ICST M2051-11I625.0000 Saw pll for 10gbe 64b/66b fec Datasheet

M2050/51/52
Preliminary Information
Integrated
Circuit
Systems, Inc.
SAW PLL FOR 10GBE 64B/66B FEC
GENERAL DESCRIPTION
PIN ASSIGNMENT (9 x 9 mm SMT)
27
26
25
24
23
22
21
20
19
FIN_SEL1
GND
P_SEL2
DIF_REF0
nDIF_REF0
REF_SEL
DIF_REF1
nDIF_REF1
VCC
The M2050/51/52 is a VCSO (Voltage Controlled SAW
Oscillator) based clock PLL
designed for FEC clock ratio
translation in 10Gb optical systems
such as 10GbE 64b/66b. It supports
both mapping and de-mapping of
64b/66b encoding and FEC
(Forward Error Correction) clock
multiplication ratios. The ratios are pin-selected from
pre-programming look-up tables.
FIN_SEL0
FEC_SEL0
FEC_SEL1
LOL
NBW
VCC
DNC
DNC
DNC
FEATURES
M2050
M2051
M2052
(Top View)
P_SEL0
P_SEL1
nFOUT0
FOUT0
GND
nFOUT1
FOUT1
VCC
GND
18
17
16
15
14
13
12
11
10
1
2
3
4
5
6
7
8
9
◆ Integrated SAW delay line; Output of 15 to 700 MHz *
28
29
30
31
32
33
34
35
36
GND
GND
GND
OP_IN
nOP_OUT
nVC
VC
OP_OUT
nOP_IN
◆ Low phase jitter < 0.5 ps rms typical
(12kHz to 20MHz or 50Hz to 80MHz)
◆ Pin-selectable PLL divider ratios support 64b/66b and
FEC encoding/decoding ratios:
• M2050: Map 10GbE to LAN, 255/238 FEC, or 255/237 FEC
• M2051: De-map 10GbE LAN or 255/238 FEC to 10GbE
• M2052: De-map 255/237 FEC & 255/238 FEC to 10GbE LAN
Figure 1: Pin Assignment
Example I/O Clock Frequency Combinations
◆ Scalable dividers provide further adjustment of loop
bandwidth as well as jitter tolerance
Using M2050 Mapper PLL
◆ LVPECL clock output (CML and LVDS options available)
◆ Reference clock inputs support differential LVDS,
LVPECL, as well as single-ended LVCMOS, LVTTL
◆ Loss of Lock (LOL) output pin
◆ Narrow Bandwidth control input (NBW Pin)
Base Input
Rate (MHz)1
Mapper Ratio
Mfec / Rfec
(Pin Selectable)
VCSO* and Base
Output Rate
(MHz)2
625.0000
33 / 32
644.5313
625.0000
15 / 14
669.6429
15 / 14
690.5692
644.5313
◆ Hitless Switching (HS) options with or without Phase
Build-out (PBO) available; performance conforms with
SONET (GR-253) /SDH (G.813) MTIE and TDEV during
reference clock reselection
Table 1: Example I/O Clock Frequency Combinations
Note 1: Input reference clock can be base rate divided by “Mfin”.
Note 2: Output rate can be base rate divided by “P”.
* Specify VCSO center frequency at time of order.
◆ Single 3.3V power supply
◆ Small 9 x 9 mm SMT (surface mount) package
SIMPLIFIED BLOCK DIAGRAM
Loop
Filter
M2050, 51, 52
NBW
LOL
MUX
DIF_REF0
nDIF_REF0
0
DIF_REF1
nDIF_REF1
1
Phase
Detector
Rfec
Div
VCSO
Mfec Div
REF_SEL
FEC_SEL1:0
FIN_SEL1:0
P_SEL2:0
2
Mfin Divider
(1, 4, 5, 25)
Mfec and Rfec
Divider
LUT
P Divider
(1, 4, 5, 25 or TriState)
Mfin Divider
LUT
2
FOUT0
nFOUT0
TriState
FOUT1
nFOUT1
P Divider
LUT
3
Figure 2: Simplified Block Diagram
M2050/51/52 Datasheet Rev 1.0
Revised 23Jun2005
M2050/51/52 SAW PLL for 10GbE 64b/66b FEC
Integrated Circuit Systems, Inc.
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M2050/51/52
Integrated
Circuit
Systems, Inc.
SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
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
25
FOUT1
nFOUT1
FOUT0
nFOUT0
P_SEL1
P_SEL0
P_SEL2
20
nDIF_REF1
21
DIF_REF1
22
REF_SEL
23
nDIF_REF0
24
DIF_REF0
27
28
29
30
FIN_SEL1
FIN_SEL0
FEC_SEL0
FEC_SEL1
31
LOL
Output
32
NBW
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. 8.
Output
Input
Power supply connection, connect to +3.3V.
Power
Output
No internal terminator
Clock output pair 1. Differential LVPECL.
Output
No internal terminator
Clock output pair 0. Differential LVPECL.
, P divider selection. LVCMOS/LVTTL. See Table 7,
Internal pull-down resistor1 Post-PLL
P Divider Look-Up Table (LUT), on pg. 4.
