NB4N441 3.3V Serial Input MultiProtocol PLL Clock Synthesizer, Differential LVPECL Output http://onsemi.com Description The NB4N441 is a precision clock synthesizer which generates a differential LVPECL clock output frequency from 12.5 MHz to 425 MHz. A Serial Peripheral Interface (SPI) is used to configure the device to produce one of sixteen popular standard protocol output frequencies from a single 27 MHz crystal reference. The NB4N441 also has the added feature of allowing application specific output frequencies from 12.5 MHz to 425 MHz using crystals within the range of 10 MHz to 28 MHz. MARKING DIAGRAM* 24 QFN−24 MN SUFFIX CASE 485L Features 27 MHz Crystal Reference Serial Load Capability for Proprietary Frequencies Flexible Input Allows for External Clock Reference Exceeds Bellcore and ITU Jitter Generation Specification PLL Lock Detect Output Output Enable Fully Integrated Phase−Lock−Loop with Internal Loop Filter Operating Range: VCC = 3.135 V to 3.465 V Small Footprint 24 Pin QFN These are Pb−Free Devices* NB4N 441 ALYWG G A = Assembly Location L = Wafer Lot Y = Year W = Work Week G = Pb−Free Package (Note: Microdot may be in either location) • Performs Precision Clock Generation and Synthesis from a Single • • • • • • • • • 1 *For additional marking information, refer to Application Note AND8002/D. ORDERING INFORMATION See detailed ordering and shipping information in the package dimensions section on page 11 of this data sheet. LOCKED 27 MHz XTAL OSC B R OUTDIV B2, 4, 8, 16, 32 FB Feedback Divider CLKOUT CLKOUT OE VCC − 2 V SDATA SCLOCK SLOAD Frequency Control Logic Serial Load Figure 1. Simplified Block Diagram *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. © Semiconductor Components Industries, LLC, 2011 April, 2011 − Rev. 2 1 Publication Order Number: NB4N441/D NB4N441 VCC CLK/XTAL1 XTAL2 LOCKED Input Prescaler XTAL OSC PB VCC_PLL PFD R Loop Filter VCO OUTDIV (NB) B2, 4, 8, 16, 32 FB Feedback Divider (MB) SDATA SCLOCK SLOAD P[4:0] M[9:0] N[3:0] Frequency Control Logic Serial Load GND VCC CLKOUT CLKOUT OE LOCKED GND Figure 2. Block Diagram 24 23 22 21 20 19 Exposed Pad (EP) 17 SCLOCK VCC_PLL 3 16 SDATA NC 4 15 SLOAD NC 5 14 NC GND 6 13 VCC 7 8 9 10 11 12 VCC 2 VCC NC NC GND GND 18 CLK/XTAL1 1 XTAL2 GND Figure 3. QFN−24 Lead Pinout (Top View) http://onsemi.com 2 OE CLKOUT CLKOUT NB4N441 Table 1. PIN DESCRIPTION Pin Name I/O 11, 12, 13, 24 VCC Power Supply Description 3 VCC_PLL PLL Power Supply 1, 6, 9, 18, 19 GND Ground 20 LOCKED LVTTL Lock Output 2, 4, 5, 10, 14 NC 8 CLK / XTAL1, 7 XTAL2 15 SLOAD** LVTTL / LVCMOS, Serial Load Input Serial Load. 16 SDATA** LVTTL / LVCMOS Serial Data Input Serial Data Input. 17 SCLOCK** LVTTL / LVCMOS Serial Clock Input Serial Clock Input. 21 OE* LVTTL Input 22, 23 CLKOUT CLKOUT LVPECL Output Positive supply voltage. Positive supply voltage for the PLL. Ground. When Low, this output provides indication that the PLL is locked and the device is in proper operating mode. When High, the PLL is out of lock. No Connect. LVTTL/LVCMOS Single Ended Clock or XTAL Inputs The crystal is connected between the XTAL1 and XTAL2 pin. If driving single−ended, use XTAL1 and leave XTAL2 floating. Synchronous Output Enable. When OE is HIGH or left OPEN, the outputs are enabled. When OE is LOW, the outputs are disabled. Differential LVPECL Clock Outputs, Typically terminated with 50 W resistor to VCC – 2.0 V. EP The Exposed Pad on the 24 pin QFN package bottom is thermally connected to the die for improved heat transfer out of package. The pad is not electrically connected to the die, but is recommended to be electrically connected to GND on the PC board. *Pins will default HIGH when left Open **Pins will default LOW when left Open http://onsemi.com 3 NB4N441 Table 2. STANDARD PROTOCOL / OUTPUT FREQUENCY SELECT TABLE WITH 27 MHz CRYSTAL REFERENCE # Protocol CLKOUT (MHz) Input Prescaler Divider P[4:0] PLL FB Divider M[9:0] Output Frequency Divider OUTDIV N[2:0] 0 OC−3 /STM−1 155.52 11001 1001000000 010 0 OC−12 / STM−4 155.52 11001 