (WRITE) MAP BYTE 0 INCR DATA 1 0 7 6 1 0 7 DATA +1 6 1 0 7 DATA +n 6 1 0 SDA 1 0 0 1 1 1 AD0 6 5 4 3 2 ACK START ACK ACK ACK STOP Figure 18. Control Port Timing, I²C Write 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 SCL CHIP ADDRESS (WRITE) MAP BYTE INCR STOP 1 0 1 CHIP ADDRESS (READ) 0 0 1 0 1 AD0 1 DATA 7 0 DATA +1 7 0 DATA + n 7 0 SDA 1 0 0 1 1 1 AD0 0 6 5 4 3 2 ACK START ACK START ACK ACK NO ACK STOP Figure 19. Control Port Timing, I²C Aborted Write + Read Since the read operation cannot set the MAP, an aborted write operation is used as a preamble. As shown in Figure 18, the write operation is aborted after the acknowledge for the MAP byte by sending a stop condition. The following pseudocode illustrates an aborted write operation followed by a read operation. Send start condition. Send 100111x0 (chip address & write operation). Receive acknowledge bit. Send MAP byte, auto increment off. Receive acknowledge bit. Send stop condition, aborting write. Send start condition. Send 100111x1(chip address & read operation). Receive acknowledge bit. Receive byte, contents of selected register. Send acknowledge bit. Send stop condition. Setting the auto increment bit in the MAP allows successive reads or writes of consecutive registers. Each byte is separated by an acknowledge bit. DS761PP1 25 CS2000-CP 6.3 Memory Address Pointer The Memory Address Pointer (MAP) byte comes after the address byte and selects the register to be read or written. Refer to the pseudocode above for implementation details. 6.3.1 Map Auto Increment The device has MAP auto increment capability enabled by the INCR bit (the MSB) of the MAP. If INCR is set to 0, MAP will stay constant for successive I²C writes or reads and SPI writes. If INCR is set to 1, MAP will auto increment after each byte is read or written, allowing block reads or writes of successive registers. 7. REGISTER QUICK REFERENCE This table shows the register and bit names with their associated default values. EnDevCfg1 and EnDevCfg2 bits must be set to 1 for normal operation. WARNING: All “Reserved” registers must maintain their default state to ensure proper functional operation. Adr p 27 02h Device Ctrl p 27 03h Device Cfg 1 p 28 04h Device Cfg 2 p 29 05h Global Cfg p 30 06h 32-Bit Ratio 0 09h Name 7 6 5 4 3 2 1 0 Revision0 x ClkOutDis 0 EnDevCfg1 0 FracNSrc 0 EnDevCfg2 0 MSB-7 MSB-15 LSB+8 LSB MSB-7 MSB-15 LSB+8 LSB MSB-7 MSB-15 LSB+8 LSB MSB-7 MSB-15 LSB+8 LSB Reserved 0 Reserved 0 Reserved 0 01h Device ID 0Ah 32-Bit Ratio 1 0Dh 0Eh 32-Bit Ratio 2 11h 12h 32-Bit Ratio 3 15h 16h Funct Cfg 1 p 31 17h Funct Cfg 2 p 32 1Eh Funct Cfg 3 p 32 Device4 Device3 Device2 Device1 Device0 Revision2 Revision1 0 0 0 0 0 x x Unlock FsDet1 FsDet0 Reserved Reserved Reserved AuxOutDis x x x 0 0 0 0 RModSel2 RModSel1 RModSel0 RSel1 RSel0 AuxOutSrc1 AuxOutSrc0 0 0 0 0 0 0 0 Reserved Reserved Reserved Reserved AutoRMod LockClk1 LockClk0 0 0 0 0 0 0 0 Reserved Reserved Reserved Reserved Freeze Reserved Reserved 0 0 0 0 0 0 0 MSB ........................................................................................................................... MSB-8 ........................................................................................................................... LSB+15 ........................................................................................................................... LSB+7 ........................................................................................................................... MSB ........................................................................................................................... MSB-8 ........................................................................................................................... LSB+15 ........................................................................................................................... LSB+7 ........................................................................................................................... MSB ........................................................................................................................... MSB-8 ........................................................................................................................... LSB+15 ........................................................................................................................... LSB+7 ........................................................................................................................... MSB ........................................................................................................................... MSB-8 ........................................................................................................................... LSB+15 ........................................................................................................................... LSB+7 ........................................................................................................................... ClkSkipEn AuxLockCfg Reserved RefClkDiv1 RefClkDiv0 Reserved Reserved 0 0 0 0 0 0 0 Reserved Reserved Reserved ClkOutUnl LFRatioCfg Reserved Reserved 0 0 0 0 0 0 0 Reserved ClkIn_BW2 ClkIn_BW1 ClkIn_BW0 Reserved Reserved Reserved 0 0 0 0 0 0 0 26 DS761PP1 CS2000-CP 8. REGISTER DESCRIPTIONS In I²C Mode all registers are read/write unless otherwise stated. In SPI mode all registers are write only. All “Reserved” registers must maintain their default state to ensure proper functional operation. The default state of each bit after a power-up sequence or reset is indicated by the shaded row in the bit decode table and in the “Register Quick Reference” on page 26. Control port mode is entered when the device recognizes a valid chip address input on its I²C/SPI serial control pins and the EnDevCfg1 and EnDevCfg2 bits are set to 1. 8.1 Device I.D. and Revision (Address 01h) 6 Device3 5 Device2 4 Device1 3 Device0 2 Revision2 1 Revision1 0 Revision0 7 Device4 8.1.1 Device Identification (Device[4:0]) - Read Only I.D. code for the CS2000. Device[4:0] 00000 Device CS2000. 8.1.2 Device Revision (Revision[2:0]) - Read Only CS2000 revision level. REVID[2:0] 100 Revision Level B2. 8.2 Device Control (Address 02h) 7 Unlock 6 FsDet1 5 FsDet0 4 Reserved 3 Reserved 2 Reserved 1 AuxOutDis 0 ClkOutDis 8.2.1 Unlock Indicator (Unlock) - Read Only Indicates the lock state of the PLL. Unlock 0 1 PLL Lock State PLL is Locked. PLL is Unlocked. 8.2.2 PLL Input Sample Rate Indicator (FsDet[1:0]) - Read Only Indicates the range of the frequency of CLK_IN relative to the frequency of SysClk. For audio applications, this can be used to distinguish single-, double-, and quad-speed modes. FsDet[1:0] 00 01 10 11 Application: fSysClk / fCLK_IN > 224. 