Input
Biased to Vcc/2 2
Input
Reference clock input pair 1. Differential LVPECL or LVDS.
Internal pull-down resistor1 Resistor bias on inverting terminal supports TTL or LVCMOS.
Input
Internal pull-down resistor1
Biased to Vcc/2 2
Input
Internal pull-down resistor 1
Reference clock input selection. LVCMOS/LVTTL:
Logic 1 selects DIF_REF1, nDIF_REF1.
Logic 0 selects DIF_REF0, nDIF_REF0.
Reference clock input pair 0. Differential LVPECL or LVDS.
Resistor bias on inverting terminal supports TTL or LVCMOS.
nput clock frequency selection. LVCMOS/LVTTL. See
Internal pull-down resistor1 ITable
3 Mfin Divider Look-Up Tables (LUT) on pg. 3.
Mfec
and
Rfec divider value selection. LVCMOS/ LVTTL.
Internal pull-down resistor1 See Tables 4, 5,and 6 on pg. 3.
Input
Input
Internal pull-UP resistor1
Loss of Lock indicator output. Asserted when internal PLL is
not tracking the input reference for frequency and phase. 3
Logic 1 indicates loss of lock.
Logic 0 indicates locked condition.
Narrow Bandwidth enable. LVCMOS/LVTTL:
Logic 1 - Narrow loop bandwidth, RIN = 2100kΩ.
Logic 0 - Wide bandwidth, RIN = 100kΩ.
Do Not Connect.
Table 2: Pin Descriptions
Note 1: For typical values of internal pull-down and pull-up resistors, see DC Characteristics on pg. 10.
Note 2: Biased toVcc/2, with 50kΩ to Vcc and 50kΩ to ground. See Differential Inputs Biased to VCC/2 in DC Characteristics on pg. 10.
Note 3: See LVCMOS Output in DC Characteristics on pg. 10.
M2050/51/52 Datasheet Rev 1.0
Integrated Circuit Systems, Inc.
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M2050/51/52
Integrated
Circuit
Systems, Inc.
SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
DETAILED BLOCK DIAGRAM
R LOOP
C LOOP
R POST
External
Loop Filter
Components
C POST
C POST
R LOOP
OP_IN
M2050, 51, 52
nOP_IN
C LOOP
R POST
OP_OUT
nOP_OUT
nVC
VC
Hitless Switch Option
NBW
Phase Buildout Option
LOL
MUX
DIF_REF0
nDIF_REF0
0
DIF_REF1
nDIF_REF1
1
Phase
Detector
R IN
Phase
Locked
Loop
(PLL)
Rfec
Div
R IN
Loop Filter
Amplifier
SAW Delay Line
Phase
Shifter
VCSO
FEC_SEL1:0
Mfin Divider
(1, 4, 5, 25)
Mfec Div
REF_SEL
Mfec/Rfec Divider
LUT
Mfin Divider
LUT
FIN_SEL1:0
FOUT0
nFOUT0
P Divider
(1, 4, 5, 25,
or TriState)
FOUT1
nFOUT1
P Divider
LUT
P_SEL2:0
Figure 3: Detailed Block Diagram
DIVIDER SELECTION TABLES
Mfin Divider Look-Up Tables (LUT)
Mfec and Rfec Divider Look-Up Tables (LUTs)
The FIN_SEL1:0 pins select the feedback divider value
(“Mfin”). Since the VCSO frequency is fixed, this allows
input reference selection. The look-up tables vary by
device variant.
The FEC_SEL pins select the Mfec/Rfec divider ratio.
The look-up tables vary by device variant. The Mfec
and Rfec values also establish phase detector
frequency. A lower phase detector frequency improves
jitter tolerance and lowers loop bandwidth.
M2050: Map LUT (10GbE to LAN, 255/238 FEC, or 255/237 FEC)
M2050/51/52: Mfin Value LUT
FIN_SEL1:0
0
0
1
1
0
1
0
1
Mfin Sample Input Reference Freq. (MHz) Options
Value For M20501, M2051 & M20522
25
5
4
1
25.00
125.00
156.25
625.00
FEC_SEL1:0
Mfec Rfec
1 0
Fvcso =
Base Input Base
Output
Rate (MHz) Rate (MHz)
Description
For M2050 with Fvcso = 644.5313 (10GbE to 10GbE LAN rate):
0
0
Table 3: M2050/51/52: Mfin Value LUT
Note 1: For M2050 with Fvcso = 669.6429
Note 2: For M2051 and M2052 with Fvcso = 625.0000.
