MK2059-01 VCXO-Based Frame Clock Frequency Translator Description Features The MK2059-01 is a VCXO (Voltage Controlled Crystal Oscillator) based clock generator that produces common telecommunications reference frequencies. The output clock is phase locked to an 8kHz (frame rate) input reference clock. The MK2059-01 also provides jitter attenuation. Included in the selection of output frequencies are these common system clocks: * Generates T1, E1, OC-3 and other common telecom * * * 1.544 MHz (T1) 2.048 (E1) * 19.44 MHz (OC-3) 16.384 MHz (8x E1) * * This monolithic IC, combined with an external inexpensive quartz crystal, can be used to replace a more costly hybrid VCXO retiming module. Through selection of external loop filter components, the PLL loop bandwidth and damping factor can be tailored to meet input clock jitter attenuation requirements. A loop bandwidth down to the Hz range is possible. * * * * clock frequencies from an 8kHz frame clock Configurable jitter attenuation characterisitics, excellent for use as a Stratum source de-jitter circuit 2:1 Input MUX for input reference clocks VCXO-based clock generation offers very low jitter and phase noise generation Output clock is phase and frequency locked to the selected input reference clock Fixed input to output phase relationship +115ppm minimum crystal frequency pullability range, using recommended crystal Industrial temperature range Low power CMOS technology 20 pin SOIC package Single 3.3V power supply Block Diagram P ullable x tal X1 IS E T 8kH z R ef In p ut 8kH z R ef In p ut IC L K 2 1 IC L K 1 0 P h ase D etecto r X2 VD D VDD 3 O u tpu t D ivid er V C XO CLK C harg e P um p ISE L F eedb ack D ivid er S EL 2:0 3 CHGP MDS 2059-01 B 1 VIN GND 4 Revision 071001 Integrated Circuit Systems, Inc. 525 Race Street, San Jose, CA 95126 tel (408) 295-9800 www.icst.com MK2059-01 VCXO-Based Frame Clock Frequency Translator Pin Assignment X1 VD D VD D VD D V IN GN D GN D GN D CHG P ISE T Output Clock Selection Table 1 20 X2 2 3 4 5 6 7 8 9 10 19 18 17 16 15 14 13 12 11 GND IS E L IC L K 1 IC L K 2 S EL 0 CLK NC S EL 1 S EL 2 Input SEL2 SEL1 SEL0 8 kHz 8 kHz 8 kHz 8 kHz 8 kHz 8 kHz 8 kHz 8 kHz 8 kHz 8 kHz 8 kHz 8 kHz 0 0 0 0 M M M M 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 Output Clock (MHz) 1.544 2.048 16.384 17.664 18.528 20.00 25.00 25.92 19.44 20.48 24.704 24.576 Crystal Used (MHz) 24.704 24.576 16.384 17.664 18.528 20.00 25.00 25.92 19.44 20.48 24.704 24.576 Note: For SEL input pin programming: 0 = GND, 1 = VDD, M = Floating 20 pin 300 mil SOIC Pin Descriptions Pin Number Pin Name Pin Type Pin Description 1 2 3 4 5 X1 VDD VDD VDD VIN Power Power Power Input 6 7 8 9 GND GND GND CHGP Power Power Power Output 10 11 ISET SEL2 Input 12 SEL1 Input 13 14 15 NC CLK SEL0 Input Output Input 16 ICLK2 Input 17 ICLK1 Input 18 ISEL Input 19 20 GND X2 Power - Crystal Input. Connect this pin to the specified crystal. Power Supply. Connect to +3.3V. Power Supply. Connect to +3.3V. Power Supply. Connect to +3.3V. VCXO Control Voltage Input. Connect this pin to CHGP pin and the external loop filter as shown in this data sheet. Connect to ground Connect to ground Connect to ground Charge Pump Output. Connect this pin to the external loop filter and to pin VIN. Charge pump current setting node, connection for setting resistor. Output Frequency Selection Pin 2. Determines output frequency as per table above. Internally biased to VDD/2. Output Frequency Selection Pin 1. Determines output frequency as per table above. Internal pull-up. No Internal Connection. Clock Output Output Frequency Selection Pin 0. Determines output frequency as per table above. Internal pull-up. Input Clock Connection 2. Connect an input reference clock to this pin. If unused, connect to ground. Input Clock Connection 1. Connect an input reference clock to this pin. If unused, connect to ground. Input Selection. Used to select which reference input