SL2305 Low Jitter and Skew 10 to 140 MHz Zero Delay Buffer (ZDB) Key Features x x x x x x x x x x x 10 to 140 MHz operating frequency range Low output clock jitter: 45 ps-typ cycle-to-cycle jitter Low output-to-output skew: 50 ps-typ Low product-to-product skew: 125 ps-typ 3.3 V power supply range Low power dissipation: 26 mA-max at 66 MHz 42 mA-max at 140 MHz One input drives 5 outputs organized as 4+1 SpreadThru™ PLL that allows use of SSCG Standard and High-Drive options Available in 8-pin SOIC and TSSOP packages Available in Commercial and Industrial grades Applications x x x x x x Printers and MFPs Digital Copiers PCs and Work Stations DTV Routers, Switchers and Servers Digital Embeded Systems Description The SL2305 is a low skew, low jitter and low power Zero Delay Buffer (ZDB) designed to produce up to five (5) clock outputs from one (1) reference input clock for high speed clock distribution applications. The product has an on-chip PLL which locks to the input clock at CLKIN and receives its feedback internally from the CLKOUT pin. The SL2305 is available with two (2) drive strength versions. The -1 is the standard-drive version and -1H is the highdrive version. The SL2305 high-drive version operates up to 140MHz and the standard drive version -1 operates up to 100. The SL2305 enter into Power-Down (PD) mode if the input at CLKIN is DC (0 to VDD). In this power-down state all five (5) outputs are tri-stated and the PLL is turned off leading to less than 12ȝA-max of power supply current draw. Benefits x x x x x Up to five (5) distribution of input clock Standard and High-Dirive levels to control impedance level, frequency range and EMI Low jitter and skew Low power dissipation Low cost Block Diagram Rev 1.4, May 25, 2007 Page 1 of 11 2200 Laurelwood Road, Santa Clara, CA 95054 Tel: (408) 855-0555 Fax: (408) 855-0550 www.SpectraLinear.com SL2305 Pin Configuration 8-Pin SOIC or TSSOP Pin Description Pin Number Pin Name Pin Type Pin Description 1 CLKIN Input 2 CLK2 Output Buffered Clock Output Weak pull-down (250kȍ). 3 CLK1 Output Buffered Clock Output. Weak pull-down (250kȍ). 4 GND Power Power Ground. 5 CLK3 Output Buffered Clock Output. Weak pull-down (250kȍ). 6 VDD Power 3.3V Power Supply. 7 CLK4 Output Buffered Clock Output. Weak pull-down (250kȍ). 8 CLKOUT Output Buffered Clock Output, Used for Internal Feedback to PLL Input. Weak pulldown (250kȍ). Rev 1.4, May 25, 2007 Reference Frequency Clock Input. Weak pull-down (250kȍ). Page 2 of 11 SL2305 General Description High and Low-Drive Product Options The SL2305 is a low skew, low jitter Zero Delay Buffer with very low operating current. The SL2305 is offered with High-Drive “-1H” and StandardDrive “-1” options. These drive options enable the users to control load levels, frequency range and EMI control. Refer to the AC electrical tables for the details. The product includes an on-chip high performance PLL that locks into the input reference clock and produces nine (9) output clock drivers tracking the input reference clock for systems requiring clock distribution. Skew and Zero Delay In addition to CLKOUT that is used for internal PLL feedback, there is a single bank with four (4) outputs, bringing the number of total available output clocks to five (5). All outputs should drive the similar load to achieve outputto-output and input-to-output