Product Data Sheet Integrated Circuit Systems, Inc. M908-01 VCSO BASED GBE CLOCK GENERATOR GENERAL DESCRIPTION PIN ASSIGNMENT (9 x 9 mm SMT) 27 26 25 24 23 22 21 20 19 XTAL_1 / REF_IN GND nFOUT5 FOUT5 nFOUT4 FOUT4 nFOUT3 FOUT3 VCC The M908-01 is a PLL (Phase Locked Loop) based clock generator that uses an internal VCSO (Voltage Controlled SAW Oscillator) to produce a very low jitter output clock. It is ideal for Gigabit Ethernet. The output clock (frequency of 156.25 or 187.50MHz for example) is provided from eight LVPECL clock output pairs. (Specify frequency at time of order.) The accuracy of the output frequency is assured by the internal PLL, which phase-locks the internal VCSO to the reference input frequency (25 or 30MHz for example). The input reference can either be an external crystal, utilizing the internal crystal oscillator, or a stable external clock source such as a packaged crystal oscillator. XTAL_2 FOUT6 nFOUT6 FOUT7 nFOUT7 VCC DNC DNC DNC 18 17 16 15 14 13 12 11 10 M908-01 (Top View) nFOUT2 FOUT2 nFOUT1 FOUT1 GND nFOUT0 FOUT0 VCC GND GND GND GND OP_IN nOP_OUT nVC VC OP_OUT nOP_IN 1 2 3 4 5 6 7 8 9 28 29 30 31 32 33 34 35 36 FEATURES Output clock frequency from 125MHz to 190MHz (Consult factory for frequency availability) Figure 1: Pin Assignment Eight identical LVPECL output pairs Integrated SAW (surface acoustic wave) delay line Example Output Frequency Configurations Low jitter 0.7ps RMS (over 12kHz-20MHz) Ref Clock Frequency (MHz) Ideal for Gigabit Ethernet clock reference Output-to-output skew < 100ps PLL Ratio 20 External XTAL or LVCMOS reference input 25 Industrial temperature grade available 25/4 30 Single 3.3V power supply Output Frequency 1 (MHz) Application 125.00 GbE 156.25 10GbE 187.50 12GbE Table 1: Example Output Frequency Configurations Note 1:Specify output clock frequency at time of order Small 9 x 9 mm SMT (surface mount) package SIMPLIFIED BLOCK DIAGRAM M908-01 FOUT7 nFOUT7 VSCO External Crystal or Reference Clock Input FOUT6 nFOUT6 FOUT5 nFOUT5 XTAL OSC Divider Frequency Multiplying PLL FOUT4 nFOUT4 FOUT3 nFOUT3 (e.g., 25 or 30 MHz) LVPECL Output Clock Pairs (e.g., 156.25 or 187.50MHz) FOUT2 nFOUT2 FOUT1 nFOUT1 FOUT0 nFOUT0 External Loop Filter Figure 2: Simplified Block Diagram M908-01 Datasheet Rev 2.1 Revised 30Jul2004 M908-01 VCSO Based GbE Clock Generator Integrated Circuit Systems, Inc. Communications Modules w w w. i c s t . c o m tel (508) 852-5400 M908-01 Integrated Circuit Systems, Inc. VCSO BASED GBE CLOCK GENERATOR Product Data Sheet DETAILED BLOCK DIAGRAM RLOOP CLOOP RPOST External Loop Filter Components CPOST CPOST RLOOP M908-01 XTAL_1 / REF_IN XTAL_2 OP_IN Phase Detector XTAL OSC nOP_IN CLOOP RPOST OP_OUT nOP_OUT nVC VC FOUT7 nFOUT7 SAW Delay Line RIN R Divider R=4 RIN Loop Filter Amplifier FOUT6 nFOUT6 Phase Shifter FOUT5 nFOUT5 VCSO M Divider M = 25 FOUT4 nFOUT4 Phase Locked Loop (PLL) FOUT3 nFOUT3 FOUT2 nFOUT2 FOUT1 nFOUT1 FOUT0 nFOUT0 Figure 3: Detailed Block Diagram PIN DESCRIPTIONS Number 1, 2, 3, 10, 14, 26 4 9 5 8 6 7 11, 19, 33 Name GND OP_IN nOP_IN nOP_OUT OP_OUT nVC VC VCC I/O 12 13 15 16 17 18 20 21 22 23 24 25 29 30 31 32 FOUT0 nFOUT0 FOUT1 nFOUT1 FOUT2 nFOUT2 FOUT3 nFOUT3 FOUT4 nFOUT4 FOUT5 nFOUT5 FOUT6 nFOUT6 FOUT7 nFOUT7 27 XTAL_1 / REF_IN Input 28 XTAL_2 Input 34, 35, 36 DNC Configuration Ground Description Power supply ground connections. Input External