96 to 224. < 96. Reserved. “CLK_IN Frequency Detector” on page 14 DS761PP1 27 CS2000-CP 8.2.3 Auxiliary Output Disable (AuxOutDis) This bit controls the output driver for the AUX_OUT pin. AuxOutDis 0 1 Application: Output Driver State AUX_OUT output driver enabled. AUX_OUT output driver set to high-impedance. “Auxiliary Output” on page 22 8.2.4 PLL Clock Output Disable (ClkOutDis) This bit controls the output driver for the CLK_OUT pin. ClkOutDis 0 1 Application: Output Driver State CLK_OUT output driver enabled. CLK_OUT output driver set to high-impedance. “PLL Clock Output” on page 22 8.3 Device Configuration 1 (Address 03h) 6 RModSel1 5 RModSel0 4 RSel1 3 RSel0 2 AuxOutSrc1 1 AuxOutSrc0 0 EnDevCfg1 7 RModSel2 8.3.1 R-Mod Selection (RModSel[2:0]) Selects the R-Mod value, which is used as a factor in determining the PLL’s Fractional N. RModSel[2:0] 000 001 010 011 100 101 110 111 Application: R-Mod Selection Left-shift R-value by 0 (x 1). Left-shift R-value by 1 (x 2). Left-shift R-value by 2 (x 4). Left-shift R-value by 3 (x 8). Right-shift R-value by 1 (÷ 2). Right-shift R-value by 2 (÷ 4). Right-shift R-value by 3 (÷ 8). Right-shift R-value by 4 (÷ 16). “Manual Ratio Modifier (R-Mod)” on page 18 8.3.2 Ratio Selection (RSel[1:0]) Selects one of the four stored User Defined Ratios for use in the static ratio based Frequency Synthesizer Mode. RSel[1:0] 00 01 10 11 Application: Ratio Selection Ratio 0. Ratio 1. Ratio 2. Ratio 3. “User Defined Ratio (RUD), Frequency Synthesizer Mode” on page 17 28 DS761PP1 CS2000-CP 8.3.3 Auxiliary Output Source Selection (AuxOutSrc[1:0]) Selects the source of the AUX_OUT signal. AuxOutSrc[1:0] 00 01 10 11 Application: Auxiliary Output Source RefClk. CLK_IN. CLK_OUT. PLL Lock Status Indicator. “Auxiliary Output” on page 22 Note: When set to 11, AuxLckCfg sets the polarity and driver type (“AUX PLL Lock Output Configuration (AuxLockCfg)” on page 31). 8.3.4 Enable Device Configuration Registers 1 (EnDevCfg1) This bit, in conjunction with EnDevCfg2, enables control port mode. Both bits must be set to 1 during initialization. EnDevCfg1 0 1 Application: Register State Disabled. Enabled. “SPI / I²C Control Port” on page 24 Note: EnDevCfg2 must also be set to enable control port mode (“SPI / I²C Control Port” on page 24). 8.4 Device Configuration 2 (Address 04h) 6 Reserved 5 Reserved 4 Reserved 3 AutoRMod 2 LockClk1 1 LockClk0 0 FracNSrc 7 Reserved 8.4.1 Auto R-Modifier Enable (AutoRMod) Controls the automatic ratio modifier function. AutoRMod 0 1 Application: Automatic R-Mod State Disabled. Enabled. “Automatic Ratio Modifier (Auto R-Mod) - Hybrid PLL Mode Only” on page 18 8.4.2 Lock Clock Ratio (LockClk[1:0]) Selects one of the four stored User Defined Ratios for use in the dynamic ratio based Hybrid PLL Mode. LockClk[1:0] 00 01 10 11 Application: CLK_IN Ratio Selection Ratio 0. Ratio 1. Ratio 2. Ratio 3. Section 5.3.2 on page 17 DS761PP1 29 CS2000-CP 8.4.3 Fractional-N Source for Frequency Synthesizer (FracNSrc) Selects static or dynamic ratio mode when auto clock switching is disabled. FracNSrc 0 1 Application: Fractional-N Source Selection Static Ratio directly from REFF for Frequency Synthesizer Mode Dynamic Ratio from Digital PLL for Hybrid PLL Mode “Fractional-N Source Selection” on page 20 8.5 Global Configuration (Address 05h) 6 Reserved 5 Reserved 4 Reserved 3 Freeze 2 Reserved 1 Reserved 0 EnDevCfg2 7 Reserved 8.5.1 Device Configuration Freeze (Freeze) Setting this bit allows writes to the Device Control and Device Configuration registers (address 02h - 04h) but keeps them from taking effect until this bit is cleared. FREEZE 0 1 Device Control and Configuration Registers Register changes take effect immediately. Modifications may be made to Device Control and Device Configuration registers (registers 02h-04h) without the changes taking effect until after the FREEZE bit is cleared. 