1001000000 010 0 OC−48 / STM−16 155.52 11001 1001000000 010 1 ETR 32 11011 1000000000 100 2 OC−1 51.84 11001 1100000000 100 3 Fast Ethernet 50 11011 1100100000 100 3 ESCON 50 11011 1100100000 100 4 FDDI 125 11011 0111110100 010 4 Infiniband 125 11011 0111110100 010 4 Gigabit Ethernet 125 11011 0111110100 010 4 PCIe 125 11011 0111110100 010 5 1/8 Fibre Channel 13.28125 11011 0110101001 101 6 1/4 Fibre Channel 26.5625 11011 1101010010 101 7 1/2 Fibre Channel 53.125 11011 1101010010 100 8 Fibre Channel 106.25 11011 1101010010 011 9 General 150 11011 1001011000 010 10 D1 Video 69 11011 1000101000 011 11 SONET Reference 19.44 11001 1001000000 101 12 2x Fibre Channel 212.5 11011 1101010010 010 13 4x Fibre Channel 425 11011 1101010010 001 14 XAUI 156.25 11011 1001110001 010 15 Serial ATA 100 11011 1100100000 011 16 HDTV 74.25 11011 1001010010 011 17 HDTV 148.50 11011 1001010010 010 Table 3. N−DIVIDER TABLE N2 N1 N0 N Divider 0 0 0 na 0 0 1 B2 0 1 0 B4 0 1 1 B8 1 0 0 B16 1 0 1 B32 1 1 0 na 1 1 1 na http://onsemi.com 4 NB4N441 Table 4. ATTRIBUTES Characteristics Value Internal Input Pullup Resistor 37.5kW Internal Input Pulldown Resistor 75kW ESD Protection Human Body Model Machine Model Moisture Sensitivity (Note 1) Flammability Rating > 1000 V > 150 V Level 1 Oxygen Index: 28 to 34 Transistor Count UL 94 V−0 @ 0.125 in 2102 Meets or exceeds JEDEC Spec EIA/JESD78 IC Latchup Test 1. For additional information, see Application Note AND8003/D. Table 5. MAXIMUM RATINGS (Note 2) Symbol Parameter Condition 1 Rating Unit 3.6 V 3.6 V Continuous Surge 50 100 mA mA QFN−24 −40 to +85 °C −65 to +150 °C VCC Positive Power Supply GND = 0 V VI Input Voltage GND = 0 V Iout LVPECL Output Current TA Operating Temperature Range Tstg Storage Temperature Range qJA Thermal Resistance (Junction−to−Ambient) (Note 3) qJC Thermal Resistance (Junction−to−Case) Tsol Wave Solder Condition 2 GND = VI = VCC 0 lfpm 500 lfpm QFN−24 QFN−24 °C/W °C/W 2S2P (Note 3) QFN−24 °C/W < 3 sec @ 260°C 265 °C Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. 2. Maximum Ratings are those values beyond which device damage may occur. 3. JEDEC standard multilayer board − 2S2P (2 signal, 2 power). http://onsemi.com 5 NB4N441 Table 6. DC CHARACTERISTICS VCC = 3.135 V to 3.465 V, GND = 0 V, TA = −40°C to +85°C Symbol Min Typ Max Unit ICC Power Supply Current (Inputs and Outputs Loaded) Characteristic 50 70 90 mA ICCPLL PLL Power Supply Current 10 20 30 mA VOH LVPECL Output HIGH Voltage (Notes 4 and 5) VCC = 3.3 V VCC – 1145 2155 VCC − 1030 2270 VCC – 895 2405 mV VOL LVPECL Output LOW Voltage (Notes 4 and 5) VCC = 3.3 V VCC – 1945 1355 VCC − 1760 1540 VCC – 1695 1605 mV VOHTTL Output HIGH Voltage (LOCKED Pin) VOLTTL Output LOW Voltage (LOCKED Pin) VIH IOH = −0.8 mA 2.5 VCC V GND 0.4 V Input HIGH Voltage (LVTTL/LVCMOS) 2.0 VCC V VIL Input LOW Voltage (LVTTL/LVCMOS) GND 0.8 V IIH Input HIGH Current, OE SCLK, SDATA, SLOAD OE, SCLK, SDATA, SLOAD VIN = 2.7 V, VCCmax VIN = 2.7 V, VCCmax VIN = VCC, VCCmax 6.0 20 20 26 60 60 mA mA IIL Input LOW Current VIN = 0.5 V, VCCmax 10 mA NOTE: Device will meet the specifications after thermal equilibrium has been established when mounted in a test socket or printed circuit board with maintained transverse airflow greater than 500 lfpm. Electrical parameters are guaranteed only over the declared operating temperature range. Functional operation of the device exceeding these conditions is not implied. Device specification limit values are applied individually under normal operating conditions and not valid simultaneously. 4. LVPECL Outputs loaded with 50 W termination resistors to VTT = VCC – 2.0 V for proper operation. 