0
1
33 32
33 33
625.0000
644.5313
10GbE to 10GbE LAN
10GbE LAN repeater
644.5313
644.5313
For M2050 with Fvcso = 669.6429 (10GbE to 10GbE 255/238 FEC rate):
1
1
0
1
15 14
15 15
10GbE to 10GbE 255/238 FEC
10GbE 255/238 FEC repeater
625.0000
669.6429
669.6429
669.6429
For M2050 with Fvcso = 690.5692 (10GbE LAN to 10GbE LAN 255/238 FEC):
10GbE LAN to 10GbE LAN
1 0 15 14 255/238 FEC
644.5313 690.5692
1
1
15 15
10GbE LAN 255/238 FEC repeater
690.5692
690.5692
For M2050 with Fvcso = 693.4830 (10GbE LAN to 10GbE LAN 255/237 FEC):
10GbE LAN to 10GbE LAN
0 0 85 79 255/237 FEC
644.5313 693.4830
0
1
85 85
10GbE LAN 255/237 FEC repeater
693.4830
693.4830
Table 4: M2050: Map LUT (10GbE to LAN, 255/238 FEC, or 255/237 FEC)
M2050/51/52 Datasheet Rev 1.0
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M2050/51/52
Integrated
Circuit
Systems, Inc.
SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
M2051: De-map LUT (10GbE LAN or 255/238 FEC to 10GbE)
P Divider Look-Up Table (LUT)
Use this option to demap from either “10GbE LAN” or
“10GbE 255/238 FEC” encoded to “10GbE”. Also use
this option to operate in 10GbE repeater mode.
The P_SEL2:0 pins select the P divider values, which set
the output clock frequencies. A P divider of value of 1
will provide a 625.00MHz output when using a 625.00MHz
VCSO, for example. P divider values of 4, 5, or 25 are
also available, plus a TriState mode. The outputs can
be placed into the valid state combinations as listed in
Table 7. (The outputs cannot each be placed into any of
the five available states independently.)
The de-mapper FEC PLL ratios (in Table 5) enables
the M2051-11-625.0000 to accept “base” input
reference frequencies of: 625.00MHz (“10GbE”),
644.5313MHz (“10GbE LAN”), and
669.6429MHz (“10GbE 255/238 FEC”).
P Value
FEC_SEL1:0
Mfec Rfec
1 0
Description
Fvcso =
Base Input Base
Output
Rate (MHz) Rate (MHz)
For M2051 with Fvcso = 625.00
0
0
32
33
10GbE LAN to 10GbE
644.5313
625.0000
0
1
32
32
10GbE jitter attenuator
625.0000
625.0000
1
0
28
30
10GbE 255/238 FEC to 10GbE
669.6429
625.0000
1
1 14 15 10GbE 255/238 FEC to 10GbE 669.6429 625.0000
Table 5: M2051: De-map LUT (10GbE LAN or 255/238 FEC to 10GbE)
The Mfec divider value for the first three settings allows
one set of passive filter components to be used for all
three of these modes.
The fourth setting maps “10GbE 255/238 FEC” using
the lowest Mfec value possible. Use this setting to
produce the maximum loop bandwidth.
M2052: De-map LUT (255/237 or 255/238 FEC to 10GbE LAN)
This option de-maps from both “10GbE LAN 255/237
FEC” and “10GbE LAN 255/238 FEC” to “10GbE LAN”.
Also use this option to operate in 10GbE LAN repeater
mode.
Description
Fvcso =
Base Input Base
Output
Rate (MHz) Rate (MHz)
For M2052 with Fvcso = 625.00
0
0
79
85
0
1
79
79
1
1
0
84
90
1
84
84
10GbE LAN 255/237 FEC to
10GbE LAN
10GbE LAN jitter attenuator
693.4830
625.0000
644.5313
625.0000
10GbE LAN 255/238 FEC to
10GbE LAN
10GbE LAN jitter attenuator
690.5692
625.0000
644.5313
625.0000
Table 6: M2052: De-map LUT (255/237 or 255/238 FEC to 10GbE LAN)
Use this option for multi-rate de-mapping applications
that require one set of PLL passive filter values to
operate over both “10GbE LAN 255/237 FEC” and
“10GbE LAN 255/238 FEC”. The Mfec divider value is
kept nearly constant to maintain similar loop bandwidth
using one set of external filter component values.
M2050/51/52 Datasheet Rev 1.0
Integrated Circuit Systems, Inc.
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
M2050-625.0000
for FOUT0 for FOUT1
Output Frequency (MHz)
25
1
25
4
1
1
4
1
5
5
4
4
5
4
TriState TriState
FOUT1
25.00
25.00
625.00
156.25
125.00
156.25
125.00
N/A
625.00
156.25
625.00
625.00
125.00
156.25
156.25
N/A
Table 7: P Divider Look-Up Table (LUT)
General Guideline for Mfec and Rfec Divider Selection
When LOL is to be used for system health monitoring,
the phase detector frequency should be 5MHz or
greater. Low phase detector frequencies make LOL
overly sensitive, and higher phase detector frequencies
make LOL less sensitive. The LOL pin should not be used
during loop timing mode.
FUNCTIONAL DESCRIPTION
An internal high "Q" SAW delay line provides low jitter
signal performance and establishes the output
frequency of the VCSO (Voltage Controlled SAW
Oscillator). In a given M2050/51/52 device, the VCSO
center frequency is fixed. A common center frequency
is 625.00MHz, for 10GbE 64b/66b optical network
applications. The VCSO center frequency is specified at
time of order (see “Ordering Information” on pg. 12).
The VCSO has a guaranteed tuning range of ±120 ppm
(commercial temperature grade).
