Si53304 1:6 L OW J I T T E R U NIVERSAL B U F F E R /L EVEL T RANSLATOR WITH 2 : 1 I NPUT M UX A N D I NDIVIDUAL OE Features 6 differential or 12 LVCMOS outputs Ultra-low additive jitter: 45 fs rms Wide frequency range: 1 to 725 MHz Any-format input with pin selectable output formats: LVPECL, Low Power LVPECL, LVDS, CML, HCSL, LVCMOS 2:1 mux with hot-swappable inputs Glitchless input clock switching Synchronous output enable Individual output enable Independent VDD and VDDO: 1.8/2.5/3.3 V 1.2/1.5 V LVCMOS output support Excellent power supply noise rejection (PSRR) Selectable LVCMOS drive strength to tailor jitter and EMI performance Small size: 32-QFN (5x5 mm) RoHS compliant, Pb-free Industrial temperature range: –40 to +85 °C Ordering Information: See page 28. Applications High-speed clock distribution Ethernet switch/router Optical Transport Network (OTN) SONET/SDH PCI Express Gen 1/2/3 Storage Telecom Industrial Servers Backplane clock distribution Pin Assignments Si53304 Q1 Q2 Q2 Q3 Q3 Q4 Q4 32 31 30 29 28 27 26 25 OE 5 OE0 1 24 SFOUTA[1] 2 23 SFOUTB[1] SFOUTA[0] 3 22 SFOUTB[0] Q0 4 21 Q5 Q0 5 20 Q5 GND 6 19 V DDOB V DD 7 18 V DDOA CLK_SEL 8 17 V REF 9 10 11 12 13 14 15 16 OE1 CLK0 OE2 OE3 CLK1 CLK1 OE4 GND PAD CLK0 The Si53304 is an ultra low jitter six output differential buffer with pin-selectable output clock signal format and individual OE. The Si53304 features a 2:1 mux with glitchless switching, making it ideal for redundant clocking applications. The Si53304 utilizes Silicon Laboratories' advanced CMOS technology to fanout clocks from 1 to 725 MHz with guaranteed low additive jitter, low skew, and low propagation delay variability. The Si53304 features minimal cross-talk and provides superior supply noise rejection, simplifying low jitter clock distribution in noisy environments. Independent core and output bank supply pins provide integrated level translation without the need for external circuitry. Q1 Description Functional Block Diagram VDD VREF Vref Generator VDDOA SFOUTA[1:0] OE[2:0] Power Supply Filtering Patents pending CLK0 BANK A /CLK0 VDDOB SFOUTB[1:0] OE[5:3] CLK1 /CLK1 CLK_SEL Rev. 1.0 4/14 Switching Logic BANK B Copyright © 2014 by Silicon Laboratories Si53304 Si53304 TABLE O F C ONTENTS Section Page 1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 2. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.1. Universal, Any-Format Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.2. Input Bias Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.3. Input Clock Voltage Reference (VREF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.4. Universal, Any-Format Output Buffer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.5. Glitchless Clock Input Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.6. Synchronous Output Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.7. Input Mux and Output Enable Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.8. Power Supply (VDD and VDDOX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.9. Output Clock Termination Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 2.10. AC Timing Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.11. Typical Phase Noise Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.12. Input Mux Noise Isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2.13. Power Supply Noise Rejection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 4. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.1. 5x5 mm 32-QFN Package Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5. PCB Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 5.1. 5x5 mm 32-QFN Package Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 6. Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 6.1. Si53304 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 6.2. Top Marking Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32 Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 2 Rev. 1.0 Si53304 1. Electrical Specifications Table 1. Recommended Operating Conditions Parameter Ambient Operating Temperature Supply Voltage Range* Output Buffer Supply Voltage* Symbol Test Condition Min Typ Max Unit –40 — 85 °C 1.71 1.8 1.89 V 2.38 2.5 2.63 V 2.97 3.3 3.63 V LVPECL, low power LVPECL, LVCMOS 2.38 2.5 2.63 V 2.97 3.3 3.63 V HCSL 2.97 3.3 3.63 V LVDS, CML, LVCMOS 1.71 1.8 1.89 V 2.38 2.5 2.63 V 2.97 3.3 3.63 V 2.38 2.5 2.63 V 2.97 3.3 3.63 V 2.97 3.3 3.63 V TA VDD VDDOX LVDS, CML LVPECL, low power LVPECL HCSL *Note: Core supply VDD and output buffer supplies VDDO are independent. LVCMOS clock input is not supported for VDD = 1.8V