5. LVPECL Output parameters vary 1:1 with VCC. Table 7. AC CHARACTERISTICS VCC = 3.135 V to 3.465 V, GND = 0 V, TA = −40°C to +85°C (Note 6) Symbol Characteristic Min Typ Max Unit 28 50 10 MHz fIN Crystal Input Frequency External CLOCK Input Frequency (Pin 8) SCLOCK 10 27 27 VOUTPP Output Voltage Amplitude 600 800 fVCO VCO Frequency Range 400 850 MHz fCLKOUT Output Clock Frequency Range 12.5 425 MHz tR/tF_IN Input Clock Rise and Fall Time (CLK, Pin 8) (Note 7) 10 ns tLOCK Maximum PLL Lock Time 0.5 5 ms DCO Output CLOCK Duty Cycle (Differential Configuration) 52 % tJITTER(pd) Period Jitter (RMS, 1s, 10,000 Cycles) (Notes 8 and 9) 3.5 6.5 ps tJITTER(pd) Period Jitter (Peak−to−Peak, 10,000 Cycles) (Note 9) 25 40 ps ts Setup Time SDATA to SCLOCK SCLOCK to SLOAD 20 20 ns ns th Hold Time SDATA to SCLOCK SCLOCK to SLOAD 20 20 ns ns tpwmin Minimum Pulse Width SLOAD 20 tr, tf Output Rise/Fall Times (Note 7) CLKOUT / CLKOUT 175 48 mV ns 300 425 ps NOTE: Device will meet the specifications after thermal equilibrium has been established when mounted in a test socket or printed circuit board with maintained transverse airflow greater than 500 lfpm. Electrical parameters are guaranteed only over the declared operating temperature range. Functional operation of the device exceeding these conditions is not implied. Device specification limit values are applied individually under normal operating conditions and not valid simultaneously. 6. LVPECL Outputs loaded with 50 W to VCC − 2.0 V. 7. Measured 20% to 80% 8. Additive RMS jitter with 50% duty cycle input clock signal at 27.000 MHz; fOUT = 155 MHz. 9. fOUT = 155 MHz. Protocol 13.28125 MHz will have typical period jitter (RMS) of 14 ps and a typical cycle−to−cycle jitter of 95 ps. http://onsemi.com 6 NB4N441 APPLICATIONS INFORMATION General Lock Detect Functionality The NB4N441 is a precision clock synthesizer which generates a differential LVPECL clock output frequency from 12.5 MHz to 425 MHz. A three−wire SPI interface is used to configure the device to produce the exact frequency of one of sixteen predefined popular standard protocol output frequencies from a single 27 MHz crystal reference; see Table 1. This serial interface gives the user complete control of each internal counter/divider. If a different or custom output frequency is required, the SPI interface can also enable the user to configure the device for frequencies not specified in Table 1. The NB4N441 features a PLL Lock Detect function which indicates the locked status of the PLL. When the PLL is locked, the LOCKED output pin asserts a logic Low. When the internal phase lock is lost (such as when the input clock stops, drifts beyond the pullable range of the crystal, or suddenly shifts in phase), the LOCKED output goes High. Table 9. Table 9. Lock Detect Function LOCKED Function 0 PLL is Locked 1 PLL is not Locked Input Clock / Crystal Functionality To generate the exact protocol frequencies in Table 1, a 27.000 MHz frequency source is required. This can be accomplished by connecting a 27.000 MHz crystal across the XTAL1 and XTAL2 pins. If driving single ended, use the XTAL1 pin and leave XTAL2 floating. The CLK/XTAL1 input will accept a LVTTL/LVCMOS input. Using the On−Board Crystal Oscillator The NB4N441 features a fully integrated on−board crystal oscillator to minimize system implementation costs. The crystal should be fundamental mode, parallel resonant. For exact tuning of cyrstal frequency, capacitors should be connected from pins X1 and X2. Typical loading should be on the order of 20 pF to 30 pF (on each crystal input pin). As the oscillator is somewhat sensitive to loading on its inputs, the user is advised to mount the crystal as close to the NB4N441 as possible to avoid any board level parasitic effects. To facilitate collocation, surface mount crystals are recommended, but not required. Frequency Control Logic Configuration The NB4N441 includes a 5−bit input prescaler, a 10−bit divider for the PLL feedback path and a 3−bit Output Divider, which divides the VCO frequency by 2, 4, 8, 16, or 32. The Frequency Control Logic for the NB4N441 configures these dividers and counters through the Serial inputs and will select one of the sixteen predetermined clock frequencies in Table 1. The serial interface can also be used to configure the device for user specified custom frequencies not specified in Table 1. Output frequencies