clock is active. Low input level selects ICLK1, high input level selects ICLK2. Internal pull-up. Connect to ground. Crystal Output. Connect this pin to the specified crystal. MDS 2059-01 B 2 Revision 071001 Integrated Circuit Systems, Inc. 525 Race Street, San Jose, CA 95126 tel (408) 295-9800 www.icst.com MK2059-01 VCXO-Based Frame Clock Frequency Translator Functional Description Quartz Crystal The MK2059-01 is a clock generator IC that generates an output clock directly from an internal VCXO circuit which works in conjunction with an external quartz crystal. The VCXO is controlled by an internal PLL (Phase Locked Loop) circuit, enabling the device to perform clock regeneration from an input reference clock. The MK2059-01 is configured to provide a MHz communications reference clock output from an 8kHz input clock. There are 12 selectable output frequencies. Please refer to the Output Clock Selection Table on Page 2. It is important that the correct type of quartz crystal is used with the MK2059-01. Failure to do so may result in reduced frequency pullability range, inability of the loop to lock, or excessive output phase jitter. Most typical PLL clock devices use an internal VCO (Voltage Controlled Oscillator) for output clock generation. By using a VCXO with an external crystal, the MK2059-01 is able to generate a low jitter, low phase-noise output clock within a low bandwidth PLL. This serves to provide input clock jitter attenuation and enables stable operation with a low frequency reference clock. The VCXO circuit requires an external pullable crystal for operation. External loop filter components enable a PLL configuration with low loop bandwidth. The MK2059-01 operates by phase-locking the VCXO circuit to the input signal of the selected ICLK input. The VCXO consists of the external crystal and the integrated VCXO oscillator circuit. To achieve the best performance and reliability, a crystal device with the recommended parameters (shown below) must be used, and the layout guidelines discussed in the PCB Layout Recommendations section must be followed. The frequency of oscillation of a quartz crystal is determined by its cut and by the external load capacitance. The MK2059-01 incorporates variable load capacitors on-chip which "pull", or change, the frequency of the crystal. The crystals specified for use with the MK2059-01 are designed to have zero frequency error when the total of on-chip + stray capacitance is 14pF. To achieve this, the layout should use short traces between the MK2059-01 and the crystal. A complete description of the recommended crystal parameters is shown below. Application Information Recommended Crystal Parameters: Output Frequency Configuration The MK2059-01 is configured to generate a set of output frequencies from an 8kHz input clock. Please refer to the Output Clock Selection Table on Page 2. Input bits SEL2:0 are set according to this table, as is the external crystal frequency. Please refer to the Quartz Crystal section on this page regarding external crystal requirements. Input Mux The Input Mux serves to select between two alternate input reference clocks. Upon reselection of the input clock, clock glitches on the output clock will not be generated due to the "fly-wheel" effect of the VCXO (the quartz crystal is a high-Q tuned circuit). When the input clocks are not phase aligned, the phase of the output clock will change to reflect the phase of newly selected input at a controlled phase slope (rate of phase change) as influenced by the PLL loop characteristics. MDS 2059-01 B 3 Operating Temperature Range Commercial Applications Industrial Applications Initial Accuracy at 25C Temperature Stability Aging Load Capacitance Shunt Capacitance, C0 C0/C1 Ratio Equivalent Series Resistance 0 to 70C -40 to 85C 20 ppm 30 ppm 20 ppm Note 1 7 pF Max 250 Max 35 Max Note 1: For crystal frequencies between 13.5MHz and 27MHz the nominal crystal load