Pin selectable dividers are used within the PLL and
for the output clock. This enables tailoring of device
functionality and performance. The FEC feedback and
reference dividers (the “Mfec Divider” and “Rfec
Divider”) provide the multiplication ratios necessary to
accomodate clock translation for both forward and
inverse Forward Error Correction. The Mfec and Rfec
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FOUT0
The M2050/51/52 is a PLL (Phase Locked Loop) based
clock generator that generates output clocks synchronized to one of two selectable input reference clocks.
The de-mapper FEC PLL ratios (in Table 6) enables
the M2052-11-625.0000 to accept “base” input
reference frequencies of:
644.5313MHz (“10GbE LAN”),
690.5692MHz (“10GbE LAN 255/238 FEC”), and
693.4830MHz (“10GbE LAN 255/237 FEC”).
FEC_SEL1:0
Mfec Rfec
1 0
P_SEL2:0
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M2050/51/52
Integrated
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SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
dividers also control the phase detector frequency. The
feedback divider (labeled “Mfin Divider”) provides the
broader division options needed to accomodate various
reference clock frequencies.
For example, the M2051-11-625.0000 (see “Ordering
Information” on pg. 12) has a 625.00MHz VCSO
Configuration of single-ended input has been facilitated
by biasing nDIF_REF0 and nDEF_REF1 to Vcc/2, with 50kΩ
to Vcc and 50kΩ to ground. The input clock structure,
and how it is used with either LVCMOS/LVTTL inputs or
a DC- coupled LVPECL clock, is shown in Figure 4.
frequency:
• The de-mapper FEC PLL ratios (in Tables 5 and 6)
•
enable the M2051-11-625.0000 to accept “base” input
reference frequencies of: 625.00MHz (“10GbE”),
644.5313MHz (“10GbE LAN”), and 669.6429MHz
(“10GbE 255/238 FEC”).
The Mfin feedback divider enables the actual input
reference clock to be the base input frequency
divided by 1, 4, 5, or 25. Therefore, for the base input
frequency of 625.00MHz, the actual input reference
clock frequencies can be: 625.00, 156.25, 125.00, and
25.00MHz. (See Table 3 on pg. 3.)
LVCMOS/
LVTTL
50k Ω
VCC
MUX
50k Ω
0
X
VCC
50kΩ
1
127 Ω
82 Ω
LVPECL
VCC
50k Ω
VCC
127 Ω
50kΩ
82 Ω
50kΩ
REF_SEL
Key to Device Variants and Look-up Table Options
Device
Variant
M2050
M2051
M2052
Look-up Table Option
Mfin Lookup Table is:
Mfec Look-up Table is:
Table 4 (mapper LUT)
Table 3
Table 5 (de-mapper LUT)
Table 6 (de-mapper LUT)
Table 8: Key to Device Variants and Look-up Table Options
The M2050/51/52 includes a Loss of Lock (LOL)
indicator, which provides status information to system
management software. A Narrow Bandwidth (NBW)
control pin is provided as an additional mechanism for
adjusting PLL loop bandwidth without affecting the
phase detector frequency.
Options are available for Hitless Switching (HS) with or
without Phase Build-out (PBO). Performance conforms
with SONET/ SDH MTIE and TDEV during a reference
clock reselection.
Allowance for a single-ended input has been facilitated
by a unique input resistor bias scheme, which is
described next and shown in Figure 4.
Input Reference Clocks
Two clock reference inputs and a selection mux are
provided. Either reference clock input can accept a
differential clock signal (such as LVPECL or LVDS) or
a single-ended clock input (LVCMOS or LVTTL on the
non-inverting input).
A single-ended reference clock on the unselected
reference input can cause an increase in output
clock jitter. For this reason, differential reference
inputs are preferred; interference from a differential
input on the non-selected input is minimal.
M2050/51/52 Datasheet Rev 1.0
Integrated Circuit Systems, Inc.
Figure 4: Input Reference Clocks
Differential Inputs
Differential LVPECL inputs are connected to both
reference input pins in the usual manner. The external
load termination resistors shown in Figure 4 (the 127Ω
and 82Ω resistors) is ideally suited for both AC and DC
coupled LVPECL reference clock lines. These provide
the 50Ω load termination and the VTT bias voltage.
Single-ended Inputs
Single-ended inputs (LVCMOS or LVTTL) are
connected to the non-inverting reference input pin
(DIF_REF0 or DIF_REF1). The inverting reference input pin
(nDIF_REF0 or nDIF_REF1) must be left unconnected.
In single-ended operation, when the unused inverting
input pin (nDIF_REF0 or nDEF_REF1) is left floating (not
connected), the input will self-bias at VCC/2.
PLL Operation
The M2050/51/52 is a complete clock PLL. It uses a
phase detector and configurable dividers to
synchronize the output of the VCSO with the selected
reference clock.
The PLL will work correctly, meaning it will phase-lock
the VCSO output to the input reference clock, when the
internal phase detector inputs are able to run at the
same frequency. This means the PLL dividers must be
set appropriately and a suitable reference frequency
must be chosen for the intended output frequency.
When the PLL is not set up appropriately, the VCSO is
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M2050/51/52
Integrated
Circuit
Systems, Inc.
SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
forced to its upper or lower operating limit which is
typically about 250 ppm above or below the VCSO
center frequency (no more than 500 ppm above or
below).
In normal phase-locked condition, the instantaneous
phase error is measured by the phase detector and is
converted to charge pump current pulses. These
current pulses are then integrated by the external loop
filter to create a VCSO control voltage. The loop filter
acts as a low pass filter to remove unwanted reference
clock jitter above a determined frequency or PLL
bandwidth. For reference phase jitter frequencies within
the loop bandwidth, phase jitter amplitude is passed on
to the output clock according to the PLL loop frequency
response curve.
The relationship between the nominal VCSO center
frequency (Fvcso), the Mfin divider, the Mfec divider,
the Rfec divider, and the input reference frequency (Fin)
is:
Mfec
Fvcso = Fin × Mfin × -------------Rfec
The Mfec, Rfec, and Mfin dividers can be set by pin
configuration using the input pins FEC_SEL1, FEC_SEL0,
FIN_SEL1, and FIN_SEL0.
The M2050/51/52 also features a post-PLL (P) divider.
Through use of the P divider, the device’s output
frequency (Fout) can be that of the VCSO (such as
625.00MHz) or the VCSO frequency divided by 4, 5 or
25.
The P_SEL2:0 pins select the value for the P divider.
(See Table 7 on pg. 4.)
Rfec × P
Due to the narrow tuning range of the VCSO
(+200ppm), appropriate selection of all of the following
are required for the PLL be able to lock: VCSO center
frequency, input frequency, and divider selections.
TriState
The TriState feature puts the LVPECL output driver into
a high impedance state, effectively disconnecting the
driver from the FOUT and nFOUT pins of the device. A
logic 0 is then present on the clock net. The impedance
of the clock net is then set to 50Ω by the external circuit
resistors. (This is in distinction to a CMOS output in
Integrated Circuit Systems, Inc.
Narrow Bandwidth (NBW) Control Pin
A Narrow Loop Bandwidth control pin (NBW pin) is
included to enable adjustment of the PLL loop
bandwidth. In wide bandwidth mode (NBW=0), the
internal resistor Rin is 100kΩ . With the NBW pin
asserted (NBW=1), the internal resistor Rin is changed to
2100kΩ . This lowers the loop bandwidth by a factor of
about 21 (approximately 2100 / 100) and lowers the
damping factor by a factor of about 4.6 (the square root
of 21), assuming the same external loop filter
component values.
Under normal device operation, when the PLL is
locked, the LOL Phase Detector drives LOL to logic 0.
Under circumstances when the VCSO cannot fully
phase lock to the input (as measured by a greater than
4 ns discrepancy between the feedback and reference
clock rising edges at the LOL Phase Detector) the LOL
output goes to logic 1. The LOL pin will return back to
logic 0 when the phase detector error is less than 2 ns.
The loss of lock indicator is a low current LVCMOS
output.
Guidelines for Using LOL
Accounting for the P divider, the complete relationship
between the input clock reference frequency (Fin) and
output clock frequency (Fout) is defined as:
Mfin × Mfec
Fvcso = Fin × -------------------------------Fout = -------------------
M2050/51/52 Datasheet Rev 1.0
Any unused output (single-ended or differential) should
be left unconnected (floating) in system application.
This minimizes output switching current and therefore
minimizes noise modulation of the VCSO.
Loss of Lock Indicator (LOL) Output Pin
Post-PLL Divider
P
TriState, in which case the net goes to a high
impedance and the logic value floats.) The 50Ω
impedance level of the LVPECL TriState allows
manufacturing In-circuit Test to drive the clock net with
an external 50Ω generator to validate the integrity of
clock net and the clock load.
In a given application, the magnitude of peak-to-peak
jitter at the phase detector will usually increase as the
Rfec divider is increased. If the LOL pin will be used to
detect an unusual clock condition, or a clock fault, the
FEC_SEL1:0 pins should be set to provide a phase
detector frequency of 5MHz or greater (the phase
detector frequency is equal to Fin divided by the Rfec
divider). Otherwise, false LOL indications may result. A
phase detector frequency of 10MHz or greater is
desirable when reference jitter is over 500ps, or when
the device is used within a noisy system environment.
LOL should not be used when the device is used in a
loop timing application.
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M2050/51/52
Integrated
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SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
Optional Hitless Switching and Phase Build-out
HS/PBO Operation
The M2050/51/52 is available with a Hitless Switching
feature that is enabled during device manufacturing.
In addition, a Phase Build-out feature is also offered.
These features are offered as device options and are
specified by device order code. Refer to “Ordering
Information” on pg. 12.
Once triggered, the following HS/PBO sequence
occurs:
The Hitless Switching feature (with or without Phase
Build-out) is designed for applications where switching
occurs between two stable system reference clocks. It
should not be used in loop timing applications, or when
reference clock jitter is greater than 1 ns pk-pk. The
Hitless Switching sequence is triggered by the LOL
circuit, which is activated by a 4 ns phase transient.
This magnitude of phase transient can generated by the
CDR (Clock & Data Recovery unit) in loop timing mode,
especially during a system jitter tolerance test. It can
also be generated by some types of Stratum clock
DPLLs (digital PLL), especially those that do not include
a post de-jitter APLL (analog PLL).