loop filter connections. See Figure 5, External Loop Filter, on pg. 4. Output Input Power Output Power supply connection, connect to +3.3V. No internal terminator Clock output pairs, differential LVPECL output (156.25 MHz for the M908-01-156.2500) External crystal connection. Also accepts LVCMOS/LVTTL compatible clock source. External crystal connection. Leave unconnected when driving pin 27 with external clock reference. Do Not Connect. Table 2: Pin Descriptions M908-01 Datasheet Rev 2.1 Integrated Circuit Systems, Inc. Revised 30Jul2004 2 of 6 Communications Modules w w w. i c s t . c o m tel (508) 852-5400 M908-01 Integrated Circuit Systems, Inc. VCSO BASED GBE CLOCK GENERATOR Product Data Sheet FUNCTIONAL DESCRIPTION Therefore, for the M908-01-156.2500: The M908-01 is a PLL (Phase Locked Loop) based clock generator that generates output clocks synchronized to an input reference clock. 25 156.25MHz = 25MHz x ---------4 M The product of the input crystal frequency and ----R falls within the lock range of the VCSO. The M908-01 combines the flexibility of a VCSO (Voltage Controlled SAW Oscillator) with the stability of a crystal oscillator. Input Reference The input reference can either be an external, discrete crystal device or a stable external clock source such as a packaged crystal oscillator: * If an external crystal is used with the on-chip crystal oscillator circuit (XTAL OSC), the external crystal should be a parallel-resonant, fundamental mode crystal. Apply it to the XTAL_1 / REF_IN and XTAL_2 input pins. External crystal load capacitors are also required. * If an external LVCMOS/LVTTL clock source is used, apply it to the XTAL_1 / REF_IN input pin. In either case, the reference clock is supplied to the phase detector of the PLL. The M908-01 includes a reference divider that divides the input reference frequency by a fixed value "R" and provides the result to the phase detector. APPLICATION INFORMATION This section includes information on the optional external crystal and on the external loop filter. The subsections on the loop filter provide example component values and also briefly describe the SAW PLL simulator tool and additional application information available at www.icst.com. External Crystal Specifications If an external crystal is used with the on-chip crystal oscillator circuit (XTAL OSC), the external crystal should have the following general specifications: Crystal Specifications Parameter f0 ESR The PLL CL The PLL (Phase Locked Loop) includes the phase detector, the VCSO, a feedback divider (labeled "M Divider"), and a reference divider ("R Divider"). P0 40 Equivalent Series Resistance Spurious Response (non-harmonic) Load Capacitance, 16 parallel load resonant 0.1 Drive Level 50 -40 dBc 32 pF 1.0 mW XTAL_1 / REF_IN C1 XTAL OSC XTAL XTAL_2 VCSO output frequency = 156.25MHz Input reference frequency = 25MHz M=25 R= 4 C2 Figure 4: Recommended External Crystal Configuration XTAL= 25 or 30 MHz, Load Capacitance Specification = 18 pF C1 = 27 pF C2 = 33 pF External load capacitors C1 and C2 present a load of 15 pf to the crystal (they are seen in series by the crystal through the common ground connection). With the additional of PCB trace capacitance and M908-01 input capacitance, the total load to the crystal is about 18 pf. Revised 30Jul2004 3 of 6 MHz Recommended External Crystal Configuration M908-01 