skew specifications given in the AC electrical tables. Input and output Frequency Range However, Zero delay between input and outputs can be adjusted by changing the loading of CLKOUT relative to the clock outputs since CLKOUT is the feedback to the PLL. The input and output frequency range is the same. But, the frequency range depends on the drive levels and load capacitance (CL) as given in the below Table 1. Drive CL(pF) Min(MHz) Max(MHz) HIGH 15 10 140 HIGH 30 10 100 STD 15 10 100 STD 30 10 66 Table 1. Input/Output Frequency Range If the input clock frequency is DC (0 to VDD), this is detected by an input detection circuitry and all nine (5) clock outputs are forced to Hi-Z. The PLL is shutdown to save power. In this shutdown state, the product draws less than 12ȝA-max supply current. SpreadThru™ Feature Power Supply Range (VDD) The SL2305 is designed to operate from 3.0V (Min) to 3.6V (Max), complying with VDD=3.3V+/-10% requirement. An internal on-chip voltage regulator is used to supply PLL constant power supply of 1.8V, leading to a consistent and stable PLL electrical performance in terms of skew, jitter and power dissipation. Refer to SL23EP05 for 2.5V and SL23EPL05 for 1.8V power supply operation requirements. Temperature Range and Packages The SL2305 is offered with extended commercial temperature range of 0 to +70°C (C-Grade) and industrial temperature range of -40 to +85°C (I-Grade). The SL2305 is available in 8-pin SOIC (150-mil) and TSSOP (173-mil) packages. If a Spread Spectrum Clock (SSC) were to be used as an input clock, the SL2305 is designed to pass the modulated Spread Spectrum Clock (SSC) signal from its CLKIN (reference) input to the output clocks. The same spread characteristics at the input are passed through the PLL and drivers without any degradation in spread percent (%), spread profile and modulation frequency. Rev 1.4, May 25, 2007 Page 3 of 11 SL2305 Absolute Maximum Ratings Description Condition Min Max Unit Supply voltage, VDD – 0.5 4.6 V All Inputs and Outputs – 0.5 VDD+0.5 V Ambient Operating Temperature In operation, C-Grade 0 85 °C Ambient Operating Temperature In operation, I-Grade – 40 85 °C Storage Temperature No power is applied – 65 150 °C Junction Temperature In operation, power is applied – 125 °C – 260 °C 2000 – V Soldering Temperature ESD Rating (Human Body Model) MIL-STD-883, Method 3015 Operating Conditions: Unless otherwise stated VDD=3.3V+/-10% and both C and I Grades Symbol Description Condition Min Max Unit VDD 3.3V Supply Voltage 3.3V+/-10% 3.0 3.6 V TA Operating Temperature(Ambient) Commercial 0 85 °C –40 85 °C 10 to 140 MHz, -1H high drive – 15 pF 10 to 100 MHz, -1H high drive – 30 pF 10 to 100MHz, -1 standard drive – 15 pF 10 to 66MHz, -1 standard drive – 30 pF – 7 pF 0.05 100 ms CLOAD Load Capacitance Industrial CIN Input Capacitance CLKIN pin tpu Power-up Time Power-up time for all VDDs to reach minimum VDD voltage (VDD=3.0V). CLBW Closed-loop bandwidth 3.3V, (typical) 1.2 MHz ZOUT Output Impedance 3.3V (typical), -1H high drive 22 3.3V (typical), -1 standard drive 32 Rev 1.4, May 25, 2007 Page 4 of 11 SL2305 DC Electrical Specifications: Unless otherwise stated VDD=3.3V+/-10% and both C and I Grades Symbol Description Condition Min Max Unit 3.0 3.6 V VDD Supply Voltage VIL Input LOW Voltage CLKIN (Pin-1) – 0.8 V VIH Input HIGH Voltage