When the M2050/51/52 is operating in wide bandwidth
mode (NBW=0), the optional Hitless Switching function
puts the device into narrow bandwidth mode when
activated. This allows the PLL to lock the new input
clock phase gradually. With proper configuration of the
external loop filter, the output clock phase change
complies with MTIE and TDEV specifications for
GR-253 (SONET) and ITU G.813 (SDH) during input
reference clock changes.
1. The HS function disables the PLL Phase Detector
and puts the device into NBW (narrow bandwidth)
mode. The internal resistor Rin is changed to
2100kΩ . See the Narrow Bandwidth (NBW) Control
Pin on pg. 6.
2. If included, the PBO function adds to (builds out) the
phase in the clock feedback path (in VCSO clock
cycle increments) to align the feedback clock with
the (new) reference clock input phase.
3. The PLL Phase Detector is enabled, allowing the
PLL to re-lock.
4. Once the PLL Phase Detector feedback and input
clocks are locked to within 2 nsec for 8 consecutive
cycles, a timer (WBW timer) for resuming wide
bandwidth (in 175 nsec) is started.
5. When the WBW timer times out, the device reverts
to wide loop bandwidth mode (i.e., Rin is returned to
100kΩ) and the HS/PBO function is re-armed.
The LOL pin will indicate lock status on a cycle-to-cycle
basis and may be intermittent until PLL phase lock has
fully stabilized.
The optional proprietary Phase Build-out (PBO)
function enables the PLL to absorb most of the phase
change of the input clock during reference switching.
The PBO function selects a new VCSO clock edge for
the PLL Phase Detector feedback clock, selecting the
edge closest in phase to the new input clock phase.
This reduces re-lock time, the generation of wander,
and extra output clock cycles.
The Hitless Switching and Phase Build-out functions
are triggered by the LOL circuit. For proper operation,
a low phase detector frequency must be avoided. See
“Guidelines for Using LOL” on pg. 6 for information
regarding the phase detector frequency.
HS/PBO Sequence Trigger Mechanism
The HS function (or the combined HS/PBO function)
is armed after the device locks to the input clock
reference. Once armed, HS is triggered by the
occurance of a Loss of Lock condition. This would
typically occur as a consequence of a clock reference
failure, a clock failure upstream to the M2050/51/52, or
a M2050/51/52 clock reference mux reselection.
M2050/51/52 Datasheet Rev 1.0
Integrated Circuit Systems, Inc.
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M2050/51/52
Integrated
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SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
PLL bandwidth is affected by the “Mfec” value and the
“Mfin” value, as well as the VCSO frequency. The
FEC_SEL setting can be used to actively change PLL loop
bandwidth in a given application. See “Mfec and Rfec
Divider Look-Up Tables (LUTs)” on pg. 3.
External Loop Filter
To provide stable PLL operation, the M2050/51/52
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
See Tables 9, 10, and 11, Example External Loop Filter
Component Values, on pg. 8.
PLL Simulator Tool Available
RPOST
A free PC software utility is available on the ICS website
(www.icst.com). The M2000 Timing Modules PLL
Simulator is a downloadable application that simulates
PLL jitter and wander transfer characteristics. This
enables the user to set appropriate external loop
component values in a given application.
CPOST
CPOST
RLOOP
OP_IN
nOP_IN
4
RPOST
CLOOP
OP_OUT
9
nOP_OUT
8
nVC
5
VC
6
Refer to the M2050/51/52 product web page at
www.icst.com/products/summary/m2050-2052.htm
for additional product information.
7
Figure 5: External Loop Filter
Example External Loop Filter Component Values
for M2050-11-644.5313 and M2050-11-669.6429
VCSO Parameters: KVCO = 800kHz/V, RIN = 100kΩ (pin NBW = 0), VCSO Bandwidth = 700kHz.
F Ref
(MHz)
Device Configuration
F VCSO FIN_ FEC_ Mfin M R
... SEL1:0
(MHz)
Phase Det.
Freq. (MHz)
Example Loop Filter Component Values
Nominal Performance With Values
R Loop
C Loop
R Post
C Post PLL Loop Damping Passband Post Filter
Bandwidth Factor Peaking (dB) Bandwidth
125.00
644.5313 0 1 0 0 5
33 32
3.9063
61.9kΩ
1.0µF 59.0kΩ 1000pF
577Hz
6.8
0.043
2.7kHz
125.00
669.6429 0 1 1 0 5
15 14
8.9286
44.2kΩ
1.0µF 38.3kΩ 1000pF
908Hz
7.2
0.039
4.1kHz
Table 9: Example External Loop Filter Component Values for M2050-11-644.5313 and M2050-11-669.6429
Example External Loop Filter Component Values
for M2051-11-625.0000
VCSO Parameters: KVCO = 800kHz/V, RIN = 100kΩ (pin NBW = 0), VCSO Bandwidth = 700kHz.
F Ref
(MHz)
Device Configuration
F VCSO FIN_ FEC_ Mfin M R
...SEL1:0
(MHz)
644.5313 625.0000 1 1 0 0
Phase Det.
