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Integrated Circuit Systems, Inc.
Product Data Sheet
M908-01
VCSO BASED GBE CLOCK GENERATOR
PIN ASSIGNMENT (9 x 9 mm SMT)
XTAL_1 / REF_IN GND nFOUT5 FOUT5 nFOUT4 FOUT4 nFOUT3 FOUT3 VCC XTAL_2 FOUT6 nFOUT6 FOUT7 nFOUT7 VCC DNC DNC DNC 27 26 25 24 23 22 21 20 19
GENERAL DESCRIPTION
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.
28 29 30 31 32 33 34 35 36
M908-01
(Top View)
18 17 16 15 14 13 12 11 10
nFOUT2 FOUT2 nFOUT1 FOUT1 GND nFOUT0 FOUT0 VCC GND
FEATURES
Output clock frequency from 125MHz to 190MHz (Consult factory for frequency availability) Eight identical LVPECL output pairs Integrated SAW (surface acoustic wave) delay line Low jitter 0.7ps RMS (over 12kHz-20MHz) Ideal for Gigabit Ethernet clock reference Output-to-output skew < 100ps External XTAL or LVCMOS reference input Industrial temperature grade available Single 3.3V power supply Small 9 x 9 mm SMT (surface mount) package
Figure 1: Pin Assignment
Example Output Frequency Configurations
Ref Clock Frequency (MHz) 20 25 30 25/4 PLL Ratio Output Frequency 1 (MHz) 125.00 156.25 187.50 Application
GND GND GND OP_IN nOP_OUT nVC VC OP_OUT nOP_IN
1 2 3 4 5 6 7 8 9
GbE 10GbE 12GbE
Table 1: Example Output Frequency Configurations
Note 1:Specify output clock frequency at time of order
SIMPLIFIED BLOCK DIAGRAM
M908-01
FOUT7 nFOUT7
VSCO
FOUT6 nFOUT6 FOUT5 nFOUT5
External Crystal or Reference Clock Input
(e.g., 25 or 30 MHz)
XTAL OSC
Divider
Frequency Multiplying PLL
FOUT4 nFOUT4 FOUT3 nFOUT3 FOUT2 nFOUT2 FOUT1 nFOUT1 FOUT0 nFOUT0
LVPECL Output Clock Pairs
(e.g., 156.25 or 187.50MHz)
External Loop Filter
Figure 2: Simplified Block Diagram
M908-01 Datasheet Rev 2.1
M908-01 VCSO Based GbE Clock Generator
Revised 30Jul2004
Integrated Circuit Systems, Inc.
Communications Modules
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Integrated Circuit Systems, Inc.
M908-01
VCSO BASED GBE CLOCK GENERATOR
Product Data Sheet
DETAILED BLOCK DIAGRAM
RLOOP CLOOP RPOST CPOST CPOST RLOOP CLOOP OP_OUT RPOST nOP_OUT nVC VC
External Loop Filter Components
M908-01
Phase Detector
OP_IN
nOP_IN
XTAL_1 / REF_IN XTAL_2
RIN
SAW Delay Line
XTAL OSC
R Divider
R=4 RIN Loop Filter Amplifier Phase Shifter VCSO
FOUT7 nFOUT7 FOUT6 nFOUT6 FOUT5 nFOUT5 FOUT4 nFOUT4 FOUT3 nFOUT3 FOUT2 nFOUT2 FOUT1 nFOUT1 FOUT0 nFOUT0
M Divider M = 25
Phase Locked Loop (PLL)
Figure 3: Detailed Block Diagram
PIN DESCRIPTIONS
Number 1, 2, 3, 10, 14, 26 4 9 5 8 6 7 11, 19, 33 12 13 15 16 17 18 20 21 22 23 24 25 29 30 31 32 27 28 34, 35, 36 Name GND OP_IN nOP_IN nOP_OUT OP_OUT nVC VC VCC FOUT0 nFOUT0 FOUT1 nFOUT1 FOUT2 nFOUT2 FOUT3 nFOUT3 FOUT4 nFOUT4 FOUT5 nFOUT5 FOUT6 nFOUT6 FOUT7 nFOUT7 XTAL_1 / REF_IN XTAL_2 DNC I/O Configuration Description
Ground Input Output Input Power
Power supply ground connections. External loop filter connections. See Figure 5, External Loop Filter, on pg. 4. Power supply connection, connect to +3.3V.
Output
No internal terminator
Clock output pairs, differential LVPECL output (156.25 MHz for the M908-01-156.2500)
Input Input
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.
2 of 6 Communications Modules
Revised 30Jul2004
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Integrated Circuit Systems, Inc.
M908-01
VCSO BASED GBE CLOCK GENERATOR
Product Data Sheet Therefore, for the M908-01-156.2500:
FUNCTIONAL DESCRIPTION
The M908-01 is a PLL (Phase Locked Loop) based clock generator that generates output clocks synchronized to an input reference clock. 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:
25 156.25MHz = 25MHz x --------4 M The product of the input crystal frequency and ---R falls within the lock range of the VCSO.