CLKIN (Pin-1) 2.0 VDD+0.3 V IIL Input LOW Current CLKIN, 0 < VIN < 0.8V – 25 µA IIH Input HIGH Current CLKIN, VIN = VDD – 50 µA VOL Output LOW Voltage (All outputs) IOL = 8 mA (standard drive) – 0.4 V IOL = 12 mA (high drive) – 0.4 V Output HIGH Voltage (All outputs) IOH = –8 mA (standard drive) 2.4 – V IOH = –12 mA (high drive) 2.4 – V Power Down Supply Current CLKIN=0 to VDD C-Grade, Power-down if CLKIN=0 to VDD or input is floating – 12 µA I-Grade, Power-down if CLKIN=0 to VDD or input is floating – 25 µA VOH IDDPD IDD1 Power Supply Current All Outputs CL=0, 33-MHz CLKIN – 18 mA IDD2 Power Supply Current All Outputs CL=0, 66-MHz CLKIN – 26 mA IDD3 Power Supply Current All Outputs CL=0, 100-MHz CLKIN – 34 mA IDD4 Power Supply Current All Outputs CL=0, 140-MHz CLKIN – 42 mA RPD Pull-down Resistors Pins-1/2/3/5/7/8, 250k-typ 175 325 k Rev 1.4, May 25, 2007 Page 5 of 11 SL2305 Switching Specifications: Unless otherwise stated VDD=3.3V+/-10% and both C and I Grades Symbol FMAX1 INDC Description Condition Maximum Frequency (Input=Output ) All Active PLL Modes [1] Input Duty Cycle [2] OUTDC Output Duty Cycle tr/f Rise, Fall Time (3.3V) (Measured at: 0.8 to 2.0V) [2] [2] 140 MHz High drive (-1H), All outputs CL=30pF 10 100 MHz Standard drive, (-1), All outputs CL=15pf 10 100 MHz Standard drive, (-1), All outputs CL=30pf 10 66 MHz Measured at 1.4V, Fout=66MHz, CL=15pF 30 70 % Measured at 14V, Fout=66MHz, CL=15pF 40 60 % High drive (-1H), CL=10pF – 1.5 ns High drive (-1H), CL=30pF – 1.8 ns Standard drive (-1), CL=10pF – 2.2 ns Standard drive (-1), CL=30pF – 2.5 ns All outputs CL=0 or equally loaded, -1 or -1H drives – 120 ps – 400 ps –150 150 ps Time from 90% of VDD to valid clocks on all the output clocks – 1.0 ms Fin=Fout=66 MHz, <CL=15pF, -1H drive – 90 ps Fin=Fout=66 MHz, <CL=15pF, -1 drive – 100 ps Fin=Fout=66 MHz, <CL=30pF, -1H drive – 120 ps Fin=Fout=66 MHz, <CL=30pF, -1 drive – 140 ps t2 Device-to-Device Skew (Measured at VDD/2) All outputs CL=0 or equally loaded, -1 or -1H drives t3 Delay Time, CLKIN Rising Edge to CLKOUT Rising [2] Edge Measured at VDD/2 [2] PLL Lock Time CCJ Cycle-to-cycle Jitter [2] Unit 10 Output-to-Output Skew (Measured at VDD/2) tPLOCK Max High drive (-1H). All outputs CL=15pF t1 [2] Min Notes: 1. For the given maximum loading conditions. See CL in Operating Conditions Table. 2. Parameter is guaranteed by design and characterization. Not 100% tested in production. Rev 1.4, May 25, 2007 Page 6 of 11 SL2305 External Components & Design Considerations Typical Application Schematic Comments and Recommendations Decoupling Capacitor: A decoupling capacitor of 0.1ȝF must be used between VDD and VSS on the pins 6 and 4. Place the capacitor on the component side of the PCB as close to the VDD pin as possible. The PCB trace to the VDD pin and to the GND via should be kept as short as possible. Do not use vias between the decoupling capacitor and the VDD pin. Series Termination Resistor: A series termination resistor is recommended if the distance between the outputs and the load is over 1 ½ inch. The nominal impedance of the Clock outputs are about 30 . Use 20 resistor in series with the output to terminate 50 trace impedance and place 20 resistor as close to the clock outputs as possible. Zero Delay and Skew Control: All outputs and CLKIN pins should be loaded with the same load to