but is supported for LVCMOS clock output for VDDOX = 1.8V. LVCMOS outputs at 1.5V and 1.2V can be supported via a simple resistor divider network. See “2.9.1. LVCMOS Output Termination To Support 1.5V and 1.2V” Table 2. Input Clock Specifications (VDD=1.8 V 5%, 2.5 V 5%, or 3.3 V 10%, TA=–40 to 85 °C) Parameter Symbol Test Condition Min Typ Max Unit Differential Input Common Mode Voltage VCM VDD = 2.5 V 5%, 3.3 V 10% 0.05 — — V Differential Input Swing (peak-to-peak) VIN 0.2 — 2.2 V LVCMOS Input High Voltage VIH VDD = 2.5 V 5%, 3.3 V 10% VDD x 0.7 — — V LVCMOS Input Low Voltage VIL VDD = 2.5 V 5%, 3.3 V 10% — — VDD x 0.3 V Input Capacitance CIN CLK0 and CLK1 pins with respect to GND — 5 — pF Rev. 1.0 3 Si53304 Table 3. DC Common Characteristics (VDD = 1.8 V 5%, 2.5 V 5%, or 3.3 V 10%,TA = –40 to 85 °C) Parameter Supply Current Output Buffer Supply Current (Per Clock Output) @100 MHz (diff) @200 MHz (CMOS) Symbol Test Condition Min Typ Max Unit — 65 100 mA LVPECL (3.3 V) — 35 — mA Low Power LVPECL (3.3 V)* — 35 — mA LVDS (3.3 V) — 20 — mA CML (3.3 V) — 35 — mA HCSL, 100 MHz, 2 pF load (3.3 V) — 35 — mA CMOS (1.8 V, SFOUT = Open/0), per output, CL = 5 pF, 200 MHz — 5 — mA CMOS (2.5 V, SFOUT = Open/0), per output, CL = 5 pF, 200 MHz — 8 — mA CMOS (3.3 V, SFOUT = 0/1), per output, CL = 5 pF, 200 MHz — 15 — mA IDD IDDOX Input Clock Voltage Reference VREF VREF pin IREF = +/-500 A — VDD/2 — V Input High Voltage VIH SFOUTx, CLK_SEL, OEx 0.8 x VDD — — V Input Mid Voltage VIM SFOUTx, 3-level input pins 0.45 x VDD 0.5 x VDD 0.55 x VDD V Input Low Voltage VIL SFOUTx, CLK_SEL, OEx — — 0.2 x VDD V Internal Pull-down Resistor RDOWN CLK_SEL, SFOUTx — 25 — k RUP OEx, SFOUTx — 25 — k Internal Pull-up Resistor *Note: Low-power LVPECL mode supports an output termination scheme that will reduce overall system power. 4 Rev. 1.0 Si53304 Table 4. Output Characteristics (LVPECL) (VDDOX = 2.5 V ± 5%, or 3.3 V ± 10%,TA = –40 to 85 °C) Parameter Symbol Output DC Common Mode Voltage Min Typ Max Unit VCOM VDDOX – 1.595 — VDDOX – 1.245 V VSE 0.55 0.80 1.050 V Single-Ended Output Swing* Test Condition *Note: Unused outputs can be left floating. Do not short unused outputs to ground. Table 5. Output Characteristics (Low Power LVPECL) (VDDOX = 2.5 V ± 5%, or 3.3 V ± 10%,TA = –40 to 85 °C) Parameter Symbol Test Condition Min Output DC Common Mode Voltage VCOM RL = 100 across Qn and Qn VDDOX – 1.895 VSE RL = 100 across Qn and Qn 0.25 Single-Ended Output Swing Typ 0.60 Max Unit VDDOX – 1.275 V 0.85 V Table 6. Output Characteristics—CML (VDDOX = 1.8 V 5%, 2.5 V 5%, or 3.3 V 10%,TA = –40 to 85 °C) Parameter Symbol Test Condition Min Typ Max Unit Single-Ended Output Swing VSE Terminated as shown in Figure 9 (CML termination). 300 400 550 mV Table 7. Output Characteristics—LVDS (VDDOX = 1.8 V 5%, 2.5 V 5%, or 3.3 V 10%,TA = –40 to 85 °C) Parameter Symbol Test Condition Min Typ Max Unit Single-Ended Output Swing VSE RL = 100 Ω across QN and QN 247 — 490 mV Output Common Mode Voltage (VDDO = 2.5 V or 3.3V) VCOM1 VDDOX = 2.38 to 2.63 V, 2.97 to 3.63 V, RL = 100 Ω across QN and QN 1.10 1.25 1.35 V Output Common Mode Voltage (VDDO = 1.8 V) VCOM2 VDDOX = 1.71 to 1.89 V, RL = 100 Ω across QN and QN 0.85 0.97 1.25 V Rev. 1.0 5 Si53304 Table 8. Output Characteristics—LVCMOS (VDDOX = 1.8 V 5%, 2.5 V 5%, or 3.3 V 10%,TA = –40 to 85 °C) Parameter Symbol Output Voltage High* Output Voltage Low* Test Condition Min Typ Max Unit VOH 0.75 x VDDOX — — V VOL — — 0.25 x VDDOX V *Note: IOH and IOL per the Output Signal Format Table for specific VDDOX and SFOUTx settings. Table 9. Output Characteristics—HCSL (VDDOX = 3.3 V ± 10%, TA = –40 to 85 °C)) Parameter Symbol Test Condition Min Typ Max Unit Output Voltage High VOH RL = 50 Ω to GND 550 700 900 mV Output Voltage Low VOL RL = 50 Ω to GND –150 0 150 mV Single-Ended Output Swing VSE RL = 50 Ω to GND 550 700 850 mV Crossing Voltage VC RL = 50 Ω to GND 250 350 550 mV Table 10. AC Characteristics (VDD = VDDOX = 1.8 V 5%, 2.5 V 5%, or 3.3 V 10%,TA = –40 to 85 °C) Parameter Frequency Duty Cycle Symbol Test Condition Min Typ Max Unit F LVPECL, low power LVPECL, LVDS, CML, HCSL 1 — 725 MHz LVCMOS 1 — 200 MHz 200 MHz, 20/80%TR/TF<10% of period (LVCMOS) (12 mA drive) 40 50 60 % 20/80% TR/TF<10% of period (Differential) 48 50 52 % Required to meet prop delay and additive jitter specifications (20–80%) 0.75 — — V/ns DC Note: 50% input duty cycle. Minimum Input Clock Slew Rate SR Notes: 1. HCSL measurements were made with receiver termination. See Figure 9 on page 18. 2. Output to Output skew specified for outputs with an identical configuration. 