capacitance specification should be 14pF. Contact ICS MicroClock applications at (408) 297-1201 regarding the use of a crystal below 13.5MHz. To obtain a list of qualified crystal devices that meet these requirements, please contact ICS MicroClock applications department. Revision 071001 Integrated Circuit Systems, Inc. 525 Race Street, San Jose, CA 95126 tel (408) 295-9800 www.icst.com MK2059-01 VCXO-Based Frame Clock Frequency Translator External Component Schematic PLL Loop Filter Components All analog PLL circuits use a loop filter to establish operating stability. The MK2059-01 uses external loop filter components for the following reasons: 1) Larger loop filter capacitor values can be used, allowing a lower loop bandwidth. This enables the use of lower input clock reference frequencies and also input clock jitter attenuation capabilities. Larger loop filter capacitors also allow higher loop damping factors when less passband peaking is desired. 2) The loop filter values can be user selected to optimize loop response characteristics for a given application. CL Do n't S tuff (R efer to O ptional C ry stal T uning section) Xtal X1 VDD VDD VDD VIN C2 Referencing the External Component Schematic on this page, the external loop filter is made up of components RZ, C1 and C2. RSET establishes PLL charge pump current and therefore influences loop filter characteristics. CL RZ G ND C1 G ND C HG P G ND IS ET 1 2 20 19 3 4 5 6 7 8 9 10 18 17 16 15 14 13 12 11 X2 G ND IS EL IC LK 1 IC LK 2 S EL0 C LK NC S EL1 S EL2 R S ET Recommended Loop Filter Values Vs. Output Frequency Range Selection Crystal SEL2 SEL1 SEL0 Multiplier 0 0 0 0 M M M M 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 (N) 3088 3072 2048 2208 2316 2500 3125 3240 2430 2560 3088 3072 RSET RZ C1 C2 120 k 120 k 120 k 120 k 120 k 120 k 120 k 120 k 120 k 120 k 120 k 120 k 1.0 M 1.0 M 1.0 M 1.0 M 1.0 M 1.0 M 1.0 M 1.0 M 1.0 M 1.0 M 1.0 M 1.0 M 0.1 F 0.1 F 0.1 F 0.1 F 0.1 F 0.1 F 0.1 F 0.1 F 0.1 F 0.1 F 0.1 F 0.1 F 4.7 nF 4.7 nF 4.7 nF 4.7 nF 4.7 nF 4.7 nF 4.7 nF 4.7 nF 4.7 nF 4.7 nF 4.7 nF 4.7 nF Loop Bandwidth Damping Factor (-3dB point) 18 Hz 19 Hz 27 Hz 26 Hz 24 Hz 22 Hz 18 Hz 17 Hz 23 Hz 22 Hz 18 Hz 19 Hz 1.4 1.4 1.7 1.7 1.6 1.6 1.4 1.4 1.6 1.6 1.4 1.4 Note: For SEL input pin programming: 0 = GND, 1 = VDD, M = Floating MDS 2059-01 B 4 Revision 071001 Integrated Circuit Systems, Inc. 525 Race Street, San Jose, CA 95126 tel (408) 295-9800 www.icst.com MK2059-01 VCXO-Based Frame Clock Frequency Translator A "normalized" PLL loop bandwidth may be calculated as follows: R Z x I CP x 575 NBW = --------------------------------------N The "normalized" bandwidth equation above does not take into account the effects of damping factor or the second pole. However, it does provide a useful approximation of filter performance. The loop damping factor is calculated as follows: 1) The loop capacitors should be a low-leakage type to avoid leakage-induced phase noise. For this reason, DO NOT use any type of polarized or electrolytic capacitors. 2) Microphonics (mechanical board vibration) can also induce output phase noise, especially when the loop bandwidth is less than 1kHz. For this reason, ceramic capacitors should have C0G or NP0 dielectric. Avoid high-K dielectrics like Z5U and X7R. These and some other ceramics have piezoelectric properties that convert mechanical vibration into voltage noise that interferes with VCXO operation. For larger loop capacitor values such as 0.1 F or 1 F, PPS film types made by Panasonic, or metal poly types made by Murata or Cornell Dubilier are recommended. 