8.5.2 Enable Device Configuration Registers 2 (EnDevCfg2) This bit, in conjunction with EnDevCfg1, enables control port mode. Both bits must be set to 1 during initialization. EnDevCfg2 0 1 Application: Register State Disabled. Enabled. “SPI / I²C Control Port” on page 24 Note: EnDevCfg1 must also be set to enable control port mode (“SPI / I²C Control Port” on page 24). 8.6 Ratio 0 - 3 (Address 06h - 15h) 6 5 4 3 2 1 ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... 0 MSB-7 MSB-15 LSB+8 LSB 7 MSB MSB-8 LSB+15 LSB+7 These registers contain the User Defined Ratios as shown in the “Register Quick Reference” section on page 26. Each group of 4 registers forms a single 32-bit ratio value as shown above. See “Output to Input Frequency Ratio Configuration” on page 17 and “Calculating the User Defined Ratio” on page 33 for more details. 30 DS761PP1 CS2000-CP 8.7 Function Configuration 1 (Address 16h) 6 AuxLockCfg 5 Reserved 4 RefClkDiv1 3 RefClkDiv0 2 Reserved 1 Reserved 0 Reserved 7 ClkSkipEn 8.7.1 Clock Skip Enable (ClkSkipEn) This bit enables clock skipping mode for the PLL and allows the PLL to maintain lock even when the CLK_IN has missing pulses. ClkSkipEn 0 1 Application: PLL Clock Skipping Mode Disabled. Enabled. “CLK_IN Skipping Mode” on page 14 Note: fCLK_IN must be < 80 kHz to use this feature. 8.7.2 AUX PLL Lock Output Configuration (AuxLockCfg) When the AUX_OUT pin is configured as a lock indicator (AuxOutSrc[1:0] = 11), this bit configures the AUX_OUT driver to either push-pull or open drain. It also determines the polarity of the lock signal. If AUX_OUT is configured as a clock output, the state of this bit is disregarded. AuxLockCfg 0 1 Application: AUX_OUT Driver Configuration Push-Pull, Active High (output ‘high’ for unlocked condition, ‘low’ for locked condition). Open Drain, Active Low (output ‘low’ for unlocked condition, high-Z for locked condition). “Auxiliary Output” on page 22 Note: AUX_OUT is an unlock indicator, signalling an error condition when the PLL is unlocked. Therefore, the pin polarity is defined relative to the unlock condition. 8.7.3 Reference Clock Input Divider (RefClkDiv[1:0]) Selects the input divider for the timing reference clock. RefClkDiv[1:0] 00 01 10 11 Application: Reference Clock Input Divider ÷ 4. ÷ 2. ÷ 1. Reserved. “Internal Timing Reference Clock Divider” on page 13 REF_CLK Frequency Range 32 MHz to 75 MHz (50 MHz with XTI) 16 MHz to 37.5 MHz 8 MHz to 18.75 MHz DS761PP1 31 CS2000-CP 8.8 Function Configuration 2 (Address 17h) 6 Reserved 5 Reserved 4 ClkOutUnl 3 LFRatioCfg 2 Reserved 1 Reserved 0 Reserved 7 Reserved 8.8.1 Enable PLL Clock Output on Unlock (ClkOutUnl) Defines the state of the PLL output during the PLL unlock condition. ClkOutUnl 0 1 Application: Clock Output Enable Status Clock outputs are driven ‘low’ when PLL is unlocked. Clock outputs are always enabled (results in unpredictable output when PLL is unlocked). “PLL Clock Output” on page 22 8.8.2 Low-Frequency Ratio Configuration (LFRatioCfg) Determines how to interpret the currently indexed 32-bit User Defined Ratio when the dynamic ratio based Hybrid PLL Mode is selected (either manually or automatically, see section 5.3.6 on page 20). LFRatioCfg 0 1 Application: Ratio Bit Encoding Interpretation when Input Clock Source is CLK_IN 20.12 - High Multiplier. 