3. Defined as skew between any output on different devices operating at the same supply voltage, temperature, and equal load condition. Using the same type of inputs on each device, the outputs are measured at the differential cross points. 4. Measured for 156.25 MHz carrier frequency. Sine-wave noise added to VDDOX (3.3 V = 100 mVPP) and noise spur amplitude measured. See “AN491: Power Supply Rejection for Low-Jitter Clocks” for further details. 6 Rev. 1.0 Si53304 Table 10. AC Characteristics (Continued) (VDD = VDDOX = 1.8 V 5%, 2.5 V 5%, or 3.3 V 10%,TA = –40 to 85 °C) Parameter Output Rise/Fall Time Symbol Test Condition Min Typ Max Unit TR/TF LVDS, 20/80% — — 325 ps LVPECL, 20/80% — — 350 ps HCSL , 20/80% — — 280 ps CML, 20/80% — — 350 ps Low-Power LVPECL, 20/80% — — 325 ps LVCMOS 200 MHz, 20/80%, 2 pF load — — 750 ps 500 — — ps LVCMOS (12mA drive with no load) 1250 2000 2750 ps LVPECL 600 800 1000 ps LVDS 600 800 1000 ps F = 1 MHz — 2500 — ns F = 100 MHz — 30 — ns F = 725 MHz — 5 — ns F = 1 MHz — 2000 — ns F = 100 MHz — 30 — ns F = 725 MHz — 5 — ns LVCMOS (12 mA drive to no load) — 50 120 ps LVPECL — 35 70 ps LVDS — 35 70 ps TPS Differential — — 150 ps PSRR 10 kHz sinusoidal noise — –65 — dBc 100 kHz sinusoidal noise — –63 — dBc 500 kHz sinusoidal noise — –60 — dBc 1 MHz sinusoidal noise — –55 — dBc 1 Minimum Input Pulse Width Propagation Delay Output Enable Time Output Disable Time Output to Output Skew2 Part to Part Skew3 Power Supply Noise Rejection4 TW TPLH, TPHL TEN TDIS TSK Notes: 1. HCSL measurements were made with receiver termination. See Figure 9 on page 18. 2. Output to Output skew specified for outputs with an identical configuration. 3. Defined as skew between any output on different devices operating at the same supply voltage, temperature, and equal load condition. Using the same type of inputs on each device, the outputs are measured at the differential cross points. 4. Measured for 156.25 MHz carrier frequency. Sine-wave noise added to VDDOX (3.3 V = 100 mVPP) and noise spur amplitude measured. See “AN491: Power Supply Rejection for Low-Jitter Clocks” for further details. Rev. 1.0 7 Si53304 Table 11. Additive Jitter, Differential Clock Input VDD Output Input1,2 Freq (MHz) Clock Format Amplitude VIN (Single-Ended, Peak-to-Peak) Differential Clock Format 20%-80% Slew Rate (V/ns) Additive Jitter (fs rms, 12 kHz to 20 MHz)3 Typ Max 3.3 725 Differential 0.15 0.637 LVPECL 45 65 3.3 725 Differential 0.15 0.637 LVDS 50 65 3.3 156.25 Differential 0.5 0.458 LVPECL 160 185 3.3 156.25 Differential 0.5 0.458 LVDS 150 200 2.5 725 Differential 0.15 0.637 LVPECL 45 65 2.5 725 Differential 0.15 0.637 LVDS 50 65 2.5 156.25 Differential 0.5 0.458 LVPECL 145 185 2.5 156.25 Differential 0.5 0.458 LVDS 145 195 Notes: 1. For best additive jitter results, use the fastest slew rate possible. See “AN766: Understanding and Optimizing Clock Buffer’s Additive Jitter Performance” for more information. 2. AC-coupled differential inputs. 3. Measured differentially using a balun at the phase noise analyzer input. See Figure 1. 8 Rev. 1.0 Si53304 Table 12. Additive Jitter, Single-Ended Clock Input VDD Output Input1,2 Freq (MHz) Clock Format Amplitude VIN (single-ended, peak to peak) Additive Jitter (fs rms, 12 kHz to 20 MHz)3 SE 20%-80% Slew Rate (V/ns) Clock Format Typ Max 3.3 200 Single-ended 1.70 1 LVCMOS4 120 160 3.3 156.25 Single-ended 2.18 1 LVPECL 160 185 3.3 156.25 Single-ended 2.18 1 LVDS 150 200 3.3 156.25 Single-ended 2.18 1 LVCMOS4 130 180 2.5 200 Single-ended 1.70 1 LVCMOS5 120 160 2.5 156.25 Single-ended 2.18 1 LVPECL 145 185 2.5 156.25 Single-ended 2.18 1 LVDS 145 195 2.5 156.25 Single-ended 2.18 1 LVCMOS5 140 180 Notes: 1. For best additive jitter results, use the fastest slew rate possible. See “AN766: Understanding and Optimizing Clock Buffer’s Additive Jitter Performance” for more information. 2. DC-coupled single-ended inputs. 3. Measured differentially using a balun at the phase noise analyzer input. See Figure 1. 4. Drive Strength: 12 mA, 3.3 V (SFOUT = 11). LVCMOS jitter is measured single-ended. 