ICS843004I-04 FEMTOCLOCKS CRYSTAL/LVCMOS-TO- 3.3V LVPECL FREQUENCY SYNTHESIZER

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1 GENERAL DESCRIPTION The is a 4 output LVPECL ICS Synthesizer optimized to generate clock HiPerClockS frequencies for a variety of high performance applications and is a member of the HiPerClocks TM family of high performance clock solutions from ICS. This device can select its input reference clock from either a crystal input or a singleended clock signal. It can be configured to generate 4 outputs with individually selectable divide-by-one or divide-by-four function via the 4 frequency select pins (F_SEL[3:0]). The uses ICS 3 rd generation low phase noise VCO technology and can achieve ps or lower typical rms phase jitter. This ensures that it will easily meet clocking requirements for SDH (STM-/STM-4/STM-6) and SONET (OC-3/ OC2/OC-48). This device is suitable for multi-rate and multiple port line card applications. The is conveniently packaged in a small 24-pin TSSOP package. FEATURES Four LVPECL outputs Selectable crystal oscillator interface or LVCMOS/LVTTL single-ended input Supports the following applications: SONET/SDH, SATA, or 0Gb Ethernet Output frequency range: 40MHz - 70MHz, 560MHz - 680MHz VCO range: 560MHz - 680MHz Crystal oscillator and CLK range: 7.5MHz MHz RMS phase MHz output, using a 9.44MHz crystal (2kHz - 20MHz): 0.82ps (typical) RMS phase 56.25MHz output, using a MHz crystal (.875MHz - 20MHz): 0.57ps (typical) RMS phase 55.52MHz output, using a 9.44MHz crystal (2kHz - 20MHz): 0.94ps (typical) Full 3.3V supply mode -40 C to 85 C ambient operating temperature Available in both standard and lead-free RoHS compliant packages BLOCK DIAGRAM PIN ASSIGNMENT XTAL_IN OSC XTAL_OUT Pulldown CLK INPUT_SEL Pulldown Pulldown MR Pullup F_SEL0 Pullup F_SEL Pullup F_SEL2 0 Phase Detector M = 32 VCO Q0 nq0 Q nq Q2 nq2 nq Q VCCo Q0 nq0 MR F_SEL3 nc VCCA F_SEL0 VCC nq2 Q2 VCCO Q3 nq3 VEE F_SEL2 INPUT_SEL CLK VEE XTAL_IN F_SEL XTAL_OUT 24-Lead TSSOP 4.40mm x 7.8mm x 0.92mm package body G Package Top View 0 Q3 nq3 Pullup F_SEL3

2 TABLE. PIN DESCRIPTIONS Number Name, 2 nq, Q 3, 22 O 4, 5 Q0, nq0 6 MR 7, 0, 2, 8 F_SEL3, F_SEL0, F_SEL, F_SEL2 8 nc 9 A XTAL_OUT, 3, 4 XTAL_IN 5, 9 V EE 6 CLK 7 INPUT_SEL 20, 2 nq3, Q3 23, 24 Q2, nq2 NOTE: Pulldown and Pullup Type Description O utput Differential output pair. LVPECL interface levels. P ower Output supply pins. O uput Differential output pair. LVPECL interface levels. Active HIGH Master Reset. When logic HIGH, the Pulldown internal dividers are reset causing the true outputs Qx to go low and the inverted outputs nqx to go high. When logic LOW, the internal dividers and the outputs are enabled. LVCMOS/LVTTL interface levels. P ullup Frequency select pins. LVCMOS/LVTTL interface levels. See Table 3. U nused No connect. P ower Analog supply pin. P ower Core supply pin. Parallel resonant XTAL_IN is the input. P ower Negative supply pins. crystal P ulldown LVCMOS/LVTTL clock input. interface. XTAL_OUT is the output, Selects between crystal or CLK inputs as the the PLL Reference source. Pulldown Selects XTAL inputs when LOW. LVCMOS/LVTTL interface levels. Selects CLK when HIGH. O utput Differential output pair. LVPECL interface levels. O utput Differential output pair. LVPECL interface levels. refer to internal input resistors. See Table 2, Pin Characteristics, for typical values. TABLE 2. PIN CHARACTERISTICS Symbol C IN R R PULLDOWN PULLUP Parameter Test Conditions Minimum Typical Maximum Capacitance 4 pf Pulldown Resistor 5 kω Pullup Resistor 5 kω Units TABLE 3. OUTPUT CONFIGURATION AND FREQUENCY RANGE FUNCTION TABLE s VCO Output Frequency (MHz) Divider Value F _SELx XTAL (MHz) (MHz) Q0/nQ0:Q3/nQ Application SONET/SDH SATA 0 Gigabit Ethernet Gigabit Ethernet B/64B FEC 2