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 Min Typ Max Unit AT-cut quartz Fundamental 16 40 50
* 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. The PLL The PLL (Phase Locked Loop) includes the phase detector, the VCSO, a feedback divider (labeled "M Divider"), and a reference divider ("R Divider"). 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. 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). 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):
f0
ESR
Crystal Type Mode of Oscillation Frequency Range
MHz
CL P0
Equivalent Series Resistance Spurious Response (non-harmonic) Load Capacitance, 16 parallel load resonant 0.1 Drive Level
-40 dBc pF mW
32 1.0
Table 3: Crystal Specifications
The external crystal will be applied to the XTAL_1 / REF_IN and XTAL_2 input pins. External crystal load capacitors are also required.
Recommended External Crystal Configuration M908-01 M9xx-0x
XTAL_1 / REF_IN
C1
XTAL XTAL_2
C2
XTAL OSC
Figure 4: Recommended External Crystal Configuration
* * * *
VCSO output frequency = 156.25MHz Input reference frequency = 25MHz M=25 R= 4
3 of 6
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.
M908-01 Datasheet Rev 2.1
Integrated Circuit Systems, Inc.
Revised 30Jul2004
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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). Due to the differential signal path design, the implementation requires two identical complementary RC filters as shown here.
RLOOP CLOOP RPOST CPOST CPOST RLOOP OP_IN
4 9
M908-01
VCSO BASED GBE CLOCK GENERATOR
Product Data Sheet External Loop Filter Component Values
PLL Band- Damping R loop (k) width (kHz) Factor 0.5 1.5 6.4 10.6 3
1
C loop (F) 4.70 1.00 0.10 0.10 0.033
R post (k) 20 10 10 20 20
C post (pF) 1500 1500 1500 270 120
3.0 3.3 1.1 4.5 4.2
1.5 4.7 4.7 20.0 33.0
2.1 2
Table 4: External Loop Filter Component Values
CLOOP OP_OUT
8 5
RPOST nOP_OUT nVC
6
nOP_IN
Figure 5: External Loop Filter
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 VO IO VCC TS
Input Voltage Output Voltage Output Current Power Supply Voltage Storage Temperature
-0.5 to VCC +0.5 -0.5 to VCC +0.5
21 4.6
V V mA 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 Min 3.135 Typ 3.3 Max 3.465 Unit
VCC TA
Positive Supply Voltage Ambient Operating Temperature Commercial Industrial
V
oC oC
0 -40
+70 +85
Table 6: Recommended Conditions of Operation
M908-01 Datasheet Rev 2.1
Integrated Circuit Systems, Inc.
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Revised 30Jul2004
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Integrated Circuit Systems, Inc.
M908-01
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
Min 3.135
Typ 3.3 375
Max 3.465
Unit
Power Supply
VCC ICC
Positive Supply Voltage Power Supply Current Input High Voltage Input Low Voltage Input High Current Input Low Current Input Capacitance Output High Voltage Output Low Voltage Peak to Peak Output Voltage
FOUT, nFOUT (0-7)
V mA
Reference Clock Input
VIH VIL IIH IIL
(Vcc / 2 ) +0.5 XTAL_1 / REF_IN (XTAL_2 disconnected) -0.3 -5.0 XTAL_1 / REF_IN Vcc -1.4 Vcc -2.0
0.5
Vcc +0.3
150
V A A
(Vcc / 2 ) -0.5 V
Crystal or Reference Clock Input Differential Output
CIN VOH VOL VP-P
4
pF V V V
Vcc -1.0 Vcc -1.7
0.85
Note 1: See Ordering Information on pg. 6
Table 7: DC Characteristics
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
Min 125
Typ 156.25 25
Max 190
Unit
Test Conditions
FOUT FIN APR n
Output Frequency Range Nominal Input Frequency, XTAL_1 / REF_IN VCSO Pull-Range Single Side Band Phase Noise @156.25MHz Jitter (rms) Output Duty Cycle, High Time Output Rise Time Output Fall Time Output Skew
FOUT, nFOUT (0-7) FOUT, nFOUT (0-7) 1kHz Offset 10kHz Offset 100kHz Offset
MHz MHz ppm dBc/Hz dBc/Hz dBc/Hz ps % ps ps ps
Table 8: AC Characteristics
+100
+150 -90 -110 -135
0.7 1.0 55 550 550 100
J(t) tDC tR tF tS
12kHz to 20MHz
45 350 350
50 450 450
20% to 80% 20% to 80%
Between Any Pair
Note 1: See Ordering Information on pg. 6
M908-01 Datasheet Rev 2.1
Integrated Circuit Systems, Inc.
5 of 6 Communications Modules
Revised 30Jul2004
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Integrated Circuit Systems, Inc.
Product Data Sheet
M908-01
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:
Device Number Temperature " - " = 0 to +70 oC (commercial) I = - 40 to +85 oC (industrial) Output Frequency (MHz) See Table 8, right. Consult ICS for other frequencies.
Example Part Numbers
M908- 01 - xxx.xxxx
Output Freq. (MHz) 125.00 156.25 187.50
Temperature
Order Part Number M908-01 - 125.0000 M908-01I125.0000 M908-01 - 156.2500 M908-01I156.2500 M908-01 - 187.5000 M908-01I187.5000
Figure 7: Part Numbering Scheme
commercial industrial commercial industrial commercial industrial
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.
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