5. Drive Strength: 9 mA, 2.5 V (SFOUT = 11). LVCMOS jitter is measured single-ended. PSPL 5310A CLK SYNTH SMA103A 50 Si533xx DUT Balun PSPL 5310A CLKx AG E5052 Phase Noise Analyzer 50ohm /CLKx 50 Balun Figure 1. Differential Measurement Method Using a Balun Rev. 1.0 9 Si53304 Table 13. Thermal Conditions Parameter Symbol Test Condition Value Unit Thermal Resistance, Junction to Ambient JA Still air 49.6 °C/W Thermal Resistance, Junction to Case JC Still air 32.3 °C/W Table 14. Absolute Maximum Ratings Parameter Symbol Storage Temperature Min Typ Max Unit TS –55 — 150 C Supply Voltage VDD –0.5 — 3.8 V Input Voltage VIN –0.5 — VDD+ 0.3 V Output Voltage VOUT — — VDD+ 0.3 V ESD Sensitivity HBM — — 2000 V ESD Sensitivity CDM — — 500 V Peak Soldering Reflow Temperature TPEAK — — 260 C — — 125 C Maximum Junction Temperature Test Condition HBM, 100 pF, 1.5 k Pb-Free; Solder reflow profile per JEDEC J-STD-020 TJ Note: Stresses beyond those listed in this table may cause permanent damage to the device. Functional operation specification compliance is not implied at these conditions. Exposure to maximum rating conditions for extended periods may affect device reliability. 10 Rev. 1.0 Si53304 2. Functional Description The Si53304 is a low jitter, low skew 1:6 differential buffer with an integrated 2:1 input mux and individual OE control. The device has a universal input that accepts most common differential or LVCMOS input signals. A clock select pin control is used to select the active input clock. The selected clock input is routed to two independent banks of outputs. Each output bank features control pins to select signal format setting and LVCMOS drive strength. In addition, each clock output has an independent OE pin for individual clock enable/disable. 2.1. Universal, Any-Format Input The universal input stage enables simple interfacing to a wide variety of clock formats, including LVPECL, lowpower LVPECL, LVCMOS, LVDS, HCSL, and CML. Tables 15 and 16 summarize the various ac- and dc-coupling options supported by the device. For the best high-speed performance, the use of differential formats is recommended. For both single-ended and differential input clocks, the fastest possible slew rate is recommended as low slew rates can increase the noise floor and degrade jitter performance. Though not required, a minimum slew rate of 0.75 V/ns is recommended for differential formats and 1.0 V/ns for single-ended formats. See “AN766: Understanding and Optimizing Clock Buffer’s Additive Jitter Performance” for more information. Table 15. LVPECL, LVCMOS, and LVDS Input Clock Options LVPECL LVCMOS LVDS AC-Couple DC-Couple AC-Couple DC-Couple AC-Couple DC-Couple 1.8 V N/A N/A No No Yes No 2.5/3.3 V Yes Yes No Yes Yes Yes Table 16. HCSL and CML Input Clock Options HCSL CML AC-Couple DC-Couple AC-Couple DC-Couple 1.8 V No No Yes No 2.5/3.3 V Yes (3.3 V) Yes (3.3 V) Yes No 0.1 µF Si533xx CLKx 100 /CLKx 0.1 µF Figure 2. Differential HCSL, LVPECL, Low-Power LVPECL, LVDS, CML AC-Coupled Input Termination VDD 1 k VDDO= 3.3 V or 2.5 V VDD Si533xx CMOS Driver CLKx 50 /CLKx Rs VTERM = VDD/2 1 k VREF Figure 3. LVCMOS DC-Coupled Input Termination Rev. 1.0 11 Si53304 VDDO DC Coupled LVPECL Termination Scheme 1 R1 VDD R1 VDDO = 3.3V or 2.5V Si533xx CLKx 50 “Standard” LVPECL Driver /CLKx 50 R2 VTERM = VDDO – 2V R1 // R2 = 50 Ohm R2 3.3V LVPECL: R1 = 127 Ohm, R2 = 82.5 Ohm 2.5V LVPECL: R1 = 250 Ohm, R2 = 62.5 Ohm DC Coupled LVPECL Termination Scheme 2 VDD VDDO = 3.3V or 2.5V Si533xx 50 “Standard” LVPECL Driver CLKx /CLKx 50 50 50 VTERM = VDDO – 2V DC Coupled LVDS Termination VDD VDDO = 3.3V or 2.5V Si533xx CLKx 50 Standard LVDS Driver /CLKx 50 100 DC Coupled HCSL Source Termination Scheme VDDO = 3.3V 33 Si533xx 50 Standard HCSL Driver VDD CLKx /CLKx 33 50 50 50 Note: 33 Ohm series termination is optional depending on the location of the receiver. Figure 4. Differential DC-Coupled Input Terminations 12 Rev. 1.0 Si53304 2.2. Input Bias Resistors Internal bias resistors ensure a differential output low condition in the event that the clock inputs are not connected. The non-inverting input is biased with a 18.75 k pull-down to GND and a 75 k pull-up to VDD. The inverting input is biased with a 75 k pull-up to VDD. VDD RPU RPU + RPD CLK0 or CLK1 – RPU = 75 k RPD = 18.75 k Figure 5. Input Bias Resistors 2.3. Input Clock Voltage Reference (VREF) The VREF pin is used to bias the input receiver when a differential input clock is terminated as a single-ended reference clock to the device. Connect the single-ended input to either CLK0 or CLK1. Use the recommended input termination and bias circuit as shown in Figure 3. Note that the VREF pin should be left floating when LVCMOS or differential clocks are used. Si533xx CLKx / CLKx VREF 100 nF Figure 6. Using Voltage Reference with Single-Ended Input Clock Rev. 1.0 13 Si53304 2.4. Universal, Any-Format Output Buffer The highly flexible output drivers support a wide range of clock signal formats, including LVPECL, low power LVPECL, LVDS, CML, HCSL, and LVCMOS. SFOUTx[1] and SFOUTx[0] are 3-level inputs