3 ABSOLUTE MAXIMUM RATINGS Supply Voltage, 4.6V s, V I -0.5V to + 0.5V Outputs, I O Continuous Current 50mA Surge Current 00mA Package Thermal Impedance, θ JA 70 C/W (0 mps) Storage Temperature, T STG -65 C to 50 C NOTE: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These ratings are stress specifications only. Functional operation of product at these conditions or any conditions beyond those listed in the DC Characteristics or AC Characteristics is not implied. Exposure to absolute maximum rating conditions for extended periods may affect product reliability. TABLE 4A. POWER SUPPLY DC CHARACTERISTICS, = A = O = 3.3V±5%, TA = -40 C TO 85 C Symbol V V C CA C I EE I I C CO CA C CO Parameter Test Conditions Minimum Typical Maximum Units Core Supply Voltage V Analog Supply Voltage V Output Supply Voltage V Power Supply Current 20 ma Analog Supply Current 0 ma Output Supply Current 20 ma TABLE 4B. LVCMOS / LVTTL DC CHARACTERISTICS, = A = O = 3.3V±5%, TA = -40 C TO 85 C Symbol V IH V IL I IH I IL Parameter nput High Voltage nput Low Voltage Test Conditions Minimum Typical Maximum C I 2 V C + V I V High Current Low Current CLK, MR, INPUT_SEL F_SEL0:F_SEL3 CLK, MR, INPUT_SEL F_SEL0:F_SEL3 = V N = V N I Units = 50 µ A I = 3.465V, VIN = 5 µ A = 0V -5 µ A = 3.465V, V = 0V -50 µ A IN TABLE 4C. LVPECL DC CHARACTERISTICS, = A = O = 3.3V±5%, TA = -40 C TO 85 C Symbol Parameter utput High Voltage; NOTE utput Low Voltage; NOTE eak-to-peak Output Voltage Outputs terminated with 50 to V OH V OL Test Conditions Minimum CC. 4 CC Typical Maximum CC 0. 9 CC. 7. O V O - V O - V O V O - V O - V VSWING P Swing V NOTE : Ω V - 2V. C CO Units 3

4 TABLE 5. CRYSTAL CHARACTERISTICS Parameter Mode of Oscillation Test Conditions Minimum Typical Fundamental Maximum Frequency MHz Equivalent Series Resistance (ESR) 50 Ω Shunt Capacitance 7 pf Drive Level mw NOTE: Characterized using an 8pF parallel resonant crystal. Units TABLE 6. AC CHARACTERISTICS, = A = O = 3.3V±5%, TA = -40 C TO 85 C Symbol f OUT Parameter Output Frequency Test Conditions Minimum Typical Maximum Units Output Divider = MHz Output Divider = MHz t sk(o) Output Skew; NOTE, 2, 3 75 ps 55.52MHz, Integration Range: 2kHz - 20MHz 0.94 ps t jit(ø) RMS Phase Jitter (Random); 56.25MHz, NOTE 4 Integration Range:.875MHz - 20MHz 0.57 ps MHz, Integration Range: 2kHz - 20MHz 82 ps / tf O utput Rise/Fall Time 20% to 80% ps t R odc Output Duty Cycle Output Divider = % Output Divider = % NOTE : Defined as skew between outputs at the same supply voltages and with equal load conditions. Measured at V /2. C CO NOTE 2: This parameter is defined in accordance with JEDEC Standard 65. NOTE 3: Output skew measurements taken with all outputs in the same divide configuration. NOTE 4: Please refer to the Phase Noise Plot. 4