12.20 - High Accuracy. “User Defined Ratio (RUD), Hybrid PLL Mode” on page 17 Note: When the static ratio based Frequency Synthesizer Mode is selected (either manually or automatically), the currently indexed User Defined Ratio will always be interpreted as a 12.20 fixed point value, regardless of the state of this bit. 8.9 Function Configuration 3 (Address 1Eh) 6 ClkIn_BW2 5 ClkIn_BW1 4 ClkIn_BW0 3 Reserved 2 Reserved 1 Reserved 0 Reserved 7 Reserved 8.9.1 Clock Input Bandwidth (ClkIn_BW[2:0]) Sets the minimum loop bandwidth when locked to CLK_IN. ClkIn_BW[2:0] 000 001 010 011 100 101 110 111 Application: Minimum Loop Bandwidth 1 Hz 2 Hz 4 Hz 8 Hz 16 Hz 32 Hz 64 Hz 128 Hz “Adjusting the Minimum Loop Bandwidth for CLK_IN” on page 16 Note: In order to guarantee that a change in minimum bandwidth takes effect, these bits must be set prior to acquiring lock (removing and re-applying CLK_IN can provide the unlock condition necessary to initiate the setting change). In production systems these bits should be configured with the desired values prior to setting the EnDevCfg bits; this guarantees that the setting takes effect prior to acquiring lock. 32 DS761PP1 CS2000-CP 9. CALCULATING THE USER DEFINED RATIO Note: The software for use with the evaluation kit has built in tools to aid in calculating and converting the User Defined Ratio. This section is for those who are not interested in the software or who are developing their systems without the aid of the evaluation kit. Most calculators do not interpret the fixed point binary representation which the CS2000 uses to define the output to input clock ratio (see Section 5.3.1 on page 17); However, with a simple conversion we can use these tools to generate a binary or hex value which can be written to the Ratio0-3 registers. 9.1 High Resolution 12.20 Format To calculate the User Defined Ratio (RUD) to store in the register(s), divide the desired output clock frequency by the given input clock (CLK_IN or RefClk). Then multiply the desired ratio by the scaling factor of 220 to get the scaled decimal representation; then use the decimal to binary/hex conversion function on a calculator and write to the register. A few examples have been provided in Table 5. Desired Output to Input Clock Ratio (output clock/input clock) 12.288 MHz/10 MHz=1.2288 11.2896 MHz/44.1 kHz=256 Scaled Decimal Representation = (output clock/input clock) • 220 1288490 268435456 Hex Representation of Binary RUD 00 13 A9 2A 10 00 00 00 Table 5. Example 12.20 R-Values 9.2 High Multiplication 20.12 Format To calculate the User Defined Ratio (RUD) to store in the register(s), divide the desired output clock frequency by the given input clock (CLK_IN). Then multiply the desired ratio by the scaling factor of 212 to get the scaled decimal representation; then use the decimal to binary/hex conversion function on a calculator and write to the register. A few examples have been provided in Table 6. Desired Output to Input Clock Ratio (output clock/input clock) 12.288 MHz/60 Hz=204,800 11.2896 MHz/59.97 Hz =188254.127... Scaled Decimal Representation = (output clock/input clock) • 212 838860800 771088904 Hex Representation of Binary RUD 32 00 00 00 2D F5 E2 08 Table 6. Example 20.12 R-Values DS761PP1 33 CS2000-CP 10.PACKAGE DIMENSIONS 10L MSOP (3 mm BODY) PACKAGE DRAWING (Note 1) N D c E A2 A1 L E11 A ∝ e b END VIEW SIDE VIEW SEATING PLANE L1 123 TOP VIEW DIM A A1 A2 b c D E E1 e L L1 MIN -0 0.0295 0.0059 0.0031 ----0.0157 -- INCHES NOM -----0.1181 BSC 0.1929 BSC 0.1181 BSC 0.0197 BSC 0.0236 0.0374 REF MAX 0.0433 0.0059 0.0374 0.0118 0.0091 ----0.0315 -- MIN -0 0.75 0.15 0.08 ----0.40 -- MILLIMETERS NOM -----3.00 BSC 4.90 BSC 3.00 BSC 0.50 BSC 0.60 0.95 REF NOTE MAX 1.10 0.15 0.95 0.30 0.23 ----0.80 -- 4, 5 2 3 Notes: 1. Reference document: JEDEC MO-187 2. D does not include mold flash or protrusions which is 