that can be pinstrapped to select the Bank A and Bank B clock signal formats independently. This feature enables the device to be used for format translation in addition to clock distribution, minimizing the number of unique buffer part numbers required in a typical application and simplifying design reuse. For EMI reduction applications, four LVCMOS drive strength options are available for each VDDO setting. Table 17. Output Signal Format Selection SFOUTX[1] SFOUTX[0] VDDOX = 3.3 V VDDOX = 2.5 V VDDOX = 1.8 V Open* Open* LVPECL LVPECL N/A 0 0 LVDS LVDS LVDS 0 1 LVCMOS, 24 mA drive LVCMOS, 18 mA drive LVCMOS, 12 mA drive 1 0 LVCMOS, 18 mA drive LVCMOS, 12 mA drive LVCMOS, 9 mA drive 1 1 LVCMOS, 12 mA drive LVCMOS, 9 mA drive LVCMOS, 6 mA drive Open* 0 LVCMOS, 6 mA drive LVCMOS, 4 mA drive LVCMOS, 2 mA drive Open* 1 LVPECL low power LVPECL low power N/A 0 Open* CML CML CML 1 Open* HCSL N/A N/A *Note: SFOUTx are 3-level input pins. Tie low for “0” setting. Tie high for “1” setting. When left open, the pin floats to VDD/2. 14 Rev. 1.0 Si53304 2.5. Glitchless Clock Input Switching The input clock mux features glitchless switching between two valid input clocks. Figure 7 illustrates that switching between input clocks does not generate runt pulses or glitches at the output. CLK1 CLK0 CLK_SEL Note 1 Note 2 Note 3 Qn Notes: 1. Qn continues with CLK0 for 2-3 falling edges of CLK0. 2. Qn is disabled low for 2-3 falling edges of CLK1 . 3. Qn starts on the first rising edge after 1 + 2. Figure 7. Glitchless Input Clock Switch Glitchless switching between 2 input clocks that are up to 10x different in frequency is supported. When a switchover to a new clock is made, the output will disable low after two or three clock cycles of the previouslyselected input clock. The outputs will remain low for up to three clock cycles of the newly-selected clock, after which the outputs will start from the newly-selected input. In the case a switchover to an absent clock is made, the output will glitchlessly stop low and wait for edges of the newly selected clock. A switchover from an absent clock to a live clock will also be glitchless. Note that the CLK_SEL input should not be toggled faster than 1/250th the frequency of the slower input clock. 2.6. Synchronous Output Enable This buffer features a synchronous output enable (disable) feature. Output enable is sampled and synchronized on the falling edge of the input clock. This feature prevents runt pulses from being generated when the outputs are enabled or disabled. When OE is low, Q is held low and Q is held high for differential output formats. For LVCMOS output format options, both Q and Q are held low when OE is set low. The device outputs are enabled when the output enable pin is unconnected. See Table 10, “AC Characteristics,” on page 6 for output enable and output disable times. Rev. 1.0 15 Si53304 2.7. Input Mux and Output Enable Logic Two clock inputs for applications that need to select between one of two clock sources. The CLK_SEL pin selects the active clock input. The table below summarizes the input and output clock based on the input mux and output enable pin settings. Table 18. Input Mux and Output Enable Logic CLK_SEL CLK0 CLK1 OE1 Q2 L L X H L L H X H H H X L H L H X H H H X X X L L3 Notes: 1. Output enable active high 2. On the next negative transition of CLK0 or CLK1. 3. Single-end: Q = low, Q = low Differential: Q = low, Q = high 2.8. Power Supply (VDD and VDDOX) The device includes separate core (VDD) and output driver supplies (VDDOX). This feature allows the core to operate at a lower voltage than VDDO, reducing current consumption in mixed supply applications. The core VDD supports 3.3 V, 2.5 V, or 1.8 V. Each output bank has its own VDDOX supply, supporting 3.3 V, 2.5 V, or 1.8 V. 16 Rev. 1.0 Si53304 2.9. Output Clock Termination Options The recommended output clock termination options are shown below. VDDO DC Coupled LVPECL Termination Scheme 1 R1 R1 VDDO = 3.3V or 2.5V Si533xx VDD = VDDO 50 Q LVPECL Receiver Qn 50 R2 VTERM = VDDO – 2V R1 // R2 = 50 Ohm R2 3.3V LVPECL: R1 = 127 Ohm, R2 = 82.5 Ohm 2.5V LVPECL: R1 = 250 Ohm, R2 = 62.5 Ohm DC Coupled LVPECL Termination Scheme 2 VDDO = 3.3V or 2.5V Si533xx VDD = VDDO 50 Q LVPECL Receiver Qn 50 50 50 VTERM = VDDO – 2V VDDO AC Coupled LVPECL Termination Scheme 1 R1 VDDO = 3.3V or 2.5V Si533xx R1 0.1 uF VDD = 3.3V or 2.5V 50 Q LVPECL Receiver Qn 50 0.1 uF Rb R2 Rb R2 VBIAS = VDD – 1.3V R1 // R2 = 50 Ohm 3.3V LVPECL: R1 = 82.5 Ohm, R2 = 127 Ohm, Rb = 120 Ohm 2.5V LVPECL: R1 = 62.5 Ohm, R2 = 250 Ohm, Rb = 90 Ohm AC Coupled