are generated based on the following equation: FOUT = (Fxtal/P) * M B N, with the stipulation that the internal VCO frequency be 400 MHz < VCO < 850 MHz with VCO = FOUT * N and 10 MHz < Fxtal < 28 MHz. Table 10. CRYSTAL SPECIFICATIONS Parameter Crystal Cut Fundamental AT Cut Resonance Parallel Resonance Load Capacitance Frequency Tolerance Frequency/Temperature Stability Operating Range Output Enable The NB4N441 incorporates a synchronous output Disable/Enable pin, OE. The synchronous output enable pin insures no runt clock pulses are generated. When disabled, CLKOUT is set LOW and CLKOUT is set HIGH. OE Function 1 Clock Outputs Enabled 0 Clock Outputs Disabled CLKOUT = L, CLKOUT = H ±15 ppm at 25°C ±20 ppm 0 to 70°C 0 to 70°C or −40 to +85°C 5 pF Max Equivalent Series Resistance (ESR) 50 W Max Aging http://onsemi.com 7 18 pF Shunt Capacitance Correlation Drive Level Table 8. Table 8. Output Enable Function Value 1.0 mW Max 5 ppm / Yr (First 3 Years) 15 ppm /10 Yrs NB4N441 3.3 V or 5.0 V the power supplies, a second level of isolation may be required. The simplest form of isolation is a power supply filter on the PLL_VCC Pin for the NB4N441. Figure 4 illustrates a typical power supply filter scheme. The NB4N441 is most susceptible to noise with spectral content in the 1 kHz to 1 MHz range. Therefore, the filter should be designed to target this range. The key parameter that needs to be met in the final filter design is the DC voltage drop that will be seen between the VCC supply and the PLL_VCC pin of the NB4N441. From the data sheet, the PLL_VCC current (the current sourced through the PLL_VCC Pin) is typically 26 mA. Assuming that a minimum of 2.9 V must be maintained on the PLL_VCC pin, very little DC voltage drop can be tolerated when a 3.3 V VCC supply is used. The resistor shown in Figure 4 must have a resistance of 5 W Max to meet the voltage drop criteria. The RC filter pictured will provide a broadband filter with approximately 100:1 attenuation for noise whose spectral content is above 20 kHz. As the noise frequency crosses the series resonant point of an individual capacitor, it’s overall impedance begins to look inductive and thus increases with increasing frequency. The parallel capacitor combination shown ensures that a low impedance path to ground exists for frequencies well above the bandwidth of the PLL. The level of required filtering is subject to further optimization and simplification. All the VCC pins are connected to the same VCC plane. All the ground pins (GND) are connected to the same GND plane. 3.3 V or 5.0 V RS = 5 W L=1000 mH R=15 W PLL_VCC 47 mF 0.01 mF VCC 0.01 mF Figure 4. Power Supply Filter Power Supply Filtering The NB4N441 is a mixed analog/digital product and as such, it exhibits some sensitivities that would not necessarily be seen on a fully digital product. Analog circuitry is naturally susceptible to random noise, especially if this noise is seen on the power supply pins. The NB4N441 provides separate power supplies for the digital circuitry (VCC) and the internal PLL (PLL_VCC) of the device. The purpose of this design technique is to try and isolate the high switching noise of the digital outputs from the relatively sensitive internal analog phase−locked loop. In a controlled environment such as an evaluation board, this level of isolation is sufficient. However, in a digital system environment where it is more difficult to minimize noise on http://onsemi.com 8 NB4N441 S_CLOCK P4 P3 S_DATA P2 P1 P0 N2 N1 N0 M9 M8 M7 First Bit S_LOAD M1 M0 Last Bit Figure 5. Serial Interface Timing Diagram S_DATA S_CLOCK tHOLD tSETUP Figure 6. Setup and Hold S_DATA S_LOAD M2 tHOLD tSETUP Figure 7. Setup and Hold http://onsemi.com 9 18 Bits NB4N441 Jitter Performance or cycle−to−cycle. If the scope is set up to trigger on every rising or falling edge, set to infinite persistence mode and allowed to trace sufficient cycles, it is possible to determine the maximum and minimum periods of the timing signal. Digital scopes can accumulate a large