Freq. (MHz)
32 33 19.5313
Example Loop Filter Component Values
Nominal Performance With Values
R Loop
C Loop
R Post
C Post PLL Loop Damping Passband Post Filter
Bandwidth Factor Peaking (dB) Bandwidth
28.0kΩ
1.0µF 15.0kΩ 1000pF 1.25kHz
7.0
0.04
10.6kHz
Table 10: Example External Loop Filter Component Values for M2051-11-625.0000
Example External Loop Filter Component Values1
for M2052-11-644.5313
VCSO Parameters: KVCO = 800kHz/V, RIN = 100kΩ (pin NBW = 0), VCSO Bandwidth = 700kHz.
F Ref
(MHz)
Device Configuration
F VCSO FIN_ FEC_ Mfin M R
...SEL1:0
(MHz)
693.4830 644.5313 1 1 0 0 1
Phase Det.
Freq. (MHz)
79 85
8.1586
Example Loop Filter Component Values
Nominal Performance With Values
R Loop
C Loop
R Post
C Post PLL Loop Damping Passband Post Filter
Bandwidth Factor Peaking (dB) Bandwidth
51.0kΩ
1.0µF 33.2kΩ 1000pF
8.1
986Hz
0.031
4.8kHz
Table 11: Example External Loop Filter Component Values for M2052-11-644.5313
Note 1: KVCO , VCSO Bandwidth, Mfin x Mfec Divider Value, and External Loop Filter Component Values determine Loop Bandwidth, Damping
Factor, and Passband Peaking. For PLL Simulator software, go to www.icst.com.
M2050/51/52 Datasheet Rev 1.0
Integrated Circuit Systems, Inc.
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SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
ABSOLUTE MAXIMUM RATINGS1
Symbol Parameter
Rating
Unit
VI
Inputs
-0.5 to VCC +0.5
V
VO
Outputs
-0.5 to VCC +0.5
V
VCC
Power Supply Voltage
TS
4.6
V
o
-45 to +100
Storage Temperature
C
Table 12: 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 13: Recommended Conditions of Operation
M2050/51/52 Datasheet Rev 1.0
Integrated Circuit Systems, Inc.
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Integrated
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SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
ELECTRICAL SPECIFICATIONS
DC Characteristics
Unless stated otherwise, VCC = 3.3V +5%,TA = 0 oC to +70 oC (commercial), TA = -40 oC to +85 oC (industrial), FVCSO = FOUT = 622-675MHz,
LVPECL outputs terminated with 50Ω to VCC - 2V
Symbol Parameter
Power Supply VCC
Positive Supply Voltage
ICC
Power Supply Current
All
Differential
Inputs
VP-P
Peak to Peak Input Voltage
VCMR
Common Mode Input
CIN
Input Capacitance
Differential
Inputs with
Pull-down
IIH
Input High Current (Pull-down)
IIL
Input Low Current (Pull-down)
Differential
Inputs
Biased to
VCC/2 1
All LVCMOS
/ LVTTL
Inputs
IIH
CIN
Input Capacitance
LVCMOS /
LVTTL
Inputs with
Pull-down
LVCMOS /
LVTTL
Inputs with
Pull-UP
Differential
Outputs
IIH
Input High Current (Pull-down)
IIL
Input Low Current (Pull-down)
LVCMOS
Output
DIF_REF0, nDIF_REF0,
DIF_REF1, nDIF_REF1
Min
Typ
Max
Unit Conditions
3.135
3.3
3.465
V
175
225
0.15
V
0.5
Vcc - .85 V
Rbias
Biased to Vcc/2 1
VIH
Input High Voltage
VIL
Input Low Voltage
150
µA
µA
150
1
Rpulldown Internal Pull-down Resistance
IIH
Input High Current (Pull-UP)
IIL
Input Low Current (Pull-UP)
Rpullup
Internal Pull-UP Resistance
VOH
Output High Voltage
VOL
Output Low Voltage
REF_SEL, FIN_SEL1, FIN_SEL0,
FEC_SEL1, FEC_SEL0, P_SEL2,
P_SEL1, P_SEL0
Peak to Peak Output Voltage
VOH
Output High Voltage
VOL
Output Low Voltage
Vcc + 0.3 V
-0.3
0.8
V
4
pF
150
µA
µA
-5
50
NBW
50
LOL
Integrated Circuit Systems, Inc.
Vcc - 1.4
Vcc - 1.0 V
Vcc - 2.0
Vcc - 1.7 V
0.4
0.85
V
2.4
VCC
V
IOH= 1mA
GND
0.4
V
IOL= 1mA
10 of 12
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VCC = 3.456V
VIN = 0 V
kΩ
Note 1: Biased to Vcc/2, with 50kΩ to Vcc and 50kΩ to ground. See Figure 4, Input Reference Clocks, on pg. 5
Note 2: Single-ended measurement. See Figure 6, Output Rise and Fall Time, on pg. 11.