0.15 mm max. per side. 3. E1 does not include inter-lead flash or protrusions which is 0.15 mm max per side. 4. Dimension b does not include a total allowable dambar protrusion of 0.08 mm max. 5. Exceptions to JEDEC dimension. THERMAL CHARACTERISTICS Parameter Junction to Ambient Thermal Impedance JEDEC 2-Layer JEDEC 4-Layer Symbol θJA θJA Min - Typ 170 100 Max - Units °C/W °C/W 34 DS761PP1 CS2000-CP 11.ORDERING INFORMATION Product CS2000-CP CS2000-CP CDK2000 Description Clocking Device Clocking Device Evaluation Platform Package 10L-MSOP 10L-MSOP - Pb-Free Yes Yes Yes Grade Commercial - Temp Range Container -10° to +70°C -10° to +70°C Rail Tape and Reel - Order# CS2000-CP-CZZ CS2000-CP-CZZR CDK-2000-CLK 12.REFERENCES 1. Audio Engineering Society AES-12id-2006: “AES Information Document for digital audio measurements Jitter performance specifications,” May 2007. 2. Philips Semiconductor, “The I²C-Bus Specification: Version 2,” Dec. 1998. http://www.semiconductors.philips.com 13.REVISION HISTORY Release A1 A2 A3 Initial Release Updated AC Electrical Characteristics Updated text for readability Updated application section for “CLK_IN Skipping Mode” on page 14 Added application section for “Adjusting the Minimum Loop Bandwidth for CLK_IN” on page 16 Added register description for “Clock Input Bandwidth (ClkIn_BW[2:0])” on page 32 Updated “AC Electrical Characteristics” on page 8 Changes PP1 Contacting Cirrus Logic Support For all product questions and inquiries, contact a Cirrus Logic Sales Representative. To find one nearest you, go to www.cirrus.com IMPORTANT NOTICE “Preliminary” product information describes products that are in production, but for which full characterization data is not yet available. Cirrus Logic, Inc. and its subsidiaries (“Cirrus”) believe that the information contained in this document is accurate and reliable. However, the information is subject to change without notice and is provided “AS IS” without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those pertaining to warranty, indemnification, and limitation of liability. No responsibility is assumed by Cirrus for the use of this information, including use of this information as the basis for manufacture or sale of any items, or for infringement of patents or other rights of third parties. This document is the property of Cirrus and by furnishing this information, Cirrus grants no license, express or implied under any patents, mask work rights, copyrights, trademarks, trade secrets or other intellectual property rights. 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INCLUSION OF CIRRUS PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER’S RISK AND CIRRUS DISCLAIMS AND MAKES NO WARRANTY, EXPRESS, STATUTORY OR IMPLIED, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR PARTICULAR PURPOSE, WITH REGARD TO ANY CIRRUS PRODUCT THAT IS USED IN SUCH A MANNER. IF THE CUSTOMER OR CUSTOMER’S CUSTOMER USES OR PERMITS THE USE OF CIRRUS PRODUCTS IN CRITICAL APPLICATIONS, CUSTOMER AGREES, BY SUCH USE, TO FULLY INDEMNIFY CIRRUS, ITS OFFICERS, DIRECTORS, EMPLOYEES, DISTRIBUTORS AND OTHER AGENTS FROM ANY AND ALL LIABILITY, INCLUDING ATTORNEYS’ FEES AND COSTS, THAT MAY RESULT FROM OR ARISE IN CONNECTION WITH THESE USES. Cirrus Logic, Cirrus, and the Cirrus Logic logo designs are trademarks of Cirrus Logic, Inc. All other brand and product names in this document may be trademarks or service marks of their respective owners. I²C is a registered trademark of Philips Semiconductor. SPI is a trademark of Motorola, Inc. DS761PP1 35 CS2000-CP 36 DS761PP1