M9xx-0x The relationship between the VCSO output frequency, the M Divider, the R Divider and the input reference frequency is defined as follows: M Fvcso = Fxtal x ----R For the M908-01-156.2500 (see "Ordering Information" on pg. 6): Integrated Circuit Systems, Inc. 16 The external crystal will be applied to the XTAL_1 / REF_IN and XTAL_2 input pins. External crystal load capacitors are also required. By controlling the frequency and phase of the VCSO, the phase detector precisely locks the frequency and phase of the feedback divider output to that of the reference divider output. This creates an output frequency that is a multiple of the reference frequency (which is output from the VCSO). M908-01 Datasheet Rev 2.1 AT-cut quartz Fundamental Table 3: Crystal Specifications The feedback divider divides the VCSO output frequency by a fixed value "M" to match the reference frequency provided to the phase detector by the reference divider. * * * * Min Typ Max Unit Crystal Type Mode of Oscillation Frequency Range Communications Modules w w w. i c s t . c o m tel (508) 852-5400 M908-01 Integrated Circuit Systems, Inc. VCSO BASED GBE CLOCK GENERATOR Product Data Sheet External Loop Filter To provide stable PLL operation, and thereby a low jitter output clock, the M908-01 requires the use of an external loop filter. This is provided via the provided filter pins (see Figure 5). External Loop Filter Component Values PLL Band- Damping R loop (k) width (kHz) Factor 0.5 Due to the differential signal path design, the implementation requires two identical complementary RC filters as shown here. RLOOP CLOOP 1.5 4.70 20 1500 3.3 4.7 1.00 10 1500 2.1 2 1.1 4.7 0.10 10 1500 6.4 4.5 20.0 0.10 20 270 10.6 3 4.2 33.0 0.033 20 120 Table 4: External Loop Filter Component Values CPOST OP_IN nOP_IN 4 RPOST CLOOP OP_OUT 9 nOP_OUT 8 nVC 5 6 Figure 5: External Loop Filter C post (pF) 3.0 CPOST RLOOP R post (k) 1 1.5 RPOST C loop (F) Note 1: Optimum loop bandwidth when using an external reference crystal. Will help to attenuate interference on the crystal's sinusoidal clock waveform and therefore will minimize device output clock jitter. Note 2: Alternative loop filter setting when using an external reference crystal. Smaller C loop lowers loop damping factor with negligible increase in output jitter. VC Note 3: Optimum loop bandwidth when using an external reference 7 crystal oscillator. The square wave clock reference does not require as much jitter attenuation, which allows for a wider loop bandwidth and improved system noise tolerance. Refer to the M908-01 product web page at www.icst.com/products/summary/m908-01.htm for additional product information. ABSOLUTE MAXIMUM RATINGS1 Symbol Parameter Rating Unit VI Input Voltage -0.5 to VCC +0.5 V VO Output Voltage -0.5 to VCC +0.5 V IO Output Current 21 mA VCC Power Supply Voltage 4.6 TS Storage Temperature V o -45 to +100 C Table 5: Absolute Maximum Ratings Note 1: 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 Recommended Conditions of Operation, DC Characteristics, or AC Characteristics is not implied. Exposure to absolute maximum rating conditions for extended periods may affect product reliability. RECOMMENDED CONDITIONS OF OPERATION Symbol Parameter VCC Positive Supply Voltage TA Ambient Operating Temperature Commercial Industrial Min Typ Max Unit 3.135 3.3 3.465 V 0 -40 oC +70 +85 oC Table 6: Recommended Conditions of Operation M908-01 Datasheet Rev 2.1 Integrated Circuit Systems, Inc. Revised 30Jul2004 4 of 6 Communications Modules w w w. i c s t . c o m tel (508) 852-5400 M908-01 Integrated Circuit Systems, Inc. VCSO BASED GBE CLOCK GENERATOR Product Data Sheet ELECTRICAL SPECIFICATIONS DC Characteristics Unless stated otherwise, VCC = 3.3V +5%,TA = 0 oC to +70 oC (commercial)1, TA = -40 oC to +85 oC (industrial)1, Output Frequency=156.25MHz1, LVPECL outputs terminated with 50 to VCC - 2V Symbol Parameter Power Supply Reference Clock Input Crystal or Reference Clock Input Differential Output VCC Positive Supply Voltage ICC Power Supply Current VIH Input High Voltage VIL Input Low Voltage IIH Input High Current IIL Input Low Current CIN Input Capacitance VOH Output High Voltage VOL Output Low Voltage VP-P Peak to Peak Output Voltage Min Typ Max Unit 3.135 3.3 3.465 V mA 375 (Vcc / 2 ) +0.5 Vcc +0.3 -0.3 XTAL_1 / REF_IN (XTAL_2 disconnected) (Vcc / 2 ) -0.5 V A 150 A -5.0 XTAL_1 / REF_IN FOUT, nFOUT (0-7) V 4 pF Vcc -1.4 Vcc -1.0 V Vcc -2.0 Vcc -1.7 V 0.85 V 0.5 Table 7: DC Characteristics Note 1: See Ordering Information on pg. 6 AC Characteristics Unless stated otherwise, VCC = 3.3V +5%,TA = 0 oC to +70 oC (commercial)1, TA = -40 oC to +85 oC (industrial)1, Output Frequency=156.25MHz1, LVPECL outputs terminated with 50 to VCC - 2V Symbol Parameter FOUT Output Frequency Range FIN Nominal Input Frequency, XTAL_1 / REF_IN APR VCSO Pull-Range n Single Side Band Phase Noise @156.25MHz Min Typ Max Unit 125 156.25 190 MHz +100 1kHz Offset 25 MHz +150 ppm -90 -110 -135 Test Conditions 0.7 1.0 dBc/Hz dBc/Hz dBc/Hz ps 45 50 55 % FOUT, nFOUT (0-7) 350 450 550 ps 20% to 80% Output Fall Time FOUT, nFOUT (0-7) 350 450 550 ps 20% to 80% Output Skew Between Any Pair 100 ps 10kHz Offset 100kHz Offset J(t) Jitter (rms) tDC Output Duty Cycle, High Time tR Output Rise Time tF tS Table 8: AC Characteristics Note 1: See Ordering Information on pg. 6 M908-01 Datasheet Rev 2.1 Integrated Circuit Systems, Inc. 12kHz to 20MHz Revised 30Jul2004 5 of 6 Communications Modules w w w. i c s t . c o m tel (508) 852-5400 Integrated Circuit Systems, Inc. M908-01 Product Data Sheet VCSO BASED GBE CLOCK GENERATOR DEVICE PACKAGE - 9 x 9mm CERAMIC LEADLESS CHIP CARRIER Mechanical Dimensions: Refer to the SAW PLL application notes web page at www.icst.com/products/appnotes/SawPllAppNotes.htm for application notes, including recommended PCB footprint, solder mask, and furnace profile. Figure 6: Device Package - 9 x 9mm Ceramic Leadless Chip Carrier ORDERING INFORMATION Part Numbering Scheme Part Number: Example Part Numbers M908- 01 - xxx.xxxx Device Number Output Freq. (MHz) Temperature " - " = 0 to +70 oC (commercial) I = - 40 to +85 oC (industrial) 125.00 156.25 Output Frequency (MHz) See Table 8, right. Consult ICS for other frequencies. Figure 7: Part Numbering Scheme 187.50 Temperature Order Part Number commercial industrial commercial industrial commercial industrial M908-01 - 125.0000 M908-01I125.0000 M908-01 - 156.2500 M908-01I156.2500 M908-01 - 187.5000 M908-01I187.5000 Table 9: Example Part Numbers Consult factory for frequency availability. 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. M908-01 Datasheet Rev 2.1 Integrated Circuit Systems, Inc. 6 of 6 Communications Modules Revised 30Jul2004 w w w. i c s t . c o m tel (508) 852-5400