LVPECL Termination Scheme 2 V DDO = 3.3V or 2.5V Si533xx 0.1 uF V DD = 3.3V or 2.5V 50 Q LVPECL Receiver Qn 50 0.1 uF Rb Rb 50 50 V BIAS = V DD – 1.3 V 3.3V LVPECL: Rb = 120 Ohm 2.5V LVPECL: Rb = 90 Ohm Figure 8. LVPECL Output Termination Rev. 1.0 17 Si53304 DC Coupled LVDS and Low-Power LVPECL Termination VDDO = 3.3 V or 2.5 V, or 1.8 V (LVDS only) Si533xx VDD 50 Q Standard LVDS Receiver Qn 50 100 AC Coupled LVDS and Low-Power LVPECL Termination VDDO = 3.3 V or 2.5 V or 1.8 V (LVDS only) Si533xx 0.1 uF VDD 50 Q Standard LVDS Receiver Qn 50 0.1 uF 100 AC Coupled CML Termination VDDO = 3.3V or 2.5V or 1.8V Si533xx 0.1 uF VDD 50 Q Standard CML Receiver 100 Qn 50 0.1 uF DC Coupled HCSL Receiver Termination VDDO = 3.3V Si533xx VDD 50 Q Standard HCSL Receiver Qn 50 50 50 DC Coupled HCSL Source Termination VDDO = 3.3V Si533xx VDD 42.2 50 Q Qn 42.2 50 86.6 Standard HCSL Receiver 86.6 Figure 9. LVDS, CML, HCSL, and Low-Power LVPECL Output Termination 18 Rev. 1.0 Si53304 CMOS Receivers Si533xx CMOS Driver Zout Rs Zo 50 Figure 10. LVCMOS Output Termination Table 19. Recommended LVCMOS RS Series Termination SFOUTX[1] SFOUTX[0] RS (ohms) 3.3 V 2.5 V 1.8 V 0 1 33 33 33 1 0 33 33 33 1 1 33 33 0 Open 0 0 0 0 2.9.1. LVCMOS Output Termination To Support 1.5V and 1.2V LVCMOS clock outputs are natively supported at 1.8, 2.5, and 3.3V. However, 1.2V and 1.5V LVCMOS clock outputs can be supported via a simple resistor divider network that will translate the buffer’s 1.8V output to a lower voltage as shown in Figure 11 below. VDDOx= 1.8V R1 50 R2 LVCMOS 1.5V LVCMOS: R1 = 43 ohms, R2 = 300 ohms, IOUT = 12mA 1.2V LVCMOS: R1 = 58 ohms, R2 = 150 ohms, IOUT = 12mA R1 50 R2 Figure 11. 1.5V and 1.2V LVCMOS Low-Voltage Output Termination Rev. 1.0 19 Si53304 2.10. AC Timing Waveforms TPHL TSK VPP/2 CLK Q VPP/2 QN QM VPP/2 VPP/2 TPLH TSK Propagation Delay Output-Output Skew TF Q 80% VPP 20% VPP Rise/Fall Time Figure 12. AC Waveforms 20 80% VPP 20% VPP Q Rev. 1.0 TR Si53304 2.11. Typical Phase Noise Performance Each of the following three figures shows three phase noise plots superimposed on the same diagram. Source Jitter: Reference clock phase noise. Total Jitter (SE): Combined source and clock buffer phase noise measured as a single-ended output to the phase noise analyzer and integrated from 12 kHz to 20 MHz. Total Jitter (Diff): Combined source and clock buffer phase noise measured as a differential output to the phase noise analyzer and integrated from 12 kHz to 20 MHz. The differential measurement as shown in each figure is made using a balun. See Figure 1 on page 9. Note: To calculate the total RMS phase jitter when adding a buffer to your clock tree, use the root-sum-square (RSS). The total jitter is a measure of the source plus the buffer's additive phase jitter. The additive jitter (rms) of the buffer can then be calculated (via root-sum-square addition). Figure 13. Source Jitter (156.25 MHz) Rev. 1.0 21 Si53304 Figure 14. Single-Ended Total Jitter (312.5 MHz) 22 Rev. 1.0 Si53304 Figure 15. Differential Total Jitter (625 MHz) Rev. 1.0 23 Si53304 2.12. Input Mux Noise Isolation The buffer’s input clock mux is designed to minimize crosstalk between the CLK0 and CLK1. This improves phase jitter performance when clocks are present at both the CLK0 and CLK1 inputs. Figure 16 below is a measurement the input mux’s noise isolation. LVPECL [email protected]; Selected clk is active Unselected clk is static Mux Isolation = 61dB LVPECL [email protected]; Selected clk is static Unselected clk is active Figure 16. Input Mux Noise Isolation 2.13. Power Supply Noise Rejection The device supports on-chip supply voltage regulation to reject noise present on the power supply, simplifying low jitter operation in real-world environments. This feature enables robust operation alongside FPGAs, ASICs and SoCs and may reduce board-level filtering requirements. For more information, see “AN491: Power Supply Rejection for Low Jitter Clocks”. 24 Rev. 1.0 Q1 Q1 Q2 Q2 Q3 Q3 Q4 Q4 Si53304 32 31 30 29 28 27 26 25 OE0 1 24 OE5 SFOUTA[1] 2 23 SFOUTB[1] SFOUTA[0] 3 22 SFOUTB[0] Q0 4 21 Q5 Q0 5 20 Q5 GND 6 19 VDDOB VDD 7 18 VDDOA CLK_SEL 8 17 VREF 10 11 12 13 14 15 16 CLK0 CLK0 OE2 OE3 CLK1 CLK1 OE4 OE1 9 GND PAD Table 20. Pin Description Pin Name Type* Description 1 OE0 I Output enable—Output 0 When OE = high, the Q0 is enabled. When OE = low, Q is held low and Q is held high for differential formats. For LVCMOS, both Q and Q are held low when OE is set low. This pin contains an internal pull-up resistor. 