625 x I CP x C 1 Damping Factor = R Z x ---------------------------------------N Where: RZ = Value of resistor in loop filter (Ohms) ICP = Charge pump current (amps) (refer to Charge Pump Current Table, below) N = Crystal multiplier shown in the above table C1 = Value of capacitor C1 in loop filter (Farads) As a general rule, the following relationship should be maintained between components C1 and C2 in the loop filter: For questions or changes regarding loop filter characteristics, please contact your sales area FAE, or ICS MicroClock Applications. Series Termination Resistor Clock output traces over one inch should use series termination. To series terminate a 50 trace (a commonly used trace impedance), place a 33 resistor in series with the clock line, as close to the clock output pin as possible. The nominal impedance of the clock output is 20. (The optional series termination resistor is not shown in the External Component Schematic.) C C2 1 = ------ Decoupling Capacitors 20 As with any high performance mixed-signal IC, the MK2059-01 must be isolated from system power supply noise to perform optimally. Charge Pump Current Table RSET Charge Pump Current (ICP) 1.4 M 680 k 10 A 20 A 540 k 120 k 25 A 100 A Decoupling capacitors of 0.01F must be connected between each VDD and the PCB ground plane. To further guard against interfering system supply noise, the MK2059-01 should use one common connection to the PCB power plane as shown in the diagram on the next page. The ferrite bead and bulk capacitor help reduce lower frequency noise in the supply that can lead to output clock phase modulation. Special considerations must be made in choosing loop components C1 and C2: MDS 2059-01 B 5 Revision 071001 Integrated Circuit Systems, Inc. 525 Race Street, San Jose, CA 95126 tel (408) 295-9800 www.icst.com MK2059-01 VCXO-Based Frame Clock Frequency Translator Recommended Power Supply Connection for Optimal Device Performance V D D P in C onnection to 3.3V P ow er P lane Ferrite B ead B ulk D ecoupling C apacitor (such as 1 F Tantalum ) V D D P in V D D P in 2) The loop filter components must also be placed close to the CHGP and VIN pins. C2 should be closest to the device. Coupling of noise from other system signal traces should be minimized by keeping traces short and away from active signal traces. Use of vias should be avoided. 3) The external crystal should be mounted just next to the device with short traces. The X1 and X2 traces should not be routed next to each other with minimum spaces, instead they should be separated and away from other traces. 0.01 F D ecoupling C apacitors 4) To minimize EMI the 33 series termination resistor, if needed, should be placed close to the clock output. Crystal Load Capacitors The device crystal connections should include pads for small capacitors from X1 to ground and from X2 to ground, shown as CL in the External Component Schematic. These capacitors are used to adjust the stray capacitance of the board to match the nominally required crystal load capacitance. Because load capacitance can only be increased in this trimming process, it is important to keep stray capacitance to a minimum by using very short PCB traces (and no via's) been the crystal and device. In most cases the load capacitors will not be required. They should not be stuffed on the prototype evaluation board as the indiscriminate use of these trim capacitors will typically cause more crystal centering error than their absence. If the need for the load capacitors is later determined, the values will fall within the 1-4 pf range. The need for, and value of, these trim capacitors can only be determined at prototype evaluation. Please refer to the Optimization of Crystal Load Capacitors section for more information. PCB Layout Recommendations For optimum device performance and lowest output phase noise, the following guidelines should be observed. Please also refer to the Recommended PCB Layout drawing on Page 7. 1) Each 0.01F decoupling capacitor should be mounted on the component side of the board as close to the VDD pin as possible. No via's should be used between decoupling capacitor and VDD pin. The PCB trace to VDD pin should be kept as short as possible, MDS 2059-01 B as should the PCB trace to the ground via. Distance of the ferrite bead and bulk decoupling from the device is less critical. 