5 PARAMETER MEASUREMENT INFORMATION 2V A = 2V nqx, O Qx SCOPE Qx nqy LVPECL V EE nqx Qy tsk(o) -.3V±0.65V 3.3V CORE/3.3V OUTPUT LOAD AC TEST CIRCUIT OUTPUT SKEW Phase Noise Plot Noise Power Phase Noise Mask 80% 80% V SWING Offset Frequency f f 2 Clock Outputs 20% t R t F 20% RMS Jitter = Area Under the Masked Phase Noise Plot RMS PHASE JITTER OUTPUT RISE/FALL TIME nq0:nq3 Q0:Q3 t PW t PERIOD t PW odc = x 00% t PERIOD OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD 5

6 APPLICATION INFORMATION POWER SUPPLY FILTERING TECHNIQUES As in any high speed analog circuitry, the power supply pins are vulnerable to random noise. The provides separate power supplies to isolate any high switching noise from the outputs to the internal PLL., A, and V DDO should be individually connected to the power supply plane through vias, and bypass capacitors should be used for each pin. To achieve optimum jitter performance, power supply isolation is required. Figure illustrates how a 0Ω resistor along with a 0µF and a.0μf bypass capacitor should be connected to each A. A 3.3V.0μF 0Ω.0μF 0μF FIGURE. POWER SUPPLY FILTERING CRYSTAL INPUT INTERFACE The has been characterized with 8pF parallel resonant crystals. The capacitor values shown in Figure 2 below were determined using a 9.44MHz, 8pF parallel resonant crystal and were chosen to minimize the ppm error. C 22p XTAL_OUT X 8pF Parallel Crystal C2 22p XTAL_IN Figure 2. CRYSTAL INPUt INTERFACE 6

7 LVCMOS TO XTAL INTERFACE The XTAL_IN input can accept a single-ended LVCMOS signal through an AC couple capacitor. A general interface diagram is shown in Figure 3. The XTAL_OUT pin can be left floating. The input edge rate can be as slow as 0ns. For LVCMOS inputs, it is recommended that the amplitude be reduced from full swing to half swing in order to prevent signal interference with the power rail and to reduce noise. This configuration requires that the output impedance of the driver (Ro) plus the series resistance (Rs) equals the transmission line impedance. In addition, matched termination at the crystal input will attenuate the signal in half. This can be done in one of two ways. First, R and R2 in parallel should equal the transmission line impedance. For most 50Ω applications, R and R2 can be 00Ω. This can also be accomplished by removing R and making R2 50Ω. VDD VDD R Ro Rs Zo = 50.uf XTAL_IN Zo = Ro + Rs R2 XTAL_OUT FIGURE 3. GENERAL DIAGRAM FOR LVCMOS DRIVER TO XTAL INPUT INTERFACE RECOMMENDATIONS FOR UNUSED INPUT AND OUTPUT PINS INPUTS: OUTPUTS: CRYSTAL INPUT: For applications not requiring the use of the crystal oscillator input, both XTAL_IN and XTAL_OUT can be left floating. Though not required, but for additional protection, a kω resistor can be tied from XTAL_IN to ground. CLK INPUT: For applications not requiring the use of a clock input, it can be left floating. Though not required, but for additional protection, a kω resistor can be tied from the CLK input to ground. LVCMOS CONTROL PINS: All control pins have internal pull-ups or pull-downs; additional resistance is not required but can be added for additional protection. A kω resistor can be used. LVPECL OUTPUT All unused LVPECL outputs can be left floating. We recommend that there is no trace attached. Both sides of the differential output pair should either be left floating or terminated. 7