2 SFOUTA[1] I Output signal format control pin for Bank A Three level input control. Internally biased at VDD/2. Can be left floating or tied to ground or VDD. 3 SFOUTA[0] I Output signal format control pin for Bank A Three level input control. Internally biased at VDD/2. Can be left floating or tied to ground or VDD. 4 Q0 O Output clock 0 (complement) 5 Q0 O Output clock 0 6 GND O Ground 7 VDD P Core voltage supply Bypass with 1.0 µF capacitor and place as close to the VDD pin as possible. Rev. 1.0 25 Si53304 Table 20. Pin Description (Continued) 26 Pin Name Type* Description 8 CLK_SEL I Mux input select pin (LVCMOS) Clock inputs are switched without the introduction of glitches. When CLK_SEL is high, CLK1 is selected. When CLK_SEL is low, CLK0 is selected. CLK_SEL contains an internal pull-down resistor. 9 OE1 I Output enable—Output 1 When OE = high, the Q1 is enabled. When OE = low, Q is held low and Q is held high for differential formats. For LVCMOS, both Q and Q are held low when OE is set low. This pin contains an internal pull-up resistor. 10 CLK0 I Input clock 0 11 CLK0 I Input clock 0 (complement) When the CLK0 is driven by a single-end input, connect CLK0 to VDD/2. 12 OE2 I Output enable—Output 2 When OE = high, the Q2 is enabled. When OE = low, Q is held low and Q is held high for differential formats. For LVCMOS, both Q and Q are held low when OE is set low. OE2 contains an internal pull-up resistor. 13 OE3 I Output enable—Output 3 When OE = high, the Q3 is enabled. When OE = low, Q is held low and Q is held high for differential formats. For LVCMOS, both Q and Q are held low when OE is set low. OE3 contains an internal pull-up resistor. 14 CLK1 I Input clock 1 15 CLK1 I Input clock 1 (complement) When the CLK1 is driven by a single-end input, connect CLK1 to VDD/2. 16 OE4 I Output enable—Output 4 When OE = high, the Q4 is enabled. When OE = low, Q is held low and Q is held high for differential formats. For LVCMOS, both Q and Q are held low when OE is set low. This pin contains an internal pull-up resistor. 17 VREF O Input clock reference voltage used to bias CLK0 or CLK1 clock input pins. VREF is required when a differential input clock is applied to the device and terminated as a single-ended reference. VREF may be left unconnected for LVCMOS or differential clock inputs. See “2.3. Input Clock Voltage Reference (VREF)” for details. 18 VDDOA P Output voltage supply—Bank A (Outputs: Q0 to Q2) Bypass with 1.0 µF capacitor and place as close to the VDDOA pin as possible. Rev. 1.0 Si53304 Table 20. Pin Description (Continued) Pin Name Type* Description 19 VDDOB P Output voltage supply—Bank B (Outputs: Q3 to Q5) Bypass with 1.0 µF capacitor and place as close to the VDDOB pin as possible. 20 Q5 O Output clock 5 (complement) 21 Q5 O Output clock 5 22 SFOUTB[0] I Output signal format control pin for Bank B Three level input control. Internally biased at VDD/2. Can be left floating or tied to ground or VDD. 23 SFOUTB[1] I Output signal format control pin for Bank B Three level input control. Internally biased at VDD/2. Can be left floating or tied to ground or VDD. 24 OE5 I Output enable—Output 5 When OE = high, the Q5 is enabled. When OE = low, Q is held low and Q is held high for differential formats. For LVCMOS, both Q and Q are held low when OE is set low. This pin contains an internal pull-up resistor. 25 Q4 O Output clock 4 (complement) 26 Q4 O Output clock 4 27 Q3 O Output clock 3 (complement) 28 Q3 O Output clock 3 29 Q2 O Output clock 2 (complement) 30 Q2 O Output clock 2 31 Q1 O Output clock 1 (complement) 32 Q1 O Output clock 1 GND Pad GND GND Ground Pad Power supply ground and thermal relief. *Pin types are: I = input, O = output, P = power, GND = ground. Rev. 1.0 27 Si53304 3. Ordering Guide Part Number Package PB-Free, ROHS-6 Temperature Si53304-B-GM 32-QFN Yes –40 to 85 C Si53301/4-EVB Evaluation Board Yes — Notes: 1. To buy, go to http://www.supplier-direct.com/silabs/Cart.aspx?supplierUVID=63410000&partnumber=Si53304-BGM&quantity=1&issample=0. 2. To sample, go to http://www.supplier-direct.com/silabs/Cart.aspx?supplierUVID=63410000&partnumber=Si53304-BGM&quantity=1&issample=1. 28 Rev. 1.0 Si53304 4. Package Outline 4.1. 5x5 mm 32-QFN Package Diagram Figure 17. Si53304 5x5 mm Package Diagram Table 21. Package Dimensions Dimension Min Nom Max A 0.80 0.85 1.00 A1 0.00 0.02 0.05 b 0.18 0.25 0.30 c 0.20 0.25 0.30 D D2 5.00 BSC 2.00 2.15 e 0.50 BSC E 5.00 BSC 2.30 E2 2.00 2.15 2.30 L 0.30 0.40 0.50 aaa 0.10 bbb 0.10 ccc 0.08 ddd 0.10 Notes: 1. All dimensions shown are in millimeters (mm) unless otherwise noted. 2. Dimensioning and Tolerancing per ANSI Y14.5M-1994. 