6 5) An optimum layout is one with all components on the same side of the board, minimizing vias through other signal layers (the ferrite bead and bulk decoupling capacitor can be mounted on the back). Other signal traces should be routed away from the MK2059-01. This includes signal traces just underneath the device, or on layers adjacent to the ground plane layer used by the device. The ICS Applications Note MAN05 may also be referenced for additional suggestions on layout of the crystal section. Optimization of Crystal Load Capacitors The concept behind the optional crystal load capacitors was introduced previously in this data sheet (see Crystal Load Capacitor section on Page 5). To determine the need for and value of these capacitors, you will need a PCB of your final layout, a frequency counter capable of less than 10 ppm resolution and accuracy, two power supplies, and some samples of the crystals which you plan to use in production, along with measured initial accuracy for each crystal at the specified crystal load capacitance, CL. To determine the value of the crystal capacitors: 1. Connect VDD to 3.3V. Connect pin 5 to the second power supply. Adjust the voltage on pin 5 to 0V. Measure and record the frequency of the CLK output. Revision 071001 Integrated Circuit Systems, Inc. 525 Race Street, San Jose, CA 95126 tel (408) 295-9800 www.icst.com MK2059-01 VCXO-Based Frame Clock Frequency Translator much stray capacitance and will need to be redone with a new layout to reduce stray capacitance. Alternately, the crystal may be re-specified for a higher lower load capacitance. Contact ICS MicroClock for details. If the centering error is more than 15 ppm positive, add identical fixed centering capacitors from each crystal pin to ground. The value for each of these caps (in pF) is given by: 2. Adjust the voltage on pin 5 to 3.3V. Measure and record the frequency of the same output. To calculate the centering error: 6 ( f 3.0V - f t arg et ) + ( f 0V - f t arg et ) Error = 10 x ------------------------------------------------------------------------------ - error xtal f t arg et External Capacitor = Where: 2 x (centering error)/(trim sensitivity) ftarget = nominal crystal frequency Trim sensitivity is a parameter which can be supplied by your crystal vendor. If you do not know the value, assume it is 30 ppm/pF. After any changes, repeat the measurement to verify that the remaining error is acceptably low (less than 15ppm). errorxtal =actual initial accuracy (in ppm) of the crystal being measured If the centering error is less than 15 ppm, adjustment is not needed for most applications. If the centering error is more than 15 ppm negative, the PCB has too Recommended PCB Layout F or m in im u m ou tp ut clock jitte r, rem ove g ro un d an d p ow er pla ne w ithin this en tire a re a. A lso rou te a ll othe r traces aw a y from th is a re a. G F or m in im u m ou tp ut clock jitte r, d evice V D D con ne ctio ns sho uld b e m a de to co m m on bulk d eco up ling d evice (see te xt). G G G G 1 2 3 4 5 6 7 8 9 10 G G G G 20 19 18 17 16 15 14 13 12 11 NC L eg en d: G MDS 2059-01 B G 7 = G ro un d C o nn ectio n Revision 071001 Integrated Circuit Systems, Inc. 525 Race Street, San Jose, CA 95126 tel (408) 295-9800 www.icst.com MK2059-01 VCXO-Based Frame Clock Frequency Translator Absolute Maximum Ratings Stresses above the ratings listed below can cause permanent damage to the MK2059-01. These ratings, which are standard values for ICS commercially rated parts, are stress ratings only. Functional operation of the device at these or any other conditions above those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods can affect product reliability. Electrical parameters are guaranteed only over the recommended operating temperature range. Item Rating Supply Voltage, VDD 7V All Inputs