achieve “Zero Delay” between the CLKIN and the outputs. The CLKOUT pin is connected to CLKIN internally on-chip for internal feedback to PLL, and sees an additional 2 pF load with respect to the clock pins. For applications requiring zero input/output delay, the load at the all output pins including the CLKOUT pin must be the same. If any delay adjustment is required, the capacitance at the CLKOUT pin could be increased or decreased to increase or decrease the delay between clocks and CLKIN. For minimum pin-to-pin skew, the external load at the clock outputs must be the same. Rev 1.4, May 25, 2007 Page 7 of 11 SL2305 Switching Waveforms Figure 1. Output to Output Skew Figure 2. Input- to-Output Skew Figure 3. Part-to-Part Skew Rev 1.4, May 25, 2007 Page 8 of 11 SL2305 Package Outline and Package Dimensions 8-Pin SOIC Package (150 mil) Thermal Characteristics Parameter Thermal Resistance Junction to Ambient Thermal Resistance Junction to Case Rev 1.4, May 25, 2007 Symbol Condition Min Typ Max Unit ș JA Still air - 150 - °C/W ș JA 1m/s air flow - 140 - °C/W ș JA 3m/s air flow - 120 - °C/W ș JC Independent of air flow - 40 - °C/W Page 9 of 11 SL2305 Package Outline and Package Dimensions 8-Pin TSSOP Package (173 mil) Thermal Characteristics Parameter Thermal Resistance Junction to Ambient Thermal Resistance Junction to Case Rev 1.4, May 25, 2007 Symbol Condition Min Typ Max Unit Still air - 110 - °C/W 1m/s air flow - 100 - °C/W 3m/s air flow - 80 - °C/W Independent of air flow - 35 - °C/W Page 10 of 11 SL2305 Ordering Information [3] Ordering Number Marking Shipping Package Package Temperature SL2305SC-1 SL2305SC-1 Tube 8-pin SOIC 0 to 70°C SL2305SC-1T SL2305SC-1 Tape and Reel 8-pin SOIC 0 to 70°C SL2305SI-1 SL2305SI-1 Tube 8-pin SOIC -40 to 85°C SL2305SI-1T SL2305SI-1 Tape and Reel 8-pin SOIC -40 to 85°C SL2305SC-1H SL2305SC-1H Tube 8-pin SOIC 0 to 70°C SL2305SC-1HT SL2305SC-1H Tape and Reel 8-pin SOIC 0 to 70°C SL2305SI-1H SL2305SI-1H Tube 8-pin SOIC -40 to 85°C SL2305SI-1HT SL2305SI-1H Tape and Reel 8-pin SOIC -40 to 85°C SL2305ZC-1 SL2305ZC-1 Tube 8-pin TSSOP 0 to 70°C SL2305ZC-1T SL2305ZC-1 Tape and Reel 8-pin TSSOP 0 to 70°C SL2305ZI-1 SL2305ZI-1 Tube 8-pin TSSOP -40 to 85°C SL2305ZI-1T SL2305ZI-1 Tape and Reel 8-pin TSSOP -40 to 85°C SL2305ZC-1H SL2305ZC-1H Tube 8-pin TSSOP 0 to 70°C SL2305ZC-1HT SL2305ZC-1H Tape and Reel 8-pin TSSOP 0 to 70°C SL2305ZI-1H SL2305ZI-1H Tube 8-pin TSSOP -40 to 85°C SL2305ZI-1HT SL2305ZI-1H Tape and Reel 8-pin TSSOP -40 to 85°C Notes: 3. The SL2305 products are RoHS compliant. While SLI has reviewed all information herein for accuracy and reliability, Spectra Linear Inc. assumes no responsibility for the use of any circuitry or for the infringement of any patents or other rights of third parties which would result from each use. This product is intended for use in normal commercial applications and is not warranted not is it intended for use in life support, critical medical instruments, or any other application requiring extended temperature range, high reliability, or any other extraordinary environmental requirements unless pursuant to additional processing by Spectra Linear Inc., and an expressed written agreement by Spectra Linear Inc. Spectra Linear Inc. reserves the right to change any circuitry or specification without notice. Rev 1.4, May 25, 2007 Page 11 of 11