number of cycles, create a histogram of the edge placements and record peak−to−peak as well as standard deviations of the jitter. Care must be taken that the measured edge is the edge immediately following the trigger edge. These scopes can also store a finite number of period durations and post−processing software can analyze the data to find the maximum and minimum periods. Recent hardware and software developments have resulted in advanced jitter measurement techniques. The Tektronix TDS−series oscilloscopes have superb jitter analysis capabilities on non−contiguous clocks with their histogram and statistics capabilities. The Tektronix TDSJIT2/3 Jitter Analysis software provides many key timing parameter measurements and will extend that capability by making jitter measurements on contiguous clock and data cycles from single−shot acquisitions. M1 by Amherst was used as well and both test methods correlated. Long−Term Period Jitter is the maximum jitter observed at the end of a period’s edge when compared to the position of the perfect reference clock’s edge and is specified by the number of cycles over which the jitter is measured. The number of cycles used to look for the maximum jitter varies by application but the JEDEC spec is 10,000 observed cycles. The NBC4N441 exhibit long term and cycle−to−cycle jitter, which rivals that of SAW based oscillators. This jitter performance comes with the added flexibility associated with a synthesizer over a fixed frequency oscillator. The jitter data presented should provide users with enough information to determine the effect on their overall timing budget. The jitter performance meets the needs of most system designs while adding the flexibility of frequency margining and field upgrades. These features are not available with a fixed frequency SAW oscillator. Jitter is a common parameter associated with clock generation and distribution. Clock jitter can be defined as the deviation in a clock’s output transition from its ideal position. Cycle−to−Cycle Jitter (short−term) is the period variation between two adjacent cycles over a defined number of observed cycles. The number of cycles observed is application dependent but the JEDEC specification is 1000 cycles. T0 T1 TJITTER(cycle−cycle) = T1 − T0 Figure 8. Cycle−to−Cycle Jitter RMS or one Sigma Jitter Time Typical Gaussian Distribution Peak−to−Peak Jitter (8 s) Jitter Amplitude Peak−to−Peak Jitter is the difference between the highest and lowest acquired value and is represented as the width of the Gaussian base. Figure 9. Peak−to−Peak Jitter There are different ways to measure jitter and often they are confused with one another. The typical method of measuring jitter is to look at the timing signal with an oscilloscope and observe the variations in period−to−period http://onsemi.com 10 NB4N441 Zo = 50 W Q D Receiver Device Driver Device Q D Zo = 50 W 50 W 50 W VTT VTT = VCC − 2.0 V Figure 10. Typical Termination for Output Driver and Device Evaluation (See Application Note AND8020/D − Termination of ECL Logic Devices.) ORDERING INFORMATION Package Shipping† NB4N441MNG QFN−24 (Pb−Free) 92 Units / Rail NB4N441MNR2G QFN−24 (Pb−Free) 3000 / Tape & Reel Device †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. http://onsemi.com 11 NB4N441 PACKAGE DIMENSIONS QFN 24 MN SUFFIX 24 PIN QFN, 4x4 CASE 485L−01 ISSUE O D A PIN 1 IDENTIFICATION NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994. 2. CONTROLLING DIMENSION: MILLIMETERS. 3. DIMENSION b APPLIES TO PLATED TERMINAL AND IS MEASURED BETWEEN 0.25 AND 0.30 MM FROM TERMINAL. 4. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. B E DIM A A1 A2 A3 b D D2 E E2 e L 2X 0.15 C 2X 0.15 C A2 0.10 C A 0.08 C A3 A1 SEATING PLANE REF D2 C e L 7 MILLIMETERS MIN MAX 0.80 1.00 0.00 0.05 0.60 0.80 0.20 REF 0.23 0.28 4.00 BSC 2.70 2.90 4.00 BSC 2.70 2.90 0.50 BSC 0.35 0.45 12 6 13 E2 24X b 1 0.10 C A B 18 24 19 e 0.05 C ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. 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