and Outputs -0.5V to VDD+0.5V Ambient Operating Temperature -40 to +85C Storage Temperature -65 to +150C Junction Temperature 175C Soldering Temperature 260C Recommended Operation Conditions Parameter Ambient Operating Temperature Power Supply Voltage (measured in respect to GND) Min. Typ. Max. Units -40 - +85 C +3.15 +3.3 +3.45 V DC Electrical Characteristics Unless stated otherwise, VDD = 3.3V 5%, Ambient Temperature -40 to +85C Parameter Symbol Conditions Min. Typ. Max. Units 3.15 3.3 3.45 V 10 15 mA Operating Voltage VDD Supply Current IDD Clock outputs unloaded, VDD = 3.3V Input High Voltage, SEL2 VIH - VDD-0.5 - - V Input Low Voltage, SEL2 VIL - - - 0.5 V Input High Voltage, ISEL, SEL1:0 VIH - 2 - - V Input Low Voltage, ISEL, SEL1:0 VIL - - - 0.8 V Input High Voltage, ICLK1, 2 VIH - VDD/2+1 - - V Input Low Voltage, ICLK1, 2 VIL - - - VDD/2-1 V Input High Current IIH VIH = VDD -10 - +10 A Input Low Current IIL VIL = 0 -10 - +10 A Input Capacitance, except X1 CIN - 7 - pF MDS 2059-01 B - 8 Revision 071001 Integrated Circuit Systems, Inc. 525 Race Street, San Jose, CA 95126 tel (408) 295-9800 www.icst.com MK2059-01 VCXO-Based Frame Clock Frequency Translator Parameter Symbol Conditions Min. Typ. Max. Units Output High Voltage (CMOS Level) VOH IOH = -4 mA VDD-0.4 V Output High Voltage VOH IOH = -8 mA 2.4 V Output Low Voltage VOL IOL = 8 mA - Short Circuit Current IOS VIN, VCXO Control Voltage VXC Nominal Output Impedance ZOUT - 0.4 50 0 V mA VDD V 20 AC Electrical Characteristics Unless stated otherwise, VDD = 3.3V 5%, Ambient Temperature -40 to +85 C Parameter Symbol VCXO Crystal Pull Range fXP VCXO Crystal Nominal Frequency fX Input Jitter Tolerance tji Input pulse width (1) tpi Conditions Using Recommended Crystal Min. Typ. Max. Units -115 +115 ppm 13.5 27 MHz 0.4 UI In reference to input clock period 10 ns FOUT ICLK = 0 ppm error 0 0 0 ppm Output Duty Cycle (% high time) tOD Measured at VDD/2, CL=15pF 40 - 60 % Output Rise Time tOR 0.8 to 2.0V, CL=15pF 1.5 ns Output Fall Time tOF 2.0 to 0.8V, CL=15pF 1.5 ns Skew, Input to Output Clock tIO Rising edges, CL=15pF +5 ns Cycle Jitter (short term jitter) tja Timing Jitter, Filtered 500Hz-1.3MHz (OC-3) tjf Timing Jitter, Filtered 65kHz-1.3MHz (OC-3) tjf Output Frequency Error -5 150 ps p-p Referenced to Mitel/Zarlink MT9045, Note 2 227 ps p-p Referenced to Mitel/Zarlink MT9045, Note 2 170 ps p-p Note 1: Minimum high or low time of input clock. Note 2: Input reference is the 8 kHz output from a Mitel/Zarlink MT9045 device in freerun mode (SEL2:0 = 100, 19.44 MHz external crystal). MDS 2059-01 B 9 Revision 071001 Integrated Circuit Systems, Inc. 525 Race Street, San Jose, CA 95126 tel (408) 295-9800 www.icst.com MK2059-01 VCXO-Based Frame Clock Frequency Translator Package Outline and Package Dimensions (20 pin SOIC, 300 Mil. Wide Body) Package dimensions are kept current with JEDEC Publication No. 95 Millimeters Symbol A A1 A2 B C D E e H h L Index A rea E H 1 2 Min Inches Max -2.65 1.10 -2.05 2.55 0.33 0.51 0.18 0.32 12.60 13.00 7.40 7.60 1.27 Basic 10.00 10.65 0.25 0.75 0.40 1.27 0 8 Min Max -0.104 0.0040 -0.081 0.100 0.013 0.020 0.007 0.013 0.496 0.512 0.291 0.299 0.050 Basic 0.394 0.419 0.010 0.029 0.016 0.050 0 8 h x 45 o D A2 A A1 e L C B Ordering Information Part / Order Number Marking Shipping packaging Package Temperature MK2059-01SI MK2059-01SI Tubes 20 pin SOIC -40 to +85 C MK2059-01SITR MK2059-01SI Tape and Reel 20 pin SOIC -40 to +85 C While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems (ICS) assumes no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are not recommended without additional processing by ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS does not authorize or warrant any ICS product for use in life support devices or critical medical instruments. MDS 2059-01 B 10 Revision 071001 Integrated Circuit Systems, Inc. 525 Race Street, San Jose, CA 95126 tel (408) 295-9800 www.icst.com