8 TERMINATION FOR 3.3V LVPECL OUTPUT The clock layout topology shown below is a typical termination for LVPECL outputs. The two different layouts mentioned are recommended only as guidelines. FOUT and nfout are low impedance follower outputs that generate ECL/LVPECL compatible outputs. Therefore, terminating resistors (DC current path to ground) or current sources must be used for functionality. These outputs are designed to drive 50Ω transmission lines. Matched impedance techniques should be used to maximize operating frequency and minimize signal distortion. Figures 4A and 4B show two different layouts which are recommended only as guidelines. Other suitable clock layouts may exist and it would be recommended that the board designers simulate to guarantee compatibility across all printed circuit and clock component process variations. Z o = 50Ω 25Ω 3.3V 25Ω FOUT FIN Z o = 50Ω Z o = 50Ω 50Ω 50Ω FOUT FIN RTT = ((V OH + V OL ) / ( 2)) 2 Z o RTT - 2V Z o = 50Ω 84Ω 84Ω FIGURE 4A. LVPECL OUTPUT TERMINATION FIGURE 4B. LVPECL OUTPUT TERMINATION 8

9 SCHEMATIC EXAMPLE Figure 5 shows a schematic example for. In this example, the input is a 9.44MHz parallel resonant crystal with load capacitor CL=8pF. The 22pF frequency fine tuning capacitors are used C and C2. This example also shows general logic control input handling. For decoupling capacitors, it is recommended to have one decouple capacitor per power pin. Each decoupling capacitor should be located as close as possible to the power pin. The low pass filter R2, C3 and C4 should also be located as close to the A pin as possible. MR VCC F_SEL3 VCCA R2 0 C3 0uF C4 0.0u VCCO Zo = 50 Ohm R V R5 33 Logic Control Examples VCC F_SEL0 + VDD RU K Set Logic to '' To Logic pins RD Not Install VDD Set Logic to '0' RU2 Not Install RD2 K To Logic pins F_SEL 2 0 F_SEL VCC F_SEL0 VCCA NC F_SEL3 MR nq0 Q0 VCCO Q nq XTAL_OUT XTAL_IN VEE CLK INPUT_SEL F_SEL2 VEE nq3 Q3 VCCO Q2 nq U i-04 VCC=3.3V VCCO=3.3V Zo = 50 Ohm R R (U-3) VCC (U-) (U-22) Zo = 50 Ohm C 0.uF C2 0.uF VCC C3 0.uF C2 22pF X 9.44MHz 8pF C 22pF VCCO Zo = 50 Ohm R5 50 R Q Ro ~ 7 Ohm R8 Zo = 50 Ohm Optional Y-Termination R Driver_LVCMOS INPUT_SEL F_SEL2 FIGURE 5. ICS844004I-04 SCHEMATIC EXAMPLE 9

10 POWER CONSIDERATIONS This section provides information on power dissipation and junction temperature for the. Equations and example calculations are also provided.. Power Dissipation. The total power dissipation for the is the sum of the core power plus the power dissipated in the load(s). The following is the power dissipation for = 3.3V + 5% = 3.465V, which gives worst case results. NOTE: Please refer to Section 3 for details on calculating power dissipated in the load. Power (core) MAX = _MAX * I EE_MAX = 3.465V * 20mA = 45.8mW Power (outputs) MAX = 30.2mW/Loaded Output pair If all outputs are loaded, the total power is 4 * 30mW = 20mW Total Power _MAX (3.465V, with all outputs switching) = mW = 535.8mW 2. Junction Temperature. Junction temperature, Tj, is the temperature at the junction of the bond wire and bond pad and directly affects the reliability of the device. The maximum recommended junction temperature for HiPerClockS TM devices is 25 C. The equation for Tj is as follows: Tj = θ JA * Pd_total + T A Tj = Junction Temperature θ JA = Junction-to-Ambient Thermal Resistance Pd_total = Total Device Power Dissipation (example calculation is in section above) T A = Ambient Temperature In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance θ JA must be used. Assuming an air flow of meter per second and a multi-layer board, the appropriate value is 65 C/W per Table 7 below. Therefore, Tj for an ambient temperature of 85 C with all outputs switching is: 85 C W * 65 C/W = 9.8 C. This is below the limit of 25 C. This calculation is only an example. Tj will obviously vary depending on the number of loaded outputs, supply voltage, air flow, and the type of board (single layer or multi-layer). TABLE 7. THERMAL RESISTANCE θ JA FOR 24-LEAD TSSOP, FORCED CONVECTION θ JA by Velocity (Meters per Second) Multi-Layer PCB, JEDEC Standard Test Boards 70 C/W 65 C/W 62 C/W 0