M2050/51/52 Datasheet Rev 1.0
µA
µA
-150
2
VCC = VIN =
3.456V
kΩ
5
FOUT0, nFOUT0,
FOUT1, nFOUT1
VP-P
2
VIN =
0 to 3.456V
kΩ
(Note 1)
REF_SEL, FIN_SEL1, FIN_SEL0,
FEC_SEL1, FEC_SEL0, P_SEL2,
P_SEL1, P_SEL0, NBW
µA
µA
-150
nDIF_REF0, nDIF_REF1
VCC = VIN =
3.456V
kΩ
Input High Current (Biased) 1
Input Low Current (Biased)
pF
50
Rpulldown Internal Pull-down Resistance
IIL
4
-5
DIF_REF0, DIF_REF1
mA
Table 14: DC Characteristics
Revised 23Jun2005
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M2050/51/52
Integrated
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SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
ELECTRICAL SPECIFICATIONS (CONTINUED)
AC Characteristics
Unless stated otherwise, VCC = 3.3V +5%,TA = 0 oC to +70 oC (commercial), TA = -40 oC to +85 oC (industrial), FVCSO = FOUT = 622-675MHz,
LVPECL outputs terminated with 50Ω to VCC - 2V
Symbol Parameter
PLL Loop
Constants 1
Min
Typ
Max
Unit Conditions
FIN
Input Frequency
DIF_REF0, nDIF_REF0,
DIF_REF1, nDIF_REF1
10
700
MHz
FOUT
Output Frequency
FOUT0, nFOUT0, FOUT1, nFOUT1
15
700
MHz
APR
VCSO Absolute
Pull-Range
Commercial
KVCO
VCO Gain
RIN
Internal Loop Resistor
±120
±50
800
100
kΩ
2100
kΩ
700
kHz
1kHz Offset
-72
dBc/Hz
10kHz Offset
-94
dBc/Hz Mfin=25,
100kHz Offset
-123
dBc/Hz
Wide Bandwidth
Narrow Bandwidth
BWVCSO VCSO Bandwidth
Φn
Phase Noise
and Jitter
Single Side Band
Phase Noise
@625.00MHz
0.25
0.5
40
65
ps
ps
%
40
50
60
%
200
450
500
ps
20% to 80%
200
450
500
ps
20% to 80%
12kHz to 20MHz
odc
Output Duty Cycle 2
P = 5 or 25
35
FOUT0, nFOUT0,
FOUT1, nFOUT1
P = 1 or 4
50kHz to 80MHz
Output Rise Time
tF
2
Output Fall Time
FOUT0, nFOUT0, FOUT1, nFOUT1
Mfec=Rfec
0.5
Jitter (rms)
@625.00MHz
2
Fin=25.00 MHz
0.25
J(t)
tR
±200
±150
ppm
ppm
kHz/V
Industrial
Table 15: AC Characteristics
Note 1: Parameters needed for PLL Simulator software; see Tables 9, 10, and 11, Example External Loop Filter Component Values, on pg. 8.
Note 2: See Parameter Measurement Information on pg. 11.
PARAMETER MEASUREMENT INFORMATION
Output Rise and Fall Time
Output Duty Cycle
nFOUT
80%
Clock Output
FOUT
80%
20%
tF
20%
tR
VP-P
tPW
(Output Pulse Width)
odc =
tPERIOD
tPW
tPERIOD
Figure 7: Output Duty Cycle
Figure 6: Output Rise and Fall Time
M2050/51/52 Datasheet Rev 1.0
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M2050/51/52
Preliminary Information
SAW PLL FOR 10GBE 64B/66B FEC
DEVICE PACKAGE - 9 x 9mm CERAMIC LEADLESS CHIP CARRIER
Mechanical Dimensions:
Figure 8: Device Package - 9 x 9mm Ceramic Leadless Chip Carrier
ORDERING INFORMATION
Part Numbering Scheme
Part Number:
Standard VCSO Output Frequencies (MHz)*
M205x- yz - xxx.xxxx
Divider Look-up Table Option
See Table 8, page 5.
Output type
1 = LVPECL
(For CML or LVDS clock output, consult factory)
Hitless Switching / Phase Build-out Options
1 = none
2 = Hitless Switching
3 = Hitless Switching with Phase Build-out
Temperature
“ - ” = 0 to +70 oC (commercial)
I = - 40 to +85 oC (industrial)
PLL Frequency (MHz)
See Table 16, right. Consult ICS for other frequencies.
Figure 9: Part Numbering Scheme
622.0800
669.3120
625.0000
669.3266
627.3296
669.6429
644.5313
670.8386
666.5143
672.1600
669.1281
690.5692
Table 16: Standard VCSO Output Frequencies
Note *: Fout can equal Fvcso divided by: 1, 4, 5, or 25.
Consult ICS for the availability of other PLL frequencies.
Example Part Numbers
VCSO Frequency (MHz) Temperature
625.0000
644.5313
commercial
industrial
commercial
industrial
Order Part Number (Examples)
M2051 - 11 - 625.0000 or M2052- 11 - 625.0000
M2051 - 11I 625.0000 or M2052- 11I 625.0000
M2050 - 11 - 644.5313
M2050 - 11I 644.5313
Table 17: Example Part Numbers
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.
M2050/51/52 Datasheet Rev 1.0
Integrated Circuit Systems, Inc.
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