3. This drawing conforms to the JEDEC Solid State Outline MO-220. Rev. 1.0 29 Si53304 5. PCB Land Pattern 5.1. 5x5 mm 32-QFN Package Land Pattern Figure 18. Si53304 5x5 mm Package Land Pattern Table 22. PCB Land Pattern Dimension Min Max Dimension Min Max C1 4.52 4.62 X2 2.20 2.30 C2 4.52 4.62 Y1 0.59 0.69 Y2 2.20 2.30 E X1 0.50 BSC 0.20 0.30 Notes: General 1. All dimensions shown are in millimeters (mm) unless otherwise noted. 2. This Land Pattern Design is based on the IPC-7351 guidelines. Solder Mask Design 1. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad is to be 60 m minimum, all the way around the pad. Stencil Design 1. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure good solder paste release. 2. The stencil thickness should be 0.125 mm (5 mils). 3. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads. 4. A 2x2 array of 0.75 mm square openings on 1.15 mm pitch should be used for the center ground pad. Card Assembly 1. A No-Clean, Type-3 solder paste is recommended. 2. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components. 30 Rev. 1.0 Si53304 6. Top Marking 6.1. Si53304 Top Marking 6.2. Top Marking Explanation Mark Method: Laser Font Size: 2.0 Point (28 mils) Center-Justified Line 1 Marking: Device Part Number 53304 Line 2 Marking: Device Revision/Type B-GM Line 3 Marking: YY = Year WW = Work Week Corresponds to the year and work week of the mold date. Line 4 Marking R = Die Rev F = Wafer Fab Manufacturing Code. Circle = 0.5 mm Diameter Lower-Left Justified Pin 1 Identifier A = Assembly Site I = Internal Code XX = Serial Lot Number Last four characters of the Manufacturing Code from the Assembly Purchase Order form. Rev. 1.0 31 Si53304 DOCUMENT CHANGE LIST Revision 0.4 to Revision 1.0 Corrected Improved front-page buffer block diagram. performance specifications with more detail. Added additional information to clarify the use of the voltage reference feature. Added pin type description to Table 20, “Pin Description,” on page 25. Added low-voltage termination options for 1.2 V and 1.5 V LVCMOS support. Clarified output clock bank A and bank B assignments. 32 Rev. 1.0 ClockBuilder Pro One-click access to Timing tools, documentation, software, source code libraries & more. Available for Windows and iOS (CBGo only). www.silabs.com/CBPro Timing Portfolio www.silabs.com/timing SW/HW Quality Support and Community www.silabs.com/CBPro www.silabs.com/quality community.silabs.com Disclaimer Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using or intending to use the Silicon Laboratories products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific device, and "Typical" parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only. Silicon Laboratories reserves the right to make changes without further notice and limitation to product information, specifications, and descriptions herein, and does not give warranties as to the accuracy or completeness of the included information. Silicon Laboratories shall have no liability for the consequences of use of the information supplied herein. This document does not imply or express copyright licenses granted hereunder to design or fabricate any integrated circuits. The products must not be used within any Life Support System without the specific written consent of Silicon Laboratories. A "Life Support System" is any product or system intended to support or sustain life and/or health, which, if it fails, can be reasonably expected to result in significant personal injury or death. Silicon Laboratories products are generally not intended for military applications. Silicon Laboratories products shall under no circumstances be used in weapons of mass destruction including (but not limited to) nuclear, biological or chemical weapons, or missiles capable of delivering such weapons. Trademark Information Silicon Laboratories Inc., Silicon Laboratories, Silicon Labs, SiLabs and the Silicon Labs logo, CMEMS®, EFM, EFM32, EFR, Energy Micro, Energy Micro logo and combinations thereof, "the world’s most energy friendly microcontrollers", Ember®, EZLink®, EZMac®, EZRadio®, EZRadioPRO®, DSPLL®, ISOmodem ®, Precision32®, ProSLIC®, SiPHY®, USBXpress® and others are trademarks or registered trademarks of Silicon Laboratories Inc. ARM, CORTEX, Cortex-M3 and THUMB are trademarks or registered trademarks of ARM Holdings. Keil is a registered trademark of ARM Limited. All other products or brand names mentioned herein are trademarks of their respective holders. Silicon Laboratories Inc. 400 West Cesar Chavez Austin, TX 78701 USA http://www.silabs.com