11 3. Calculations and Equations. The purpose of this section is to derive the power dissipated into the load. LVPECL output driver circuit and termination are shown in the Figure 6. O Q V OUT RL 50 O - 2V FIGURE 6. LVPECL DRIVER CIRCUIT AND TERMINATION To calculate worst case power dissipation into the load, use the following equations which assume a 50Ω load, and a termination voltage of V - 2V. CC For logic high, V OUT = V OH_MAX = V CC_MAX 0.9V (V CC_MAX - V OH_MAX ) = 0.9V For logic low, V OUT = V OL_MAX = V CC_MAX.7V (V CC_MAX - V OL_MAX ) =.7V Pd_H is power dissipation when the output drives high. Pd_L is the power dissipation when the output drives low. Pd_H = [(V (V - 2V))/R OH_MAX CC_MAX [(2V - 0.9V)/50Ω] * 0.9V = 9.8mW Pd_L = [(V (V - 2V))/R OL_MAX CC_MAX [(2V -.7V)/50Ω] *.7V = 0.2mW L] * (V CC_MAX L] * (V CC_MAX - V ) = [(2V - (V - V ))/R * (V - V ) = OH_MAX CC _MAX OH_MAX L] CC_MAX OH_MAX - V ) = [(2V - (V - V ))/R * (V - V ) = OL_MAX CC _MAX OL_MAX L] CC_MAX OL_MAX Total Power Dissipation per output pair = Pd_H + Pd_L = 30mW

12 RELIABILITY INFORMATION TABLE 8. θ JA VS. AIR FLOW TABLE FOR 24 LEAD TSSOP θ JA by Velocity (Meters per Second) Multi-Layer PCB, JEDEC Standard Test Boards 70 C/W 65 C/W 62 C/W TRANSISTOR COUNT The transistor count for is:

13 PACKAGE OUTLINE - G SUFFIX FOR 24 LEAD TSSOP TABLE 9. PACKAGE DIMENSIONS SYMBOL Minimum Millimeters N 24 Maximum A A A b c D E 6.40 BASIC E e 0.65 BASIC L α 0 8 aaa Reference Document: JEDEC Publication 95, MO-53 3

14 TABLE 0. ORDERING INFORMATION Part/Order Number Marking ICS843004AGI-04 ICS843004AI04 ICS843004AGI-04T ICS843004AI04 ICS843004AGI-04LF ICS843004AGI-04LFT NOTE: Parts ICS43004AI04L ICS43004AI04L Package Shipping Packaging 24 Lead TSSOP tube Temperature -40 C to 85 C 24 Lead TSSOP 2500 tape & reel -40 C to 85 C 24 Lead "Lead-Free" TSSOP tube -40 C to 85 C 24 Lead "Lead-Free" TSSOP 2500 tape & reel -40 C to 85 C that are ordered with an "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant. The aforementioned trademarks, HiPerClockS and FEMTOCLOCKS are trademarks of Integrated or its subsidiaries in the United States and/or other countries. While the information presented herein has been checked for both accuracy and reliability, Integrated Systems, Incorporated (ICS) assumes no responsibility for either its use or for 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 and industrial applications. Any other applications such as those requiring 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. 4